young children's use of functional information to categorize artifacts: three factors that...

Young children's use of functional information tocategorize artifacts: three factors that matter

Deborah G. Kemler Nelson*, Anne Franken®eld,Catherine Morris, Elizabeth Blair

Swarthmore College, Swarthmore, PA 19081-1390, USA

Received 30 July 1999; received in revised form 26 January 2000; accepted 16 June 2000

Abstract

Three experiments addressed factors that might in¯uence whether or not young children

take into account function, as opposed to overall appearance or shape, when they extend the

names of novel artifacts. Experiment 1 showed that 4-year-olds more often extend a name on

the basis of a demonstrated function when that function provides a plausible causal account of

perceptible object structure. Experiment 2 showed that they more often extend a name by

function when they respond slowly, and hence thoughtfully. Experiment 3 demonstrated that

they are more likely to take function into account when they extend names than when they

judge similarities. Comparisons of lexical and non-lexical conditions in younger children

failed to show any differences. Overall, the ®ndings suggest that by 4 years of age, children

may learn names as labels for novel artifact kinds rather than perceptual classes, and that the

processes by which they categorize may be mindful and re¯ective, as in adults. q 2000

Elsevier Science B.V. All rights reserved.

Keywords: Categorization; Artifact categorization; Conceptual development

1. Introduction

Identifying the nature of adults' artifact concepts and describing their acquisition

by children have both turned out to be surprisingly knotty and interesting problems

(e.g. Bloom, 2000). Accounts of adults' artifact concepts differ about whether func-

D.G. Kemler Nelson et al. / Cognition 77 (2000) 133±168 133

Cognition 77 (2000) 133±168www.elsevier.com/locate/cognit

0010-0277/00/$ - see front matter q 2000 Elsevier Science B.V. All rights reserved.

PII: S0010-0277(00)00097-4

COGN I T I O N

* Corresponding author. Department of Psychology, Swarthmore College, Swarthmore, PA 19081-

1390, USA. Fax: 11-610-328-7814.

E-mail address: [email protected] (D.G. Kemler Nelson).

tional criteria play a de®ning role. Accounts of the acquisition of artifact concepts by

young children differ about whether the kinds of categories children learn are

dramatically different from adults'. The primary purpose of the current paper is to

examine artifact categorization in young children, but we begin by considering

mature artifact concepts.

1.1. Adults' artifact categories

It is commonly assumed that functional criteria play an essential role in adults'

artifact concepts and that function overrides appearance as the basis for how we

categorize artifacts (Keil, 1989; Miller & Johnson-Laird, 1976; Rips, 1989). For

example, despite its unusual physical properties, we categorize as a clock an object

that is pyramid-shaped with stacked sections that rotate independently to display the

time of day in hours, minutes, and seconds. However, it is an oversimpli®cation to

say that functional status constitutes the de®ning criterion for basic-level artifact

categories. After all, a broken time-keeper may be a real clock, and an object

designed to be used as a clock, functioning instead as a paperweight, is also a real

clock. To account for such intuitions, it has been argued that intended function (the

function intended by the object designer), rather than current function, is closer to

the conceptual core of mature artifact categories (Bloom, 1996; Keil, 1989; Rips,

1989).

The insight that intended function is the critical factor also has interesting impli-

cations for the role of appearances. Since a categorizer is rarely privy to direct

information about the function intended by an object's designer (Malt & Johnson,

1998), that intention must be inferred, and a good clue often available for an object's

intended function is its current function. Unsurprisingly, many studies indicate that

when functional information is pitted against appearance as a basis for category

generalization, adults generalize on the basis of function. Still, current function is

not an infallible clue nor is it an exclusive clue to intended function. The appearance

of an object and particularly the relation between the appearance and the current

function of an object can also provide information about what the intended function

was and whether or not the current function is a plausible candidate for the intended

one. In particular, the plausibility that the object was designed for the current func-

tion, and, hence, the weight the current function should be given in categorization,

should be greater if the current function does a good job of explaining the intentional

origins of salient and apparently non-accidental aspects of object structure ± that is,

if the structure/function relation is compelling. Conversely, the relevance of the

current function to categorization may be undermined if the object has a suf®cient

number of salient and apparently non-accidental perceptual properties that cannot be

accounted for by the current function, or if the object shares a suf®cient number of

salient and non-accidental properties with other objects known to function in a

different way. Indeed, when functional information is totally lacking, the only

clue to intended function is provided by the object's structural properties.

On this account, evidence that appearance may sometimes play an important role

in adults' artifact categorization (Gentner, 1978; Landau, Smith, & Jones, 1998;

D.G. Kemler Nelson et al. / Cognition 77 (2000) 133±168134

Malt & Johnson, 1992) can be reconciled with the view that functional considera-

tions are nevertheless privileged and criterial. Appearances may be understood to

matter to adults only in a derivative way ± that is, only to the extent that appearances

point to intended functions and help in evaluating whether current functions were

the intended ones. On this view, intended functions (and only intended functions)

serve as the conceptual cores of adult artifact categories, and the act of categorizing

artifacts involves something akin to problem-solving, inference, and theoretical

work (Keil, 1989; Murphy & Medin, 1985) (see also Bloom, 1996, 2000 for a

related, but somewhat different understanding.

1.2. Children's artifact categories

How dramatically different are the processes of artifact categorization in young

children? Relative to adults, preschool children are more likely to base their artifact

categories on salient aspects of appearance, and less likely to take functional infor-

mation into account (Gentner & Rattermann, 1991; Woodward & Markman, 1998).

In most of the relevant studies, categorization is tested in lexical contexts; that is,

children are asked whether artifact names generalize to new objects. A number of

investigators have reported that when similarities in function and in appearance are

pitted against one another, appearance wins out in preschoolers (e.g. Gathercole,

Cramer, Somerville, & Jansen op de Haar, 1995; Gentner, 1978; Graham, Williams,

& Huber, in press; Keil, 1989; Merriman, Scott, & Marazita, 1993; Tomikawa &

Dodd, 1980). Among these investigators, Landau et al. (1998) and Smith, Landau,

and Jones (1996) recently articulated a strong claim that lexical categorization by

young children is lacking in conceptual underpinnings. They concluded that naming

by children 3 years of age or younger is immune to functional information, and that

even 5-year-olds fail to privilege function in naming artifacts. Smith et al. (1996)

found that name generalization in 3-year-olds was entirely based on whatever

aspects of appearance were made to be perceptually salient, without regard to

whether the properties were functionally relevant. Landau et al. (1998) tested a

larger age range and found that name generalization in 2- and 3-year-olds was

impervious to functional information when it depended on the material of the object;

categorization was guided instead by the functionally irrelevant property of shape.

Even 5-year-olds weighed functional information no more heavily than shape and

sometimes less so. Such ®ndings argue that naming in young children is primarily

under the control of a low-level attentional mechanism that operates largely outside

of conceptual in¯uences.

Such a generalization is controversial, however. Kemler Nelson and her collea-

gues have presented evidence that functional information can sometimes have a

substantial impact on how young children generalize novel artifact names. For

example, in one set of studies (Kemler Nelson & 11 Swarthmore College Students,

1995), 3-, 4-, and 5-year-old children were acquainted with a single object that could

have two different functions, but an individual child experienced only one of them.

Test objects, more or less similar in appearance to the original, were designed to

afford only one function. There were marked differences in how the children gener-


alized the name depending on what function they had experienced. Notably, the

impact of function was more dramatic than the impact of appearance similarity.

Further investigations uncovered evidence for a functional in¯uence on lexical

generalization even in 2-year-olds (Kemler Nelson, 1999; Kemler Nelson, Russell,

Duke, & Jones, in press). Together, these studies have motivated a conclusion very

different from that of Landau et al. (1998) and Smith et al. (1996) ± namely, that the

categories underlying young children's names for artifacts sometimes may be

conceptually saturated. In other words, children may use names to refer to concep-

tual kinds (Gelman & Medin, 1993; Gopnik & Meltzoff, 1997; Mandler, 1993; Soja,

Carey, & Spelke, 1992) rather than perceptual classes.

1.3. The current studies

A vexing, but important issue is how to reconcile these apparently inconsistent

results and conclusions. More generally, it would be useful to have a clearer picture

of the circumstances under which young children do and do not incorporate func-

tional information in their categories of artifacts. Seeking such clarity should help to

illuminate the mechanisms that underlie children's categorization processes. Unfor-

tunately, with very few exceptions, suggestions from the existing literature concern-

ing the factors that promote or undermine functional categorization by young

children are based on post-hoc speculation about the discrepancies between results

obtained in different laboratories with different stimulus materials and somewhat

different procedures. Studies speci®cally designed to systematically manipulate

variables that may affect how young children categorize artifacts are needed.

The present paper reports three such experiments. Experiment 1 tests for an

impact of the artifacts themselves ± speci®cally the plausibility of their structure/

function relations. Experiment 2 involves a manipulation of the tempo with which

children respond. Experiment 3 arranges comparisons of categorization under lexi-

cal and non-lexical conditions.

2. The experimental artifacts

We designed four new sets of experimental artifacts for use in our studies. Each

set contained a standard object, whose function could be demonstrated, and two test

objects, used to evaluate the basis for categorization. Within these test pairs, a

functional object was intended to be only moderately similar-looking in relation

to its standard, but to function like it, and a dysfunctional object was intended to be

more similar-looking to its standard, but not functional in the same way.

Drawings of the four standards are shown in Fig. 1. Each was designed with a

particular function in mind. The becket is for dispensing balls one at a time when

several of them are loaded into its vertical tube. The luzak is for drawing circles and

arcs on paper when the arm of the pen-holder is rotated. The vinsel is for stamping a

picture on paper when its top handle is depressed. The ®lsap is for launching a ping-

pong ball into the air when a suspended weight is set in motion.

With one exceptional condition in Experiment 1, these were the functions with


which participants in all the studies were acquainted. We attempted to design arti-

facts in which the relation between structure and function was reasonably transpar-

ent, easy to understand, and compelling. However, since our present purpose was to

investigate conditions that prompt or discourage function-based responding, we

deliberately tried to create objects with somewhat more complicated structure/func-

tion relations than those typically used in our earlier studies. Kemler Nelson et al. (in

press) demonstrated that when the structure/function relations were made extremely

simple, 2-year-olds categorized novel artifacts on the basis of their function even

when the children had to discover the functions of the standards on their own. With

the more complex structure/function relations of the current materials, we did not

expect that, without tuition, preschoolers could discern the intended functions

simply by interacting with the standard objects.


Fig. 1. Drawings of the standard experimental objects.


Fig. 2. Drawings of the test objects for the experimental sets.

Drawings of the test objects are provided in Fig. 2. The dysfunctional becket

could not be loaded with balls, nor was there a hole in the vertical tube for dispen-

sing them. The pen-holder of the dysfunctional luzak was ®xed in place and the pen-

point was embedded in the wooden base. The dysfunctional vinsel had a short and

unmovable rod, no stamp, and a base sealed in Plexiglass. The weight of the

dysfunctional ®lsap was rigidly suspended so it could not swing. At the same

time, by manipulating perceptual properties of the functional test objects in func-

tionally irrelevant ways, we tried to arrange that the dysfunctional objects were more

similar to their standards than the functional objects in both overall appearance and

shape.

We asked naive adults, all college students, to rate the relations between each of

the test objects and their standards. Individually, eight adults rated each test object

for its `similarity in overall appearance' to its corresponding standard. The raters

were uninformed about any of the artifacts' functions, and were asked to only

inspect the pairs of objects visually. Ratings were obtained on a scale of 1 (`highly

similar to the model in appearance') to 7 (`highly dissimilar from the model in

appearance') as the eight object pairs were presented in random order. Given the

speci®c importance that has been attributed to the perceptual property of shape (e.g.

Landau et al., 1998), an additional group of 12 college students carried out the same

kinds of ratings, but with regard to `similarity in shape' alone.

Adults' ratings are shown in Table 1. First, consider similarities in overall appear-

ance. For all four object sets, there was a substantial tendency to rate the functional

object relative to the dysfunctional object as the less similar to its standard. When

the ratings were submitted to an analysis of variance for a 2 (Functional Type) £ 2


Table 1

Mean adult ratings of the test objects for their similarity to the standards in overall appearance and shapea

Test object Type of similarity

Appearance Shape

Becket

Functional 4.62 6.17

Dysfunctional 2.12 2.00

Luzak



Vinsel



Filsap



a Higher numbers indicate less similarity.

(Object Set) design, the main effect of Functional Type was reliable

(F�1; 7� � 75:07, P , 0:001). There was also a main effect of Object Set

(F�3; 21� � 4:44, P , 0:02), but no interaction with Functional Type. Apparently,

both objects are more similar to their standards in some object sets (the beckets and

vinsels) than in others (the luzaks and ®lsaps).

Second, consider similarities that are speci®c to shape. An analysis of variance for

a 2 (Functional Type) £ 2 (Object Set) design yielded a main effect of Functional

Type (F�1; 11� � 191:21, P , 0:001), a main effect of Object Set (F�3; 33� � 3:25,

P , 0:05), and a reliable interaction between them (F�3; 33� � 4:61, P , 0:01). The

tendency to rate the functional objects, relative to the dysfunctional objects, as less

similar in shape was greater in some object sets than others. However, even in the set

that showed the least shape difference (the luzak set), the functional object was rated

by all 12 judges as less similar to its standard than the dysfunctional object.

In summary, adults evaluated both the relations of overall appearance and shape

in line with our intentions.

3. A preliminary experiment: categorization by adults

A preliminary study was carried out to assess how adults categorize the artifact

materials that we were planning to use with children. Since one of the later issues

will be whether categorization is different under lexical and non-lexical conditions,

we tested adults under both conditions also. If our understanding of adults' artifact

concepts is correct, we would expect that the current materials, designed to have

compelling structure/function relations, should be categorized by adults ± both

lexically and non-lexically ± on the basis of function rather than appearance.

3.1. Method

3.1.1. Participants

The participants were 16 college students, eight men and eight women, attending

a private, liberal arts college.

3.1.2. Stimulus materials

The materials included the four experimental object sets and also the props that

were necessary to carry out their functions.

3.1.3. Design

The students were assigned in equal numbers at random to a name and a no-name

condition.

3.1.4. Procedure

The procedure was similar in all essential respects to that later used with children.

On each trial, the function of a standard object was demonstrated, after which the

participant was asked to carry that function out. Then, the ®rst test object (either

functional or dysfunctional, as randomly determined on each trial) was brought out


for inspection, with the participant allowed to try out the function. It was removed

from view and the second test object was brought out for examination. During this

phase, the props necessary to carry out the functions of the objects remained avail-

able to the participant. Finally, the experimenter put the two test objects immedi-

ately in front of the participant, one to the left and one to the right (randomly

determined), and the participant was asked to categorize one of them with the

standard. The order of the stimulus sets was determined at random for each parti-

cipant. No feedback was provided for responses.

The commentary that accompanied the presentation of the standard and the phras-

ing of the subsequent request to choose one of the test objects to categorize with it

depended on the experimental condition. In the name condition, the standard was

labeled when it was ®rst brought out and its name was used several times in a semi-

natural linguistic context as its function was carried out ± for example, `Let me show

you how this ®lsap works.' To elicit categorization, the standard was named again

and the participant was asked to choose another object with the same name. For

example, the experimenter said, `See this ®lsap. Can you show me another ®lsap?' In

the no-name condition, attention was drawn to the standard both at initial presenta-

tion and at the beginning of the test, but without naming it ± for example, `Let me

show you how this works.' At the test, the participant was asked, `See this. Can you

show me another one of these?'.

3.2. Results and discussion

Without exception, adults classi®ed the artifacts on the basis of function. Choices

of the functional object over the more similar-looking, but dysfunctional object

occurred 100% of the time in both conditions. Thus, the tendency of adults to

name and otherwise categorize artifacts on the basis of their (intended) function is

captured well by the stimulus materials that we have constructed and the procedural

context that we have designed.

4. Experiment 1: effects of the plausibility of functions in relation to structures

The relationship between the structural design and the demonstrated function of

artifacts may have a major impact on whether or not young children take the current

function into account when they name. We have argued that when children can

`make sense' of the relation, they are more likely to be in¯uenced by the functional

information (Kemler Nelson, 1999; Kemler Nelson et al., 1995, in press). The

artifacts used in previous studies reporting function-based naming in young chil-

dren, as well as those used in the preliminary study just reported, were designed with

this idea in mind. The functions attributed to the objects were based on aspects of

structure that were easily perceptible, the physical principles relevant to enabling (or

disabling) the function were fairly elementary and relatively easy for the children to

understand, and the functions provided a reasonably compelling explanation of why

the similar-functioning objects had the structures they did.

The failure to meet one or more of these conditions may have sometimes under-


mined the appearance of function-based naming in young children. For example, in

the classic study by Gentner (1978), a hybrid test object that looked exactly like a

jiggy (an opaque box with a cartoon face painted on it), but that functioned like a

zimbo (dispensing gumballs when a lever was moved) was identi®ed as a jiggy by 2±

5-year-old children. Note that the function of the object was based on structural

features entirely hidden from view, enabled by a physical mechanism that young

children were unlikely to understand, and served as an unconvincing explanation for

the appearance of the similar-functioning test object (which was also identical to that

of an object previously demonstrated to have a different function).

The proposal we advocate relates back to our discussion of artifact categorization

in adults. Young children understand artifacts to be intentionally designed for some

functional purpose (Kelemen, 1999), and that this may afford them some precursors

of the adult conception that artifact categories are grounded speci®cally in their

intended function. Children may also share the adult intuition that a current use of

an object is likely to be its originally intended function ± and thus a valid basis for

categorizing the object ± to the extent that the current function underwrites a

compelling account of the causal origin of the object's structural properties.

Until now, this proposal has been largely speculative and has relied on post-hoc

comparisons of results from different laboratories using different stimulus materials.

Experiment 1 is designed to put it to a direct empirical test.

The manipulation of plausibility was accomplished by varying the functions

assigned to the standard objects. In a plausible-function condition, the standards

were demonstrated with the functions for which we had intentionally designed the

artifacts ± that is, the functions described previously. The new condition was an

implausible-function condition, for which we created new functions for the same

objects. These new functions were designed to be less plausible than the original

ones in the sense that they provided less compelling causal accounts of some salient

and apparently non-accidental aspects of the objects' structures. We ask whether

young children shown plausible functions, relative to those shown implausible

ones, would be more likely to use the demonstrated functions as a basis for name

generalization.

4.1. Method

4.1.1. Participants

The participants were 32 preschool children, 18 boys and 14 girls, attending

preschools in upper-middle-class suburbs of Philadelphia, PA. Their mean age

was 4 years 4 months, with a range of 4 years 0 months to 4 years 11 months.


The experimental object sets were used, as well as two warm-up sets designed to

acquaint the children with the procedure. The ®rst warm-up set consisted of two

different toy trucks and a toy boat, and the second consisted of two novel, plastic

percussion toys, different only in size and color, and a pair of kitchen tongs. It was


expected that the children would know the name for the trucks, but not for the

percussion toys, which the experimenter referred to as dumples.

Props used in the plausible-function condition consisted of balls for the beckets

and the ®lsaps, pens and paper for the luzaks, and an ink pad and paper for the

vinsels. Props in the implausible-function condition consisted of a plastic snake for

the beckets, a snail shell stuffed with adhesive for the luzaks, aluminum foil for the

vinsels, and a free-standing lead-eraser for the ®lsaps.

Table 2 provides information about how the plausible and implausible functions

were described and demonstrated to the children. In creating the implausible func-

tions, we ensured that the test objects that were functional and dysfunctional with

respect to the plausible functions would have the same affordances with respect to

the implausible functions. For example, the functional luzak could both draw circles

and spin snails, and the dysfunctional (but more similar-looking) luzak could do

neither.

To check that the functions designated plausible were more compelling as expla-

nations of the designer's intentions than those designated implausible, we obtained

additional ratings of our stimulus materials from adults. Each of 12 college students,


Table 2

Descriptions of the functions of the standard objects in the plausible- and implausible-function conditions

of Experiment 1

Object Verbal description Further information

Plausible

Becket `When you put balls in here, it

drops them one at a time.'

Three golf balls were

inserted in the vertical tube.

Luzak Ìt draws circles and curves.' The pen was in place and

paper was supplied.

Vinsel Ìt stamps.' The stamp was inked and

paper was supplied.

Filsap `When you put a ball here, it hits

it into the air.'

A ping-pong ball was placed

on the tee and the pendulum

was set in motion by being

pulled away from it.

Implausible

Becket À toy snake can wriggle in it.' A toy snake was inserted in

the vertical tube.

Luzak À snail can spin on it.' The shell of a snail was

attached to the underside of

the base.

Vinsel Ìt crinkles the foil.' Aluminum foil was wrapped

around the spring.

Filsap Ìt knocks over the eraser.' A lead eraser was put on end

directly on the base and was

upset by pulling the

pendulum toward it.

none of whom had encountered the objects before, completed a series of eight trials.

On each trial, one function of a standard object was demonstrated by the experi-

menter, after which the judge rated on a scale of 1 (`very unlikely') to 5 (`very

likely') `the probability that this object was originally designed for carrying out the

function that I just demonstrated'.

The mean ratings that the functions were the intended functions are shown in

Table 3, separately for the plausible and implausible functions. These ratings were

submitted to an analysis of variance for a 2 (Plausibility) £ 4 (Object Set) within-

subjects design. The main effect of Plausibility was reliable (F�1; 11� � 323:24,

P , 0:001), as was the interaction (F�3; 33� � 6:78, P , 0:005). There was an

overwhelming tendency to rate the plausible function as originally intended

(modal rating of 5 for every standard) and the implausible function as unintended

(modal rating of 1 for every standard). The interaction involving Object Set is due to

the fact that the difference between plausible and implausible functions was least

compelling for the ®lsaps, but even in this case, 11 of 12 raters rated the plausible

function as the more likely to be the intended one.

4.1.3. Design

The children were randomly assigned in equal numbers to the plausible-function

condition and the implausible-function condition.

4.1.4. Procedure

Children were tested individually in a session of about 10 min. It began with a

two-trial, warm-up phase (trucks followed by dumples) prior to the four experimen-

tal trials. The function of the truck was described as `It goes zoom, zoom', while the

object was moved back and forth. The function of the dumpel was that `it spins and

clicks', described while the object was put in motion. The order of object sets on the

experimental trials was determined at random for each participant.

At the beginning of the session, a hand puppet was introduced as `Mr. Rabbit',

and the child was told that the experimenter's friend had sent along some things to

show to the child and Mr. Rabbit. Six trials followed, the ®rst two of which were

warm-up and did not differ between conditions. At the beginning of each trial, a

standard object was brought out and labeled (e.g. `This is a ®lsap.'), and its function

(appropriate to the child's condition) was demonstrated and described (e.g. `When


Table 3

Mean adult ratings of the likelihood that the plausible and implausible functions were the functions

intended by the object designer

Test object Type of function

Plausible Implausible

Becket 4.58 1.08

Luzak 4.75 1.33

Vinsel 4.83 1.00

Filsap 4.50 1.92

you put a ball here, it hits it into the air.'). Then, the child was encouraged to try out

the function, and the object's name was used several times in a semi-natural linguis-

tic context. For example, the experimenter said, `Look at this ®lsap. Do you have a

®lsap at home? Have you seen a ®lsap before? This ®lsap is really neat, don't you

think?' After the standard was used, it was removed to a central location in front of

the child, but out of reach. The test objects were then presented one at a time (with

the order randomly determined on each trial), and with the props still available the

child was given the chance to try each of them out. To elicit the child's test response,

the experimenter placed the two test objects in front of the child (position randomly

determined) and said, `One of these is a ®lsap and the other is not. Can you tell me

which one of these is a ®lsap?'. Previously, the test objects had not been named, but

just referred to as `things'. No differential feedback was provided for the child's

choices.


A preliminary check indicated that there was no difference between the plausible-

and implausible-function conditions in children's tendency to manipulate the test

objects in a functionally relevant way. Such exploration occurred for 95% of the test

objects in the plausible-function condition, and for 97% of the test objects in the

implausible-function condition. Thus, on the vast majority of trials in both condi-

tions, children's actions on the test objects were suf®cient to reveal the objects'

functional affordances.

Table 4 shows the percentage of trials on which children in the plausible- and

implausible-function conditions generalized the name of each standard to a func-

tional test object over a dysfunctional test object. An analysis showed that there was

a reliable difference between the conditions in the total number of functional choices

(t�30� � 4:30, P , 0:001). The tendency to make more functional choices in the

plausible-function condition was consistent across the four stimulus sets, and statis-

tically reliable in the cases of the luzaks and the vinsels considered singly

(x2�1� � 11:22, P , 0:001 and x2�1� � 14:54, P , 0:001, respectively). Only in

the plausible-function condition did functional choices predominate

(t�15� � 18:90, P , 0:001). Of 16 participants in the implausible-function condi-


Table 4

Percentages of choices of the functional over the dysfunctional object in the two conditions of Experiment

1

Object set Condition

Plausible function Implausible function

Becket 75 50

Luzak 94 38

Vinsel 100 38

Filsap 75 62

Overall 86 47

tion, ®ve produced more functional than dysfunctional choices, four produced equal

numbers, and seven produced more dysfunctional choices. Thus, participants for

whom the implausible function was demonstrated were about equally likely to make

functional and dysfunctional choices. By contrast, in the plausible-function condi-

tion, 14 of 16 participants produced more functional than dysfunctional choices, two

produced equal numbers, and none produced more dysfunctional choices.

These results clearly show that children were more likely to use current functional

information as a basis for generalizing the names of novel artifacts when the demon-

strated functions were more plausibly related to the objects' structures, and, accord-

ingly, more plausibly the functions intended by the objects' designers. By

themselves, the ®ndings from the plausible-function condition are important as

another demonstration that preschool children categorize on the basis of function

over overall appearance or shape under appropriately enabling conditions. As the

number of different artifact sets showing this pattern continues to accrue in the

literature, the common generalization that preschoolers are predominantly appear-

ance-based categorizers or shape-based categorizers seems more and more suspect.

Still, the most important outcome of the present study involves the comparison

between the plausible- and implausible-function conditions for it offers systematic

empirical support for a factor that distinguishes contexts in which young children

will and will not privilege function over appearance.

The present ®ndings draw most singular attention to the role of the compelling-

ness of the structure/function relation as being critical, as opposed to structure/

function transparency or comprehensibility. On the face of it, in the implausible-

function condition, no less than in the plausible-function condition, the object prop-

erties that enabled or disabled function were easily perceptible and how they did so

was easily understandable. Hence, it would seem that transparency and comprehen-

sibility are not suf®cient to produce a predominance of function-based responding,

although they may still be necessary. Indeed, for a child to evaluate compellingness

± that is, whether a candidate function provides a plausible account of the origins of

structural properties ± the child will need to have information about the functionally

relevant structure (making transparency relevant) and will have to be in command of

the physical principles that mediate between that structure and that function (making

comprehensibility relevant).

Still, highlighting the role of compellingness may help to explain an otherwise

puzzling failure of the Smith et al. (1996) children to show any trace of function-

based categorization in a lexical condition. These investigators presented direct

evidence that their 3-year-olds could evaluate correctly whether or not the test

objects could function like their standards. Indeed, the children used such knowl-

edge in a non-lexical task. An informal assessment of the compellingness of the

structure/function relations embodied in their artifacts suggests that a sometimes

missing factor may have been compellingness. For example, one of their objects was

an amlas, the demonstrated function of which was that `a toy dog sits in it'. Such an

imputed function does not do a convincing job of explaining the presence of gears on

this object, parts which were demonstrably salient to the children. Hence, we

suggest, their children may have found it implausible that the standard amlas was


actually designed for the function that the experimenter identi®ed, with the result

that that information was discounted as a basis for lexical generalization.

The results of the present study are not unique in suggesting that young children

are sensitive to designers' intentions when they name and categorize artifacts.

Bloom (2000), in a line of argument related to the current one, has suggested that

function-based categorization will occur in young children when the functions that

are demonstrated are suf®ciently re¯ective of intentional design ± that is, not some-

thing an object could do by accident. He hypothesized that the strong shape bias

observed by Landau, Smith, and Jones (1988) could be attributable to the fact that

the functions that were demonstrated (for example, being able to soak up liquid)

were simple and dependent only on the material used to construct the objects.

Perhaps, then, children used object shape to categorize because the current function

was not regarded as a good cue to the intended function, whereas the property of

shape often is. If so, children should discount shape similarity if they have reason to

understand it as uninformative about functional similarity. Such reasoning moti-

vated an ingenious study by Bloom, Markson, and Diesendruck (1998) (cited in

Bloom, 2000), in which they showed that the shape bias in 4-year-olds could be

undermined by providing a hint that two objects having the same shape were

designed with different functions in mind. They did this by showing the shape

alternative as a tight-®tting container for the standard object prior to the test for

name generalization. Without such a demonstration, children categorized by shape

over material; with it, they did not. So, when sameness of shape is not a credible

basis for inferring intended similarity in function, young children tend to abandon

shape as a preferred basis for categorization.

Diesendruck and Markson (1999) investigated when 3-year-old children will

privilege functional information over shape in categorizing an artifact. They

found that children divided their responses about equally often between function

and shape when they were told what an object `can' do, but that the children favored

functional similarity when directly instructed about what functions the test objects

were and were not `made for'. These results, like ours, suggest that children are

swayed more toward functional information when it is clearly intentional. The

present results are perhaps more dramatic in that we show an apparent in¯uence

of intentional considerations even without directly mentioning them to the children.

Indeed, it seems unlikely that children are often explicitly informed about designers'

intentions when they encounter artifacts outside the laboratory.

Recently, other indications have appeared that young children are sensitive to

information about the intentional origins of artifacts. Kelemen (1999) demonstrated

that 4- and 5-year-olds understand artifacts as designed for a purpose, and, further-

more, that they believe the function intended by the object designer takes prece-

dence over some current use in deciding what the object is `for'. (See Matan (1985),

however, for some apparently contrary results.) Two relevant studies also focussed

on young children's intentional understanding of pictorial representations ± an

especially interesting class of artifacts. Bloom and Markson (1998) showed that

3- and 4-year-olds named their own drawings in accord with their prior representa-

tional intent, despite the fact that the properties of the drawings they named (their


shapes) were often uninformative about what referent was intended. In addition,

Gelman and Ebeling (1998) found that 3-year-olds were more inclined to name

drawings that resembled objects by the names of those objects if they were told a

story that implied that an artist intended a representation of the object rather than

that the very same drawing had been created by accident. Indeed, Bloom and

Gelman (in press) showed that information about the intentional versus accidental

origins of common artifacts, such as knives, can have an analogous effect on young

children's naming. Taken together, these various strands of evidence converge with

the present study in suggesting that, at an early age, reasoning about designers'

intentions may play a powerful role in children's concepts of artifacts.

Many of the earliest studies of the role of functional information in children's

categorization were an outgrowth of the proposal by Nelson (1973, 1974) that the

concepts of the young child should have a functional rather than a perceptual

core because they are the products of sensori-motor activities. Such a view of

how functional information might impact young children's categorization ±

namely, as the consequence of an infantile cognitive orientation ± contrasts

with the current understanding of children's attention to function as cognitively

motivated, and akin to adults'. In line with the latter view, evidence from the

present study suggests that young children's reliance on functional information to

categorize artifacts is not simply the consequence of some low-level, sensori-

motor process. In the implausible-function condition, no less than the plausible-

function condition, children could carry out the same action on the functional test

alternative (but not on the dysfunctional alternative) that they had practiced on

the standard. Thus, if the generalizability of actions were the source of function-

based categorization, there would be no reason to expect the differential tendency

that we observed to favor functional choices in the plausible-function over the

implausible-function condition.

5. Experiment 2: effects of response tempo

The results of Experiment 1 suggest that the impact of function is mediated by

deliberative and re¯ective conceptual processes. That 4-year-old children seem to

privilege object function only when it supports a plausible causal account of object

structure seems to imply that young children may engage in the kind of mindful

concept learning that has been attributed previously to adults (e.g. Murphy & Medin,

1985). One purpose of Experiment 2 is to seek converging evidence for this propo-

sal. On the view that young children are conceptually engaged when they categorize

artifacts by their functions, their tendency toward function-based categorization

could be undermined by forcing them to respond under time pressure. To evaluate

this hypothesis, children in Experiment 2 are tested on the plausible artifact cate-

gories used in the ®rst experiment, as we attempt to systematically manipulate the

tempo with which they make their category decisions.

Experiment 2 also provides a potentially informative way to distinguish the present

account of how function-based categorization occurs in young children from an


alternative offered by Landau et al. (1998) and Smith et al. (1996). These investigators

argued that the kind of slow, deliberative process that allows conceptual information

about function to guide artifact categorization in adults is wholly or largely absent in

young children. To deal with the sometime ®nding that young children do name by

function, they argued that the kinds offunctions (e.g. painting) used by Kemler Nelson

et al. (1995) were already familiar to young children, and had been experienced

repeatedly in the context of speci®c object parts (e.g. brushes). Accordingly, the

children already had well-learned associations between the function, the functional

parts, and the context of naming. On this view, when young children take function into

account when they name, it is not through the same kind of thoughtful, analytic

process postulated for older children and adults; instead, it is by way of an automatic

and unre¯ective associative mechanism that comes into play as non-deliberatively as

perceptual salience effects and overlearned attentional biases.

Previously (Kemler Nelson, 1999; Kemler Nelson et al., in press), we have ques-

tioned whether this kind of automatic associative-learning mechanism is suf®cient to

account for observations of function-based categorization when the artifacts' func-

tions were unquestionably unfamiliar (e.g. the color-changers of Kemler Nelson et

al., 1995). The results of Experiment 1 also seem to be problematic for the associa-

tive account. It is dif®cult to sustain an argument that, overall, the kinds of functions

demonstrated in the plausible-function condition (for example, rotating the arm of

the luzak to draw circles) were more frequently experienced pre-experimentally in

the presence of the functional parts of the objects than the kinds demonstrated in the

implausible-function condition (for example, twirling the base of the luzak in order

to spin a snail).

The tempo manipulation of Experiment 2 should also be relevant. If, in naming

the plausible-function artifacts, young children take function into account in a

re¯ective, conceptual way, then they should produce function-based categorizations

in an unspeeded condition, but fewer of them in a speeded condition. On the other

hand, if children's function-based naming of these artifacts is mediated by automatic

and well-learned associations, there is little reason to expect that the response tempo

manipulation will have any effect.

5.1. Method

5.1.1. Participants

The participants were 19 boys and 13 girls, whose mean age was 4 years 4

months, with a range of 4 years 0 months to 4 years 8 months. They attended

preschools in middle-class and upper-middle-class suburbs of Philadelphia, PA.

None had participated previously. One additional child was eliminated from the

sample due to a consistent response bias.


The four experimental sets were the ones used in the earlier studies. In addition,

four warm-up object sets were employed. Two of them, (a) trucks plus a boat and (b)

percussion toys plus tongs, had been used before. The new warm-up sets consisted of


(c) two Slinkys, one plastic and one metal, plus tongs, and (d) two different instru-

ments for punching holes in paper plus a plastic can opener. The function of the

Slinky was that ìt moves from side to side', as its two ends are placed in the palms of

the hands. The hole-puncher was called a seekip, and its function described as ìt

makes holes in paper', while that use was demonstrated.

5.1.3. Design

Sixteen children were assigned at random to each of the two experimental condi-

tions, speeded and unspeeded.

5.1.4. Procedure

Each child participated individually in a single session, less than 15 min in length.

Each session consisted of four warm-up trials, followed by four experimental trials.

The order of stimulus sets for the warm-up trials was the same for all children: truck,

Slinky, dumpel, and seekip, arranged from more to less familiar. The order of

stimulus sets for the experimental trials was determined randomly for each partici-

pant, as was the order of the functional and dysfunctional objects within each trial.

As on each trial in Experiment 1, the experimenter ®rst brought out the standard

object, named it, described and demonstrated its (plausible) function, and used its

name repeatedly while the child was encouraged to try out the function several

times. Then, the standard was removed to a central location on the table out of

the child's reach.

The manipulation of speed occurred during the presentation and questioning of

the test objects, and occurred during both the warm-up phase and the presentation of

the experimental sets. The warm-up phase was more extended in this study in order

to establish a tempo prior to the presentation of the experimental sets. Prior to

bringing out the ®rst test object, the experimenter gestured toward the standard

and reminded the child of its name (`Remember, this is a ®lsap.'), and then contin-

ued, `Now look at this', placing the test object in front of the child. In the speeded

condition (for both warm-up and experimental sets), the question about the name of

the test object followed immediately (Ìs this a ®lsap?'). In the unspeeded condition

(for both warm-up and experimental sets), the question occurred 10 s after the object

was set before the child. In both conditions, the props remained accessible to the

child during this time, and the child was free to try out the function of the test object.

After obtaining the ®rst test response, the experimenter removed the test object, and,

reminding the child again of the name and function of the standard, brought out the

second test object, questioning its name either immediately (speeded condition) or

after 10 s (unspeeded condition). Note that in the current study, unlike the previous

one, the child was asked to classify each of the test objects individually, instead of

making a forced choice between them. We found that this modi®cation allowed us to

more effectively manipulate the tempo with which the child responded.


In order to evaluate the effect of the speed manipulation, we computed the number


of acceptances of the functional and the dysfunctional object in the two experimental

conditions. To have a measure that would be most sensitive to the tempo manipula-

tion, we inspected the children's ®rst responses following the experimenter's ques-

tion. So, for participants in the speeded condition, this was not always the child's

®nal response on the trial, and for participants in the unspeeded condition, it was not

always the child's ®rst response. The relevant means, recalculated as the percentage

of times the name was generalized, are shown in the top of Table 5. When the scores

were submitted to an analysis of variance for a 2 (Condition: Speeded or

Unspeeded) £ 2 (Object Type: Functional or Dysfunctional) mixed design, there

was a signi®cant main effect of Object Type (F�1; 30� � 10:73, P , 0:01), and a

marginally signi®cant interaction between Condition and Object Type

(F�1; 30� � 3:22, 0:05 , P , 0:10). Tukey's test, adjusted according to Cicchetti

(1972), was used to further investigate the interaction, and it revealed that only

within the unspeeded condition was there a reliably greater tendency (P , 0:05)

to generalize the name to the functional object than the dysfunctional object. (The

least signi®cant difference between the raw score means was 1.03.) Of the 16

children in the unspeeded condition, 13 made quantitatively more functional than

dysfunctional generalizations, two made an equivalent number, and only one gener-

alized to the dysfunctional object more often. Comparable ®gures for the speeded

condition were four, ®ve, and seven, respectively.

A potentially more sensitive way to examine the relationship between response

tempo and function-based naming is to classify each response according to the

speed with which it was actually generated (as opposed to the experimental

condition in which it was elicited). This is because the experimental manipula-


Table 5

Percentages of names generalized to functional and dysfunctional objects, partitioned in three different

ways

Response type and partition Test object

Functional Dysfunctional

First responses after question, partitioned by

experimental condition

Speeded 69 58

Unspeeded 72 34

First responses, partitioned by time to ®rst

response (collapsed across conditions)

, 3 s 68 81

3±12 s 73 39

. 12 s 70 23

First responses, partitioned by active exploration

time (collapsed across conditions)

, 2 s 58 77

2±11 s 76 27

. 11 s 83 24

tion of speed, through the timing of the test question, was only moderately

successful. For example, children in the speeded condition sometimes delayed

their ®rst response for more than 10 s following the presentation of the test object

despite the fact that the experimenter asked for a categorization immediately

upon bringing it out. Conversely, children in the unspeeded condition sometimes

offered their ®rst response well before the question was asked.

Accordingly, the entire data set was reclassi®ed on the basis of the time the child

actually took to make a ®rst response following the presentation of a test object. To

evaluate the reliability of the measures of response times, an independent judge

calculated them from videotapes of 14 children, seven in each condition. The agree-

ment between this judge and the original experimenter was high (r�111� � 0:96).

Using the measures of the experimenter, trials were partitioned into three categories

according to whether the child took fewer than 3 s (very short), 3±12 s (intermedi-

ate), or greater than 12 s (long). The cut-off between the ®rst and second categories

was decided a priori as the time to make a virtually immediate response, and that

between the second and third as a way to partition the remaining trials into samples

of approximately equal size.

The middle panel in Table 5 shows the percentage of name generalizations to the

functional and dysfunctional test objects for these three different kinds of trials.1

With increasing time to respond, the decrease in generalizations to the dysfunctional

(but more similar-appearing) object is particularly dramatic: with very short

response times, 44 of 54 dysfunctional objects were named as the standard, but

with long response times, only ten of 43 were so named. A x 2-test established

that the overall tendency to accept the dysfunctional object was reliably different

across response times (x2�2� � 35:19, P , 0:001). Furthermore, this relation held

reliably in three of the four object sets considered individually: for beckets

(x2�2� � 10:15, P , 0:01) (82% of the dysfunctional objects were accepted at

very short times compared to 20% at long times); for vinsels (x2�2� � 18:21,

P , 0:001) (100% of the dysfunctional objects were accepted at very short times

compared to 10% at long times); and for ®lsaps (x2�2� � 7:68, P , 0:05) (75% of

the dysfunctional objects were accepted at very short times compared to 27% at long

times). The association between naming practices and response times was not reli-

able for the dysfunctional luzak, but it was in the same direction (69% at very short

times and 31% at long times). An overall x 2-test, as well as tests on individual object

sets, failed to detect any reliable association between response times and how the

functional object was named.

Finally, the data were partitioned on the basis of the actual time children spent in

active exploration of the test object prior to making their ®rst response. Active

exploration time was calculated as the amount of time the child spent handling

and exploring the object in a functionally relevant way. Visual exploration without

any touching or manipulation of the object was not counted. A reliability check


1 Experimental condition and actual ®rst response time were related, albeit imperfectly. In the speeded

condition, 57% of ®rst responses fell into the fastest category and only 14% in the slowest; in the

unspeeded condition, the respective ®gures were 17 and 56%.

between an independent judge and the original experimenter, based on seven chil-

dren from each experimental condition, showed a high degree of agreement between

them (r�111� � 0:936).

The results of a partition based on the experimenter's measures of active explora-

tion time are shown in the lower panel of Table 5, according to whether children

explored fewer than 2 s (hardly at all), 2±11 s (an intermediate amount of time), or

more than 11 s (extensively). The association between naming and exploration times

was reliable overall (x2�2� � 34:18, P , 0:001), and independently for all stimulus

sets but the luzaks (x2�2� $ 8:48, P , 0:01, for the beckets, vinsels, and ®lsaps,

individually). With increasing time there was a decreasing tendency to generalize

the name to the dysfunctional objects. In addition, there was some indication that

longer exploration times were associated with differential naming of the functional

object (x2�2� � 6:59, P , 0:05 for the overall results). For the functional objects, in

contrast to the dysfunctional objects, longer exploration times led to an increasing

tendency to generalize the name. Quantitatively, the same relation obtained in all

four stimulus sets was considered independently, but it was only reliable for the

beckets (x2�2� � 6:41, P , 0:05).

Thus, three different ways of inspecting the data converge on the conclusion that

function-based naming in young children is associated with a slower and more

deliberative process. Such a result is highly compatible with our suggestion that

the process by which children take account of function when they categorize arti-

facts is akin to the mindful, conceptual process by which adults also do. Moreover,

the ®nding is unexpected under the hypothesis that function-based naming occurs in

young children only through the mechanism of automatic associations. Smith et al.

(1996) speculated that adults are able to inhibit rapid, involuntary pulls on attention,

in order to allow knowledge of function to come into play. They denied such a

possibility in young children. Yet, the current data provide compelling evidence

that exactly this kind of process is occurring in 4-year-olds. It appears that the

children's initial (that is, rapid) response to the dysfunctional, but similar-looking

test object is to name it as the standard ± presumably based on shape or other salient

features of its appearance. Their more considered (that is, slower) response to the

same object is to deny that it belongs to the same lexical category as the standard ±

presumably because of its (dys)functional character. To some extent, but less

dramatically, the converse process may be operating with the functional, but less

similar-looking test object. The more the functional affordance of that object is

explored, the more likely the children are to name it as the standard.

The results of Experiment 1 identi®ed one factor that may distinguish cases in

which young children do and do not categorize artifacts in accord with their function

± namely, the compellingness of the structure/function relations embodied in the

objects. The results of Experiment 2 suggest an additional candidate ± namely, the

tempo with which the children make their category decisions. It is possible that this

factor also may play a role in reconciling previously con¯icting ®ndings in the

literature. Under experimental procedures in different laboratories, there may be

more or less time pressure on young children to make their naming responses

(Kemler Nelson, 1999).


6. Experiment 3: lexical effects

In our previous studies, we have obtained evidence that 4-year-old children some-

times categorize artifacts on the basis of function over appearance. It is notable that

these observations have occurred in the context of lexical categorization in parti-

cular. Smith et al. (1996) presented some intriguing evidence that when 3-year-olds'

categorizations are compared across lexical and non-lexical conditions, functional

information may sometimes in¯uence the latter, but not the former. When the

children in their studies were asked to generalize the names of novel artifacts to

test objects (as here), they appeared to be immune to functional information. Yet,

when children in a no-name condition were simply required to compare each test

object to its original, unnamed standard, and asked, `Is this one like that?', functional

information had an effect. This led Smith et al. (1996) to the provocative conclusion

that young children's immunity to conceptual information in categorization is speci-

®c to lexical contexts. The `dumb attentional mechanism' that they posited was said

to be selectively elicited when objects are given names, as in `This is a ___',

focusing young children on salient perceptual properties and blocking the in¯uence

of conceptual knowledge that the children might otherwise use to categorize.

Concerning the functional categorization of artifacts, the comparison by Smith et

al. (1996) of lexical and non-lexical conditions is unique, but it resonates with a

larger set of investigations in which researchers have systematically studied the

effects of naming on how infants and young children categorize and reason about

objects. A number of these studies report that naming tends to increase, rather than

decrease, children's categorization of objects into conceptual kinds (e.g. Markman

& Hutchinson, 1984; Waxman & Hall, 1993). Providing names seems to direct

infants' and young children's attention to taxonomic relations (as opposed to

thematic relations, for example). However, since taxonomic relations tend to be

confounded with relations of perceptual similarity in a number of these cases,

many of the results may still be compatible with the overall conclusion by Smith

et al. (1996) that names are particularly powerful in focussing children on appear-

ances.

Indeed, when investigators have tried to untangle true taxonomic categorization

from responses based on appearance, the message has been decidedly mixed. In

comparing name and no-name conditions, Baldwin (1992) showed that categoriza-

tion at the superordinate level (as opposed to thematic responding) was enhanced by

names even when perceptual similarity did not favor it. Still, in another study, she

reported that names weakly increased the likelihood that preschoolers grouped

together taxonomically unrelated items that were similar in shape, as opposed to

different-shape items from the same superordinate category. Imai, Gentner, and

Uchida (1994) found that names increased categorization based merely on similar

shape in 3- and 5-year-olds. However, whereas names also depressed true taxonomic

responses in 3-year-olds, they enhanced them in 5-year-olds. Finally, Golinkoff,

Shuff-Bailey, Olguin, and Ruan (1995) showed that, when the categories were at

the basic rather than the superordinate level, preschool children showed a convin-

cing enhancement of true taxonomic categorization with names. Thus, although


names may sometimes draw young children's attention to appearances, they also

may sometimes draw their attention away from appearances and to conceptual

kinds.

In light of the mixed messages concerning naming effects from these related

studies of categorization, it would seem wise to further explore the question of

how naming impacts young children's use of functional information in artifact

categorization. We have already seen that 4-year-olds' lexical categorization is

not immune to functional information about the artifacts used in the current studies,

but, without a comparison no-name condition, it is not possible to evaluate whether

the lexical condition is still having a dampening effect. Do names consistently

depress attention to function and enhance attention to appearance, as Smith et al.

(1996) found? Does the effect that they observed generalize to the present artifacts,

designed to have compelling structure/function relations? Does it obtain in children

older and younger than age 3? These are the primary questions addressed in the ®nal

series of studies.

6.1. Experiment 3A

The initial study in the series involved a direct comparison of lexical and non-

lexical conditions in 3- and 4-year-old children. Possibly, naming is less likely to

have a depressive effect in the 4-year-olds since the link between naming and

exclusive attention to shape is said to weaken after age 3 (Smith, 1995). Indeed,

given the sometime ®nding that naming may actually enhance children's conceptual

processing in related contexts, it is possible that naming will actually augment

attention to function in the older children.

In addition to the name/no-name comparison, the current study includes an addi-

tional name group tested under conditions that would seem to be more challenging

for the use of functional information in naming. In the name-inference condition,

children were shown the functions of the standards and encouraged to carry them

out, but then were asked to generalize the names to test objects when the props

necessary for trying out their functions were removed. Taking the functional status

of the test objects into account in this condition requires that the children sponta-

neously infer the functional status of the objects and use that inferred information

when they name. Even in 3-year-olds, Kemler Nelson et al. (1995) found an in¯u-

ence of functional information on naming under these particularly demanding condi-

tions, but in the absence of a no-inference comparison group, it was not clear

whether the requirement to infer had some impact.

6.1.1. Method

6.1.1.1. Participants Participating in the study were 36 3-year-olds, 18 boys and

18 girls, and 36 4-year-olds, 20 boys and 16 girls. The mean age of the younger

group was 3 years 7 months (range 3 years 1 month to 3 years 11 months), and the

mean age of the older group was 4 years 8 months (range 4 years 2 months to 4 years


11 months). The children were enrolled in preschools in an upper-middle-class

suburban area. None had participated in earlier studies of artifact categorization.

6.1.1.2. Stimulus materials. The artifacts were the same as those used in the

plausible-function condition of Experiments 1 and 2.

6.1.1.3. Design. Twelve participants in each age group were randomly assigned to

three different experimental conditions: the name and no-name conditions (also used

in the preliminary study with adults), and the additional name-inference condition.

In all conditions, the children were informed about and had the opportunity to try out

the functions of the standard objects.

6.1.1.4. Procedure. Each child was tested individually in a session that lasted about

15 min. The session began with the introduction of Mr. Rabbit and a warm-up phase

of two trials, in which children classi®ed the trucks and the percussion toys (the

dumples in the name condition), followed by the four experimental trials with the

novel artifacts. The procedure in the warm-up phase was tailored to the participant's

experimental condition such that the transition from warm-up to experimental trials

was seamless. In all conditions, the sequence of events on a single trial consisted of

(a) the introduction of the standard, a demonstration of how it worked, and

encouragement for the child to carry out the standard function three times, (b)

placement of the standard out of reach, but still visible, (c) introduction of the

®rst test object (randomly determined on each trial to be either the functional or

the dysfunctional object), (d) removal of the ®rst test object and introduction of the

second test object, and (e) positioning of the ®rst and second test objects to the right

and left of the child and within reach while the probe for classi®cation was delivered.

In the name and name-inference conditions, the presentation of the standard ((a)

above) was accompanied by the experimenter's using its name several times in

casual conversation. In addition, the probe for classi®cation ((e) above) was

designed to elicit name generalization. For example, the experimenter pointed to

the standard and said, `I'm going to give Mr. Rabbit this ®lsap. Can you help Mr.

Rabbit by giving him the other ®lsap?' The difference between the two conditions

was the availability of the props only for the participants in the name condition when

the test objects were brought out for inspection ((c) and (d) above).

In the no-name condition, there was equivalent talk about the standard object

during its presentation ((a) above), but it was never named. So, for example, instead

of saying, `Let me show you how this ®lsap works', the experimenter simply said,

`Let me show you how this works'. Classi®cation was requested ((e) above) by the

experimenter's ®rst indicating the standard (`I'm going to give Mr. Rabbit this one.')

and asking the child, `Can you help Mr. Rabbit by giving him another one like it?' In

the no-name condition, as in the name condition, the props were available through-

out the trial, so that the child had an opportunity to explore the functional properties

of the test objects ((c) and (d) above).


6.1.2. Results and discussion

Percent choices of the functional object over the dysfunctional (but more similar-

appearing) object are shown at the top of Table 6, separately for each age group and

each experimental condition. An analysis of variance for a 2 (Age) £ 2 (Condition)

design yielded a marginal effect of Age (F�1; 66� � 3:69, P , 0:06), a reliable effect

of Condition (F�2; 66� � 6:28, P , 0:005), and a reliable interaction between them

(F�2; 66� � 6:82, P , 0:002). As determined by Tukey's test (P , 0:05), the criti-

cal difference between cells is 35.2%. Accordingly, the experimental conditions had

a signi®cant differential effect only within the older group, with both name and

name-inference conditions producing more functional choices than the no-name

condition. Furthermore, the 4-year-olds produced reliably more functional choices

than the 3-year-olds in the name-inference condition. No other pair-wise differences

were even marginally signi®cant, including the difference between the name and no-

name conditions for the 3-year-olds and between the name and name-inference

conditions for the 4-year-olds.

Further tests assessed each group's performance relative to chance. Again, the

results were straightforward for the 4-year-olds. These children in both of the name

conditions made reliably more than 50% functional choices (t�11� � 2:30, P , 0:05

and t�11� � 2:93, P , 0:02, respectively). Their function-based naming also

appeared to be relatively consistent across individuals and stimulus sets. In the

two conditions in which a name was provided, 15 children favored functional

choices and only three favored dysfunctional choices. Overall, they chose the func-

tional object 83, 62, 79, and 67% of the time for the beckets, luzaks, vinsels, and

®lsaps, respectively.

In contrast to the older children, the 3-year-olds showed a marginal tendency to

select the functional alternative in the no-name condition (t�11� � 1:82,

0:05 , P , 0:10), and the dysfunctional alternative in the name-inference condition

(t�11� � 2:15, 0:05 , P , 0:10). In both cases, there appeared to be variability

across stimulus sets. In the no-name condition, 3-year-olds selected the functional


Table 6

Percent choices of the functional over the dysfunctional object with standard errors in parentheses

Group Condition

Name-inference Name No-name

Experiment 3A

Four-year-olds 73.0 (7.47) 73.0 (9.52) 37.5 (8.58)

Three-year-olds 33.2 (7.42) 48.0 (11.20) 60.5 (5.48)

Experiment 3B

(no functional

information)

Three-year-olds ± 27.0 (9.05) 27.0 (5.48)

Experiment 3C

Two-year-olds ± 54.2 (5.78) 50.0 (7.80)

object 83, 75, 50, and 33% of the time for the beckets, luzaks, vinsels, and ®lsaps,

respectively. In the name-inference condition, the respective choices of the dysfunc-

tional (but more similar-appearing) object occurred 50, 75, 67, and 75% of the time.

Overall, the results of Experiment 3A are clearest for the 4-year-olds. In contrast

to the effect observed by Smith et al. (1996), naming consistently enhanced (rather

than diminished) their tendency to take function into account in categorization.

Moreover, these children were more likely to generalize names on the basis of

functions than appearances ± as observed previously in the comparable conditions

of the ®rst two experiments.

The picture for the 3-year-olds is different, but it is also less clear. Unlike the

older children, naming did not enhance their use of functional information. The

direction of the difference between name and no-name conditions is consistent

with the depressive effect of naming previously reported in this age group (Smith

et al., 1996), but the difference is not reliable. There is no statistical support for

any effect of naming within the 3-year-olds. Nor is there any solid evidence that

the inference requirement had an impact on them. Still, they used functional

information reliably less than the older children only in the name condition

that required inferences.

6.2. Experiment 3B

The purpose of Experiment 3B was to provide a baseline condition for further

consideration of the results from the 3-year-olds in Experiment 3A. Three-year-old

children were asked to name or otherwise categorize the experimental artifacts

without information about the intended functions of any of the objects, including

the object standards. On each trial, the children were shown a standard novel object,

either named or unnamed, and then simply asked which of two test objects, in

relation to the standard, either got the same name or constituted `another one'. If

functional information was having some impact on how 3-year-olds categorized the

artifacts in Experiment 3A, then in the current study relative to the previous one,

they should show a lesser tendency to generalize to the functional alternative and a

greater tendency to generalize to the more similar-looking, but dysfunctional alter-

native.

6.2.1. Method

6.2.1.1. Participants Twenty-four children attending an upper-middle-class subur-

ban preschool, 13 boys and 11 girls, participated in the study. Their mean age was 3

years 5 months, with a range of 3 years 0 months to 3 years 9 months. None had

participated in an earlier study of artifact categorization.

6.2.1.2. Stimulus materials. The object sets were the same as those used previously.

The props were not present, however.

6.2.1.3. Design. Twelve children, chosen at random, were assigned to a name

condition, and 12 others to a no-name condition.


6.2.1.4. Procedure. Children were tested individually in a single session of about 10

min. The procedure was like that used in Experiment 3A, except that functional

information was not provided at any time. Hence, there were only two conditions,

name and no-name. Any inquiry by a child as to how the objects worked or what

they were `for' was de¯ected by the experimenter's feigning ignorance and

reminding the child that it was her friend who had sent the objects.


The percentages of choices of the functional test object were identical in the name

and no-name conditions (27%) as shown in Table 6. Each of these differs reliably

from the point of indifference (t�11� $ 2:42, P , 0:04), indicating that the children

in both conditions had a tendency to select the dysfunctional objects ± that is, the

objects intended to be more similar to their standards in appearance. This pattern

was relatively consistent across individuals and across object sets. Seventeen chil-

dren favored the dysfunctional alternatives, and only two favored the functional

alternatives; ®ve children were indifferent between them. The dysfunctional object

was selected 79, 62, 75, and 75% of the time for the beckets, luzaks, vinsels, and

®lsaps, respectively.

Since the children in this study were uninformed about the functions of any of the

objects, this tendency to select the dysfunctional object is unsurprising. However, it

does establish that the similarity-of-appearance relations that we had attempted to

arrange in our stimulus sets were successfully realized for the preschool children.

Although adults' direct ratings had suggested this, the children's own responses

provide con®rmation. The same results also establish that the intended functions

of our standard objects were not so transparent that the children spontaneously

inferred them and used them as a basis for categorization. This provides some

empirical justi®cation for our earlier suggestion that the structure/function relations

that typify the current artifacts are more complicated and less familiar than those

arranged by Kemler Nelson (1999).

Most important is to compare the data of the present study with 3-year-olds'

categorizations in Experiment 3A, when functional information was provided.

With the current data now establishing a baseline, is there evidence that 3-year-

olds in Experiment 3A were sensitive to function in categorization, and, if so, were

they differentially sensitive to it in the name and no-name conditions? The numbers

of 3-year-olds' functional choices were submitted to an analysis of variance for a 2

(Functional Information: Available or Unavailable) £ 2 (Condition: Name or No-

Name) design. The main effect of Functional Information was reliable

(F�1; 44� � 10:05, P , 0:01), but there was no apparent effect of Condition

(F , 1:0) nor any hint of an interaction between Condition and Functional Informa-

tion (F , 1:0). The main effect demonstrates that the functional information

provided for the artifacts in Experiment 3A did have some impact on how they

were named and classi®ed by 3-year-olds. Even if choices of the functional object

were not signi®cantly in the majority among these children, they were reliably

greater than in the baseline condition when no functional information was available.

Notably, however, providing functional information seemed to have had the same


effect on the 3-year-olds under the name and no-name conditions, suggesting again

that naming neither enhanced nor depressed their attention to function.

6.3. Experiment 3C

A ®nal test for the effects of naming was carried out with 2-year-olds. Is it

possible that the depressive effect of naming on attention to function, as observed

by Smith et al. (1996), would obtain in still younger children? To ®nd out, the

performances of 2-year-olds were compared in name and a no-name conditions.

6.3.1. Method

6.3.1.1. Participants The participants were 11 boys and 13 girls, with a mean age

of 2 years 6 months, and a range between 2 years 2 months and 2 years 11 months.

They were identi®ed through birth announcements in local suburban newspapers,

and brought into the laboratory by their parents, who had been contacted earlier by

letter and by telephone. Four additional children were eliminated from the data set ±

three because their parents intervened in a potentially informative way during the

session, and one because of fussiness and inattentiveness.

6.3.1.2. Stimulus materials. The materials were identical to those used in

Experiment 3A.

6.3.1.3. Design. Children were randomly assigned in equal numbers to the name and

no-name conditions.

6.3.1.4. Procedure. The procedure was the same as that used in the name and no-

name conditions of Experiment 3A.


The results from the 2-year-old children are shown at the bottom of Table 6.

Both in the name and the no-name conditions, they seem to have divided their

responses about equally between the functional and dysfunctional alternatives.

There is no suggestion that naming had any effect. The difference between the

name and no-name condition is not reliable (t , 1:0), and in neither condition did

functional or dysfunctional choices predominate (t , 1:0 in each case). Accord-

ingly, with the materials that we have been using, 2-year-olds failed to show a

naming effect.

An additional analysis involved a comparison of the 3-year-olds in the name and

no-name conditions of Experiment 3A with the 2-year-olds of Experiment 3C. An

analysis of variance for a 2 (Condition) £ 2 (Age) design failed to provide any

suggestion of either main effect (both F , 1:0) or the interaction

(F�1; 44� � 1:31, P . 0:10). It is certainly clear that the 2-year-olds provided no

fewer functional choices than the 3-year-olds in the name condition, and there is no

reliable evidence that they did so in the no-name condition either. Finally, when the

2-year-olds' data were compared to the 4-year-olds' data of Experiment 3A in a


parallel analysis of variance, there was a main effect of Condition (F�1; 44� � 5:55,

P , 0:01), no main effect of Age (F�1; 44� , 1:0), and a marginally signi®cant

interaction (F�1; 44� � 3:46, 0:05 , P , 0:10). The suggestion of an interaction

is consistent with our previous conclusions that the 4-year-olds made more func-

tional choices in the name than the no-name condition, and the 2-year-olds, like the

3-year-olds, did not.

Overall, the results of Experiment 3 suggest that 2- and 3-year-old children

differed from 4-year-olds. Both groups of younger children appeared to categorize

no differently in lexical and non-lexical conditions, in contrast to the older children,

who clearly used functional information over appearance in a lexical context speci-

®cally. Thus, whereas Smith et al. (1996) concluded that naming depresses attention

to function and augments attention to perceptually salient properties when young

children categorize, we ®nd no convincing supporting evidence with our different

stimulus materials. Indeed, we ®nd a strong reversal of the predicted effect in 4-year-

old children.

Examining all the evidence concerning lexical effects on young children's use

of function to categorize artifacts, one sees many of the same inconsistencies that

have emerged in the larger literature concerning lexical effects on categorization

in young children. Comparing name and no-name conditions, young children are

sometimes more likely to respond in a conceptual manner in the name condition,

other times in the no-name condition, and still other times there is no difference

between them. This is exactly the overall picture for children's use of functional

information. In 4-year-olds we ®nd the tendency to use functional information

more in the name condition, in 3-year-olds Smith et al. (1996) ®nd it more in the

no-name condition, and in 2- and 3-year-olds we ®nd no differential tendency

between conditions. Our own data suggest a developmental effect, with the

advantage for the name condition emerging only in the older children we tested.

However, the comparison between our data and those of Smith et al. (1996)

suggests that age is not the only relevant factor. Even though they did not

privilege it over appearance, our 3-year-olds in the name condition were clearly

in¯uenced by functional information, whereas theirs just as clearly were not.

Moreover, the advantage for the no-name condition over the name condition in

3-year-olds was strong in the Smith et al. (1996) study, but (even by a one-tailed

test) failed to appear reliably here.

We turn to the developmental effect ®rst. A tendency to privilege functional

information over appearance was observed only in the 4-year-olds and only in the

two name conditions. Why should naming enhance their use of functional informa-

tion, and why might the same lexical-facilitation effect not occur in younger children

tested under comparable conditions?

As to the facilitative effect of naming, one possibility is that naming prompts more

conceptual processing in 4-year-olds, and a concomitant tendency for their categor-

ization to be drawn away from the competing pull of super®cial appearances. In a

related vein, the experimenter's query in the lexical condition creates a clear request

for categorization, whereas the query in the non-lexical condition is a good deal

more ambiguous. After all, one can sensibly select `another X like this X' on the


basis of similarities other than common category membership, and the 4-year-olds

seemed to have done so at least half the time. Quite possibly, from the 4-year-olds'

point of view, the no-name condition does not create a demand for categorization at

all.

Given this speculation, it may be somewhat surprising that a name versus no-

name difference did not occur also in the younger children. However, their tendency

to take functional information into account in the name condition(s) appeared to be

weaker than the 4-year-olds', and this may be a large part of the explanation. To be

sure, a developmental difference in the use of functional considerations has not

always been obtained in earlier comparisons of 3- and 4-year-olds (Kemler Nelson

et al., 1995). Still, the lack of previous age differences is likely to be due to the

simpler and more familiar structure/function relations embodied in the experimental

artifacts that were tested. Indeed, even 2-year-olds sometimes privilege function

over appearance when the structure/function relations are made still simpler

(Kemler Nelson, 1999; Kemler Nelson et al., in press). In contrast, it is plausible

that for the more complicated artifacts used here, 4-year-olds may have been in

better command than 2- and 3-year-olds of the background knowledge necessary to

discern how object structures afforded object functions, providing a stronger

impetus for the older children to attend to functional information when they

named them.

We turn ®nally to the discrepancies between the Smith et al. (1996) ®ndings

with 3-year-olds and our observations of 3-year-olds in the current experiment.

Two inconsistencies are notable. The ®rst is 3-year-olds' sensitivity to functional

information when they named our artifacts, as opposed to their total immunity to

it when they named the artifacts designed by Smith et al. (1996). The second is

the apparent lack of any lexical effect on 3-year-olds in the current study, as

opposed to the depressive effect of naming observed by Smith et al. (1996). With

regard to both, the results of Experiments 1 and 2 may be of heuristic value. As

noted previously, the relations of structure and function within the artifacts of

Smith et al. (1996) would seem to have been less compelling than those arranged

here, possibly leading their children to be less likely to believe that the demon-

strated functions revealed the intentional origins of the categories. In addition,

there may have been more time pressure on their children to make their naming

decisions. Either or both factors may have undermined 3-year-olds' use of func-

tion when naming. If so, then the observation by Smith et al. (1996) of more

functional categorization in the no-name condition may have been attributable to

their children taking the demonstrated functions to be a convincing source of

object similarity (tapped in the no-name condition), but a less convincing source

of artifact category membership (tapped in the name condition). It is also concei-

vable that their no-name instruction, which explicitly requested comparisons

between the test objects and the standards, may have slowed down responding

relative to their name condition in which no such comparisons were prompted.

Whatever the explanation, it would seem that the advantage of the no-name

condition reported by Smith et al. (1996) is not a general ®nding in 3-year-

olds, does not seem to occur in 2-year-olds, and seems to reverse in 4-year-olds.


7. General discussion

The experiments reported in this paper systematically identify three variables that

in¯uence the degree to which 4-year-old children categorize artifacts according to

their functional properties rather than their overall appearances or their shapes. The

variables shown to matter are: (1) whether or not the demonstrated functions of the

artifacts are plausible as causal explanations of their physical structures, (2) whether

or not the children can generate their responses in an unhurried manner, and (3)

whether or not categorization is tested in a lexical context. A variable that does not

seem to matter to 4-year-olds is whether they have the opportunity to perform the

functions of the test objects when they generalize the name. The ®nal experiment

also indicates that a naming context, previously shown to inhibit function-based

categorization in younger children, not only can have the opposite effect in 4-year-

olds, but may sometimes have no detectable effect in either direction in 2- and 3-

year-olds.

The current studies afford two types of conclusions. Most immediately, they

provide experimental tests relevant to several hypotheses that have been offered

speculatively in the earlier literature about when young children do and do not take

function into account when they categorize artifacts. Below, we enumerate these

proposals, indicating ®rst those that receive support in the present work and then

those that do not. Then, drawing on these speci®c assessments, we address the larger

issue of how best to characterize the mechanisms underlying function-based cate-

gorization when it occurs in young children.

7.1. Proposals that receive support

1. Categorization by function is more likely to occur when the function helps to

make sense of the artifacts' structures. Experiment 1 showed that when the

functions that were demonstrated for the artifacts were not convincing accounts

of why the objects had the kinds of perceptual properties they did, young children

were a good deal less likely to privilege functional information over shape or

overall appearance as a basis for generalizing an artifact name.

2. Categorization by function is more likely to occur when children are not pressed

to respond impulsively. Experiment 2 demonstrated that function-based naming

was more likely to occur, and appearance-based naming was less likely to occur,

when young children generated names slowly and deliberatively, as opposed to

rapidly and unre¯ectively. This makes sense on the view that children's function-

based naming entails conceptual processing, given the common assumption that

conceptual processes are slower than perceptual processes.

3. Categorization by function is more likely, the older the child. As shown in

Experiment 3, there are conditions under which older preschool children were

more likely than younger preschool children to use function as the basis for

naming artifacts. For the current objects, naming by function over appearance

occurred only in the 4-year-olds, although 3-year-olds' naming was not immune

to functional in¯uence.


4. Naming may lead to more function-based categorization than a non-naming

condition. Still, the effect of the lexical variable is not simple; it seems to interact

with some of the aforementioned factors ± particularly age. For the 4-year-olds,

but not the younger children of Experiment 3, the lexical context enhanced the

children's tendency to take function into account when they categorized.

7.2. Proposals that do not receive support

1. Categorization in¯uenced by function is a rare event in young children. Although

there is almost a consensus in the existing literature that this hypothesis is correct,

the ®ndings from the three experiments presented here, using four new sets of

artifacts, add to accumulating evidence that its validity has been overestimated.

Perhaps, in an effort to design novel artifacts that are suf®ciently simple to be

easily constructed for the laboratory and that pit function against shape or appear-

ance in the most straightforward ways, investigators have had an inadvertent

tendency to create experimental object sets that do not mimic the typically

compelling structure/function relations of real artifacts. If so, the ®ndings from

Experiment 1 suggest why young children have not been likely to categorize

these objects by function.

2. Categorization by function in young children depends on overlearned, pre-

experimental, re¯ex-like associations between familiar functions and familiar

object parts. It is dif®cult to see how this hypothesis could explain the tendency

of 4-year-olds to privilege functional considerations, or the tendency of still

younger children to take them into account, when they categorized the artifacts

used in our experiments. Generally, the functions for which these objects were

designed were relatively unfamiliar and were afforded by particular relations

among relatively unfamiliar object parts (rather than the mere existence of famil-

iar parts). In addition, the results of Experiment 2 would seem to undermine the

idea that functional categorization by young children is automatic and re¯ex-like.

3. Naming depresses the likelihood of categorization by function in young children.

The only reliable effect of naming in Experiment 3 was to enhance function-

based categorization by 4-year-olds, the antithesis of the effect predicted by this

hypothesis. Although 2- and 3-year-olds did not show the same enhancement

from naming, neither did they show the predicted reduction.

4. Categorization by function in young children is based on sensori-motor general-

ization. The results of Experiment 1 showed that when the plausibility of the

structure/function relations was undermined, function-based categorization was

disrupted even though action-based generalization was not. The children could

still perform the implausible function with the functional test object, and not with

the dysfunctional test object. Moreover, when action-based generalization was

blocked in the name-inference condition of Experiment 3, 4-year-olds showed no

lesser tendency to categorize by function, and the effect of requiring an inference

on 3-year-olds was not reliable. In fact, using simpler artifacts, Kemler Nelson et

al. (1995) showed that function had a strong in¯uence on how 3-year-olds


extended a novel name when such inferences were required. Still, for children

under the age of 3, it may be premature to dismiss the importance of action-based

name generalization as the mechanism underlying attention to function (Kemler

Nelson et al., in press; Nelson, 1973).

7.3. The nature of artifact categorization by young children

Overall, the current results underwrite a compelling argument that, at least by the

time they are 4 years old, and quite possibly before (Kemler Nelson, 1999; Kemler

Nelson et al., 1995, in press), the categories underlying young children's names for

artifacts may be conceptually saturated, and the processes by which children learn

and extend names for artifacts, mindful and inferential. Such a conclusion contrasts

dramatically with a prevailing view that children's artifact categories are wholly or

largely organized around salient perceptual properties, perhaps especially shape, and

that the processes by which children learn and extend artifact names are usually

mindless and re¯exive (Landau et al., 1998; Smith et al., 1996). The ®ndings from

all three experiments that we have presented seem compatible with the ®rst view and

incompatible with the second. Four-year-olds have been shown to weigh functional

information more when it supports a causal account of object structure, to give it

more weight when allowed time to actively explore and deliberate, and to weigh it

more when generalizing a name as opposed to merely judging similarity. Moreover,

in all these cases, weighing functional information more is complemented by weigh-

ing similarity in shape and/or overall appearance less.

In the domain of artifacts, we have argued, the function intended by the designer

is the criterion that adults use for discerning kind membership and the extensions of

basic-level names. Learning new names, the 4-year-old children in our studies, too,

understand them to refer to conceptual kinds as opposed to perceptual classes.

Importantly, they not only take account of function when they name, but they

weigh functional information more or less depending on its credibility as the inten-

tional cause of object design. They not only generalize names according to func-

tional considerations, but they do so even when the functions of the objects to which

they extend them must be spontaneously inferred. Hence, the picture of the 4-year-

old categorizer that emerges from the current work is that of an active reasoner and

problem-solver (Murphy & Medin, 1985) ± perhaps even that of a theorist (Bloom,

2000; Gopnik & Meltzoff, 1997; Wellman & Gelman, 1992).

How early in development might this characterization apply? There are sugges-

tions in the current work that 2- and 3-year-olds are less likely than 4-year-olds to

privilege function over appearance when they name. Yet, there is also evidence from

our 3-year-olds that function has some impact on their categorization, and there is no

indication at any age we tested that appearance similarity or shape similarity domi-

nates as long as functional information is provided. In addition, it is known that with

different artifacts, for which the relation between structure and function is likely

simpler to understand, function sometimes plays quite a powerful role in naming by

children under the age of 4 (Kemler Nelson, 1999; Kemler Nelson et al., 1995, in


press). It remains to be seen whether or not the manipulation of function/structure

compellingness of Experiment 1 or the manipulation of response tempo of Experi-

ment 2 would have effects on younger children parallel to those we observed in 4-

year-olds. Still, the results of Bloom and Gelman (2000), Bloom and Markson

(1998), and Gelman and Ebeling (1998) show that 3-year-olds, and even to some

extent 2-year-olds, reason about human intentions when they name, so that effects

parallel to the ®ndings of Experiments 1 and 2 in such younger children are not out

of the question.

Although developmental differences were not our primary focus, the present

perspective on artifact categorization raises the possibility that multiple factors

may be relevant to whether and when developmental differences obtain in how

children name functional artifacts. It follows naturally from our conclusions that

the speci®c nature of the artifacts should be particularly important. To the extent that

even the youngest of the children can make sense of the structure/function relations

that are relevant, developmental differences could be minimal. But if the older

children are in a better position to make sense of these relations ± either because

they are more familiar with the category itself, or, in the case of a novel category,

because they know more about the mechanisms of physical causality that mediate

between function and structure ± then developmental differences would be expected.

Beyond such category-speci®c considerations, there could also be more general

sources of age differences. Possibly, given their greater experience, older children

may know more about how artifact names generally work. They may be more secure

in their knowledge that functional considerations are primary and that appearances

may be deceiving. They also may be more likely to consider the role of human

intentions, and to evaluate ± more effectively or more often ± the plausibility that a

current function is intentional. As a result, older children also may have a general

tendency to name artifacts ± novel artifacts in particular ± more slowly and re¯ec-

tively. In short, developmental differences could relate to what children know about

human-made objects, but they could relate as well to what children know about

human designers. Notably, the present investigations suggest that, by the age of 4,

they may know a surprising amount about both.

Acknowledgements

Support for this work was provided by Swarthmore College as Faculty Research

Grants and a sabbatical leave award to the ®rst author, and as Joel Dean Summer

Research Assistant Grants to A. Franken®eld and C. Morris. We gratefully acknowl-

edge the ingenuity and craftsmanship of Don Reynolds who helped design the

stimulus materials and who masterfully constructed them as ®nished, real-looking

artifacts. Thanks also to Elena Rosenbloom and Anoosheh Moghbeli for assistance

in the collection of some of the data, and to the staff and children of Swarthmore

Presbyterian Nursery Day School, Swarthmore Friends Meeting Nursery School,

Trinity Cooperative Day Nursery, and the Thorne Nursery School, who participated

in the studies. Finally, we thank several members of a monthly discussion group


(MLU) who provided helpful comments on an earlier draft of this paper. Some of

these data were reported at the Meetings of the Society for Research in Child

Development, Albuquerque, NM (April, 1999), and others at the Boston University

Conference on Language Development, Boston, MA (November, 1999).

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