eight reasons to doubt the existence of a geometric module nora s. newcombe temple university
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Eight Reasons to Doubt the Existence of a Geometric Module
Nora S. Newcombe
Temple University
When Sociobiology Met Cognitive Psychology Modular mind
Adaptive pressure works to select specific mental abilities Massive modularity Core knowledge
Innateness These evolutionarily-selected modules are
(naturally) innately specified
Swiss Army Knife Analogy “The Swiss Army knife is a flexible tool
[because] it is a bundle of tools, each well-designed for solving a different problem – scissors for cutting paper, corkscrew for opening wine, toothpick for cleaning teeth…..Similarly, the human mind … contains a large number of programs, each well-designed for solving a different adaptive problem: choosing a good mate, caring for children, foraging for food, avoiding predators, navigating a landscape, forming coalitions, trading, defending one’s family against aggression, and so on”—Leda Cosmides
Innately-Specified Modules Have Proliferated
Language acquisition Face processing Theory of mind Cheater detection Geometric module
What Do We Mean By Modularity? Modular cognitive systems are domain specific,
innately specified, hard wired, autonomous, and not assembled. Fodor (1983, p. 37)
Neural Specialization Does Not Entail Encapsulated Modularity
Brain areas generally need to ‘talk to’ one another to support a function
Case Study of the Geometric Module A representation of geometric information that
guides reorientation following disorientation That does NOT use nongeometric information
even when doing so would be advantageous
Hermer & Spelke (1996): Search Rates for Toddlers
White Room
F C
R N
F C
R N
C = CorrectN = Near
R = ReversalF = Far
.08
.49
.31
.12
.10
.39
.39
.12
Hermer & Spelke: Search Rates for Adults
White Room
F C
R N
F C
R N
C = CorrectN = Near
R = ReversalF = Far
0
.04
.96
0
.02
.41
.57
0
Language-as-Bridge Hypothesis Adults may have a further system of representation
that is uniquely human and that emerges over the course of development. This system may connect to many other systems of representation, regardless of their domain-specific content. Its operation may be governed by rules and principles allowing the arbitrary combination of information from distinct, domain-specific sources….The language faculty appears to have all the right properties to serve as this uniquely human combinatorial system of representation. --Hermer-Vazquez, Spelke & Katsnelson (1999, p. 34)
Support for Role of Language Transition to feature use at 6 years is
correlated with productive use of left and right
Training left and right leads to feature use Adults who do linguistic shadowing task
concurrently do not use features
Adaptive Combination Models Various sources of spatial information
Ego-referenced: response learning and path integration Allo-referenced: cue learning, place learning
Weighting depends on Salience Certainty and variability with which information is
encoded Validity
probabilities of finding objects given use of the information, derived from interaction with the environment
Weighting develops both in real time and in developmental time
Point 1: Evidence Against Encapsulation from Non-Human Animals Monkeys use colored
walls and large but not small features (a sensible choice given likely cue validity)
Other species Chickens Pigeons Fish
See Cheng & Newcombe, PBR 2005, for review
46 % 4.7 %
3.3 % 46 %
75 % 3.5 %
1.5 % 20 %
Without cue With cue
Point 2: Featural Cues Are Only Neglected in Tiny Rooms
-100
102030405060708090
100
Larger Room Small Room
Toddlers
3-4 Years
5 Years
6 Years
Adults
Cheng & Newcombe(Psychonomic Bulletin & Review, 2005)Note: Perfect Performance = 100
Point 3: Use of Features Varies for Several Reasons
Activity Active motion focuses spatial attention Active motion leads to remodeling of
hippocampal firing
Nature of landmarks More distal landmarks provide more useful and
ecologically valid information Larger landmarks may be more salient and
more likely to be stable
Room Within Room Studies Small waist-high
enclosure (Hermer-Spelke size) centered within “large” room (Learmonth et al. size)
Large room had one colored wall
Children stay within small enclosure
Learmonth, Newcombe, Sheridan & Jones (Developmental Science, 2008)
How the Data Fit An Adaptive Combination Model
Distal Action Target Proximal Age at SuccessFeature? Possible? to Feature?
Hermer-Spelke No No Yes 6 years
Learmonth Yes Yes Yes 18 monthset al. (earliest tested)
Study 1 Yes No No 6 years
Studies 2 & 3 Yes No Yes 4 years
How the Data Fit An Adaptive Combination Model
Distal Action Target Proximal Age at SuccessFeature? Possible? to Feature?
Hermer-Spelke No No Yes 6 years
Learmonth Yes Yes Yes 18 monthset al. (earliest tested)
Study 1 Yes No No 6 years
Studies 2 & 3 Yes No Yes 4 years
How the Data Fit An Adaptive Combination Model
Distal Action Target Proximal Age at SuccessFeature? Possible? to Feature?
Hermer-Spelke No No Yes 6 years
Learmonth Yes Yes Yes 18 monthset al. (earliest tested)
Study 1 Yes No No 6 years
Studies 2 & 3 Yes No Yes 4 years
Point 4: Featural Cue Use is Easy to Get When Lacking
Room within Room Switch-No Pen: 3 Years
67.71
20.83
4.177.29
0
10
20
30
40
50
60
70
80
90
100
Correct Opposite Near Far
Box Selection
% o
f possib
le in
sta
nces t
his
box
was s
ele
cte
d
1st 4 Trials2nd 4 Trials
Learmonth, Newcombe, Sheridan & Jones (Developmental Science, 2008)
Similar finding: Twyman, Spetch & Friedman, (Developmental Psychology, 2007)
F C
R N
.06
.33
.52
.10
Point 5: Spatial as Well as Verbal ShadowingReduces Feature Use in Adults
Ratliff & Newcombe, Cognitive Psychology, 2007Also--Hupbach et al., Spatial Cognition & Computation, 2007
Usual results with white room and with colored wall but no
concurrent task
*
Point 6: New Evidence from Conflict Paradigms When features are moved, subjects must
choose a location based either on features or on geometry
These paradigms reveal the fundamental similarity of human adults to children and non-human animals Ratliff & Newcombe, Psychological Science, 2008
Conflict Procedure “There are four hiding spots in this room, one at each corner”
“I will hide a pair of keys in the same place every time”
► 4 practice trials (target & landmark stable)► Leave the room► Brief delay ~ 2 minutes (drawing task)► While the participant waits outside, the
experimenter goes back into the room to move the landmark clockwise to the next adjacent wall
► Two conflict test trials
Conflict Procedure
Where are the keys?
A D
B C
Experiment 1N = 32 TRAINING (Between Subjects) TESTING
Direct Landmark
Indirect Landmark
E G
G L
E
G
G
L
Small room (4x6ft) n = 8
Small room (4x6ft) n = 8
Large room (8x12ft) n = 8
Large room (8x12ft) n = 8
(Landmark = L, Geometrically appropriate = G, and Error = E)
Adaptive Combination Predictions When forced to choose one cue over the other
(geometry vs. features), conflict test will result in a room size effect Distal landmarks are more valid in the larger room
Corners related to feature cues will be more likely to be chosen in the larger room
Geometric cues are more salient in the smaller room Geometric cues will be chosen most often in the smaller
room
Significant Room Size effect (p < 0.01) Geometric information guided reorientation in the small room Features guided reorientation in the larger room
LARGE ROOM TRAINING & TESTING
SMALL ROOM TRAINING & TESTING
E .43 (.06)
.19(.05)
.38(.06)
0
G
L G
E
.16 (.04)
.56 (.06)
.28(.06)
0 G
L G
(Landmark = L, Geometrically appropriate = G, and Error = E)
Results
Experiment 2 How does prior experience impact feature use in a
conflict situation? Replicates experiment 1 but switches room sizes
between training and testing Predictions:
Replicate no effect of landmark location (direct/indirect)
Training in the larger room will increase feature use among adults reorienting in the small room
Cross-experiment comparisons: Significant effect of training Feature use increased in small room testing from Exp. 1 (small
room training) to Exp. 2 (large room training)
(Landmark = L, Geometrically appropriate = G, and Error = E)
Results
E .10 (.04)
.81 (.04)
.10 (.04)
0 G
G
SMALL ROOM TRAINING/LARGE ROOM TESTING
L
LARGE ROOM TRAINING/ SMALL ROOM TESTING E
.03(.02)
.94(.03)
.03(.02)
0
G
L G
Conclusions Feature use is not associative:
No effect of feature location (direct vs. indirect) in Exp 1 or 2
Experience is important As expected, large room experience boosts feature use for the
small room test
Reorientation depends on process of combining weights associated with features and geometry Not simply relying on the most salient cue Although the conflict procedure does not allow direct
assessment of combination
Point 7: Geometric Information May Be a Special Case of Relative Information
The modularity position predicts failure to reorient in the absence of geometric information
Is reorientation a more general discrimination of relative quantity task?
Huttenlocher and Lourenco, 2007 Non-relative Cues
Non-geometric, Relative Cue
Multiple cues Area, spatial density, and number
Nominal versus ordinal scale “Cues which specify order along a magnitude
scale (more, less) may be more easily mapped onto spatial position (left, right) than two distinct unordered properties (red, blue) which are mapped separately onto spatial position” (Huttenlocher & Lourenco, 2007)
Why Might Relative Cues Be Easiest?
Since the initial claims of modularity were made from animal research…
Will mice replicate this pattern of results?
Is This Pattern True Across Species?
C57 mice – 4 per group
Non-geometric
Relative Cue
Non-geometric
Non-Relative
Non-geometric
Non-Relative
Results: AccuracyTwyman, Newcombe & Gould, J. Comparative Psychology, in press
Small - Large 81%
Yellow - Blue 69%
Dots - Gray 69%
Even though there is a trend for the relative cue group to be more accurate, there were no significant differences between groups
Results: Trials to CriterionTwyman, Newcombe & Gould, J. Comparative Psychology, in press
Small versus Large 12 trials (0.00)
Yellow versus Blue 38 trials (5.77)
Dot versus Gray 33 trials (6.81)
The small-large group learned the task significantly faster than either the yellow-blue or the dot-gray group.
Point 8: Use of Features is NOT Merely Associative One might have thought 7 points were enough
—but the modularity theorists have a comeback--
The Module Strikes Back Lee, Shusterman &
Spelke (2006) argue that—
Search behavior following disorientation depends on two distinct processes: a modular reorientation process…and an associative process that directly links landmarks to locations (p. 581)
Return of the Jedi Problems with Lee et al.
Small moveable landmarks Defining quite small area
Alternative way to test the two step hypothesis Use of colored wall in an octagon with
alternating short and long sides to discriminate among 3 all white corners
The Octagonal Space
BD
A
C
Photo of the Octagon
Starting with An All-White Octagon
Questions Can children use geometry in a more complex figure?
YES if total GC choices > 50% Can children use geometry in a figure without an axis of
principal symmetry? YES if total GC choices > 50%
Methodologically, have children been successfully disoriented? YES if correct choice NOT > average of other
GC choices
Data from All-White OctagonNewcombe et al., Developmental Science, in press
0
50
100
2yr
3yr
TotalGCChance 0
50
100
2yr
3yr
PC
MeanGC
At left, we see that both 2- and 3-year-old children were reliably greater than chance in choosing geometrically correct corners
At right, we see a slight and non-reliable ability to choose the correct corner from among the 4 geometrically correct corners
Data from Octagon with Colored WallNewcombe et al., Developmental Science, in press
0
50
100
3yr
5yr
TotalGCChance 0
50
100
3yr
5yr
PC
MeanGC
At left, we see that both 3- and 5year-old children were reliably greater than chance in choosing geometrically correct corners
At right, we now see a reliable ability to choose the correct corner from among the 4 geometrically correct corners
What About the Targets in All-White Corners?
Correct choices reliably greater than average of other GC corners 35% versus 14% at 3 years 38% versus 10% at 5 years
These data show that young children do in fact use features to reorient
Can Children Use Features ALONE?Newcombe et al., Developmental Science, in press
XX
XX XX
On these 2 conditions, children averaged 50%, reliably greater than chance (33%)
In this condition, children averaged 64%, reliably greater than chance (50%)
Three Hiding Boxes Two Hiding Boxes
Specific Conclusions Strong evidence for coding of geometric information Little evidence for an encapsulated geometric module or
the role of language in puncturing it Good evidence that different types of spatial information
are routinely (though not invariably) combined Combination process depends on
Cue salience Encoding variability and certainty Acquiring information on cue validity through action
and experience
General Conclusion We can analyze
spatial navigation and orientation as an evolved mental skill without postulating Encapsulated
modularity Highly specific
innate endowment
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