Verbal Behavior

An Operant Perspective

Defining language and verbal behavior

• Language typically refers to linguistic behavior• By definition, must have several functions

– Uses symbols, syntax and semantics– Used to get access to items/activities– Can be used to stimulate additional symbols– Can be used to prompt social behavior from others

• Verbal behavior:– Skinner– Deals with performance of a speaker and the environmental conditions

that establish and maintain verbal performance– Focus on the FUNCTION of the verbal behavior, not the form of the

language

Basic Distinctions for Verbal Behavior

• Verbal behavior = – vocal, written, signed behavior of a speaker, writer or

communicator– Behavior operates on the listener, reader, or observer– Reinforcement of verbal behavior occurs in particular

settings

• Allows the communicator to affect environment indirectly, as opposed to nonverbal behavior (which has a direct effect)

Range of Verbal Behavior

• Verbal Operants include– Speaking– Signing– Writing

• Function of the speaker functionally different from behavior of listener– Rule-governed behavior = listener– Verbal behavior = speaker

Rule Governed Behavior

• Refers to effects of words in form of – Instructions– Advice– Maxims– Laws of listening

• Rules = complex discriminative stimuli– Principles that govern sD’s govern stimuli that

control behavior of listener

Verbal Behavior• Govern behavior of speaker

• Verbal behavior is mediated by actions of others

• Way a person speaks is shaped by consequences from the listener

• Reinforcement shapes– Style of speaking– Dialect– Tonal quality– Words used– Word structure, etc.

• All speakers = part of a verbal community– Practices of a cultural/linguistic group– Verbal behavior established and maintained by reinforcing practices of one’s verbal

community

How does Verbal Community control social use of words?

• Social reinforcement shapes the way that speakers use words– Words don’t have own unique meaning, but only meaning

given by verbal community

– What we say = function of social contingencies involving effects/consequences arranged by members of our verbal community

• Long range consequences of speech/word use = access to social and economic resources

Types of social word use

• To establish facts, persuade others: use words to give accounts of own or others’ actions

• Attributions = verbal strategies to persuade others of your current state– I am sad access to comfort

– Use as evidence or to prevent challenges to “factual” statements

– Use words to support actions

– Use words to gain access to social reinforcement:• Good behavior, then words that emphasize dispositional• Bad behavior, then words that emphasize situational

Operant Functions of Verbal Behavior• Two broad operant categories of verbal behavior

– Mands– Tacts

• Mands, or manding, =– Class of verbal operants whose form is regulated by establishing

operations

– Deprivation states, fear or aversive states

– Use to gain access to solutions to establishing operations:• May I have a glass of water resolves thirst when get water• Stop scaring me avoid fear stimuli• Buy this toy for me gain access to toy

Operant Functions of Verbal Behavior• Tacts or tacting

– Class of verbal operants whose form is regulated by nonverbal discriminative stimuli and maintained by generalized conditioned reinforcement in verbal community

– Descriptions of the environment, other facts

– Use to gain access to generalized conditioned reinforcement• The sun is yellow; grass is green• Reinforced by the verbal community (teacher says, “That is correct”)

• Look at function of the verbalization to determine if it is manding or tacting– Often manding hides as tacting– “You look wonderful tonight”- description or gaining access to something?

How can we train Mands and Tacts?

• Manding relations:– Use conditioned establishing operation (CEO):

• Blocked response CEO: impede response by blocking access to a stimulus or event

• As child reaches for cookie- prompt “cookie”; only gets the cookie if make the correct mand (sign or verbalization of “cookie”)

– Can make these very complex: e.g., our test is a series of mands:• “define reinforcement”• Only gain access to points if use correct words to answer the question

– Can also mand to make things go away (negative reinforcement) or to avoid/reduce punishment

How can we train Mands and Tacts?

• Tacting relations:– Speaker must emit a verbal operant whose form depends on nonverbal discriminative

stimulus AND operant class should be acquired and maintained by nonspecific reinforcement

– Nonspecific reinforcement = reinforcer for one response exerts no stimulus control over the form of the next response

– Thus: can use food reinforcement as long as it does not set the occasion for a subsequent verbal response or the selection of the next stimulus• E.g., identification of pictures: shown a picture of a tiger, say tiger, get food reward• The food reward does elicit another dependent response

• Learning to name objects or describe relationship between objects = form of tacting

• Manding training facilitates acquisition of tacting, but not vice versa

Complex verbal relations

• Intraverbal relations:– Class of verbal operants regulated by verbal

discrmininative stimuli

– Verbal stimuli elicited by verbal stimuli• E.g., counting: one, two _______

– Answers to questions: “I went out to eat today”, “oh, where did you eat?”

– Relatively finite set of appropriate (reinforced) responses

Complex verbal relations

• Autoclitic relations– Form of verbal behavior that modifies the consequences produced by other verbal

responses

– Used to exert control by a nonverbal stimulus over the speaker’s tact

– Five categories:• Descriptive: What color is that?• Qualifying: Do you think this is enough rice?• Quantifying: Put a place setting for each person, please.• Manipulative: I will give you a cookie if you say you love me!• Relational: Which one of these matches that one?

• Controlled by motivating operations (MO): make it reinforcing for the speaker to modify the mand, thus increasing control over listener behavior

• Get me water vs. Could you please get me some water• Addition of “please” increases likelihood of listener bringing the speaker water

Echoic vs. Textual relations• Intraverbal relations:

– Class of verbal operants regulated by verbal discrmininative stimuli– Verbal stimuli elicited by verbal stimuli– E.g., counting: one, two _______– Answers to questions: “I went out to eat today”, “oh, where did you

eat?”

• Point-to-point correspondence between stimulus and response defines echoic vs. textual relations– Defined by formal similarity:– requires that the verbal stimulus and the product of the response be in

same modality and have exact physical resemblance– Counting with 1:1 correspondence

Echoic vs. Textual relations

• Echoic: class of verbal operants regulated by a verbal stimulus in which there is correspondence and formal similarity between stimulus and response – this is a dog, say dog; dog– imitation

• Textural: – No formal similarity between the stimulus and response– Reading out loud: not naming the letters, but the letter

combination creates a unique word.– Silent reading assumes that there is textural relations, but the

verbalization has become silent

Matching to Sample and Language

Is metacognition or metalinguistic awareness necessary?

Language• Words act as symbols

• Verbal humans can– Manipulate symbols– Map words onto internal concepts– Use words to “refer” to objects, events, relations

• Behavioral perspective:– Meaning of word established through direct contingencies embedded in

interactions with verbal community– Contingencies largely social

• Symbols = discriminative stimuli– Symbols = stimuli that are “thrown together” with other stimuli– Is bidirectional!

Equivalence Class• Three defining relations:

– Reflexivity: • generalized identity matching• Matching novel stimulus to itself

– Symmetry• Functional reversability of conditional relation• If A then B; if B then A• Occurs without direct reinforcement

– Transitivity• Three stimuli: A, B, C• A = B• A = C• Therefore, B = C

Equivalence Class• Stimulus equivalence:

– Symbol and referents form functionally substitutable elements– Relation between symbol and referent not unidirectional– Deal with verbal or symbolic activity– Picture of a dog = word dog = picture of a dog

• Many animals show stimulus equivalence– Monkeys– Chimps and bonobos– Parrots– Dogs – Pigeons to lesser degree– Sea animals

• What cognitive abilities are necessary for this?

How test “concept formation”

• Concept = – problem solving strategy that is based on relations between

stimuli – NOT strategy based on particular aspects of individual

problems– Start with # of exemplars then applied to novel problems

• Use matching to sample– Shown an exemplar– Pick the matching concept from stimulus array– Sameness-different-ness

Testing animals for Concepts

• Several important criteria for testing across species:– Exclusion effect: novel vs. familiar

• Correct answer = novel stimulus• Are you shaping “choose the new” or “choose the concept”?

– Effects of novelty:• Can be disruptive• Is it the stimulus or the novelty that the animal is responding to?• Using large pool of stimuli helps reduce this effect

Pigeons:• Maki and Hegvik (1980) directed forgetting– Assume that updating of memory is critical– Human data suggest that this depends on

mnemonics

• Directed forgetting = cueing what to forget

• Can animals do this?– Use MTS task again– Now add a delay: DMTS

Pigeons:• Method:

– 6 pigeons– 3 key conditioning chamber; Center key lights up white; peck it

– Peck would then result in one of two equally probable events:• 2 sec access to grain• 2 sec with no stimuli presented

– Used different delays: 6-15 seconds

– Then 2 keys light up: Red and Green• Red reinforced if trial begun with NO food• Green reinforced if trial had begun with NO stimulus presented• Had to remember first event: if correct, got food; if incorrect, got

TO

Training• Training:

– Group “light”: • comparison stimuli omitted for trials containing the house

light during delay• Cue to remember : dark• Cue to forget: light on

– Group “dark”: • comparison stimuli omitted for trials containing NO house light during

delay• Cue to remember: Light• Cue to forget: Dark

– Ran probe tests on last 20 days: Total of 40 F-cue and 40 R cue probe trials

Results for early Pigeons

• Obtained Mean percentages correct for F (forget) cue and R (remember) cues, dark and light, and short or long delays

• Results: – Decrease in matching accuracy in F-cue probe trials relative

to R-cue trials for both Part A and Part B training• Remembered less when cued to forget!

– R-cue trials were more accurate than F-cue, particularly when F-cue was house light and not darkness

Experiment 2

• Examined effects of cuing and the predicted time course of cuing

• Also examine feature positive vs. feature negative effect

• Method:– 6 birds again– Trained on basic task with no delay– Trained to flashing vs. steady houselight– Trained to dark vs. light– Added probe trials

Results of Exp 2 with pigeons

• Again, performance during house light as cue for forgetting was worse compared to house light as cue to remember

• Matching following forget cues was less accurate than following remember cues

• Delay decreased performance

• Presence of House light as forgetting cue was disruptive!

Conclusions:

• Cuing effects can vary with nature of to-be-remembered sample (remember the feature negative effect!).

• Did NOT support the rehearsal hypothesis, but appears pigeons “did something else” when prompted to forget

• Suggests must engage in mediating behaviors to maintain remembering

Memory without Awareness in Pigeons?

• Metamemory?– People can report state of memories, don’t know if animals can– Why is reporting on memory important?

• Adaptive• Provides functional guide to how to remember• Memory monitoring = form of Memory awareness

• How test metamemory:– Test of sensitivity to memory strength: choose whether to take a memory test

• Rejecting the test = less reward than taking test

– Used Direct test of memory (DMTS)– Animals with strong memory awareness should choose to take test more often

• Who has shown metamemory– Humans– Monkeys– Other primates– Dogs– Rats!?!– Now test pigeons!

Metamemory experiments

• Several experiments with 3 pigeons

• Exp 1: birds chose between fixed small # of pellets and varying probabilities of larger # of pellets– Fixed = escape: nNO test– Variable = larger reward for remembered or none for miss (error)

• Over time all birds chose constant reinforcer and switched away from higher variable payoff– No differences in memory– Just a difference in preference

Metamemory experiments in pigeons• Experiment 2:

– Trained on task, then tested memory: – Given the option of a test or no test – If chose no test got an easy discrimination task rather than time out

• Examined choice and accuracy during choice testing vs. forced trial testing– Predicted that less memory = easy discrimination choice when had choice

• Results:– No effect on memory: all pigeons remembered regardless of forced or

choice test– Found longer delays = poorer performance regardless of forced or choice– Pigeons still preferred to not take the test!

Metamemory experiments in pigeons• Exp 3:

– Now present choice to escape simultaneously– Again examined forced vs. choice testing and length of delay– In general, more accurate when choice test, but not significant

• Exp 4:– Had pigeons rate their confidence level for “answers”– Trained on conditional discrimination (DMTS)– Again, choice vs. forced and the delay interval examined– Results:

• None of pigeons chose to gamble after incorrect response• Ambiguous choice for gambling after correct responses• Accuracy dropped with longer delay intervals, but no affect on

confidence

Summary of pigeons and metamemory

• Bottom line: little evidence for metamemory in pigeons, even with high accuracy for DMTS task!

• Can perform the task, BUT appear to be “unaware” of how strong or accurate their memory might be

• Unlike other higher mammals and some birds – Interesting because of strong performance – But absence of metamemory

Sea Lions• 2 female Sea lions: Rocky and Rio

• Procedure:– All initial stimulus training = problems with 2 stimuli– Novel stimuli always paired with novel stimuli

• Large number of stimuli used– Allowed assessment of novelty effects– Each comparison stimuli had an equal probability of appearing as S+ and

S-: maintains conditionality (A=B or B=A)

• Hypothesis: Identity matching experience that is gained by completing one test will facilitate performance on subsequent tests.

Experiment 1• At beginning of trial: sample stimulus exposed for 4 sec,

then 2 side doors opened revealing 2 choices (S+ and S-)– Simultaneous conditioning– Nose poke was operant response; Sr = fish

• Training:– Exclusion phase: correct vs. familiar, familiar = S-– Trial and error: all novel stimuli, trained until 90% correct– Reshuffling: any stimulus could appear with any other within

the concept

• Why reshuffling?– Additional experience– Dependence on context eliminated– Minimize control by other unintentional stimuli

• Testing: 30 novel stimuli in 15 paired problems– 4 training sessions– Then test stimuli

• Assessment:– First trial performances compared with chance (50%)– Test trials into 2 groups:

• Trials 1-4 (trial 1 alone, too)• Trials 5-8 • Compared these 2 groups compared to baseline

– Examined 4 test groupings as a test to be passed or failed: 3/4

Results of Sea Lion MTS

• Training:– Rio learned first problem more easily (90% or higher)– But: Initial probe trials with novel stimuli , she scored

only at chance (50%).

• Reshuffling:– No decrement in performance for either sea lion– Showed transfer of training between stimuli– Appeared to be responding according to identity

relationship

Reshuffling: Test 1:– Rio:

• first set NOT better than chance• But further training: 90% or better• Treated novel problems differently than familiar• Interestingly, vocalized and touched novel stimuli more• Novel stimuli appeared to disrupt Rio’s behavior

– Rocky:• No apparent reaction to novelty of stimuli• Test 1 was ambiguous• Test 2 was improved• But: overall, performed well on both tests• In general: performed as well as during baseline

– Pass/fail analysis:• Rio passed all• Rocky passed 14/15 then 15/15

Experiment 2

• Assess degree to which generalization of matching rule would occur with stimluli previously encountered in nonidentity context.– Retrained sea lions on arbitrary MTS task that they

previously had extensive training on (changed the pairings)

– Tested on MTS using familiar stimuli from old task• Same procedure, but different pairing of stimuli• Test with familiar, not novel stimuli

Results of Experiment 2 with Sea Lions

• Pass/Fail analysis:– Rocky: 10/10 for first set; 8/10 for second set– Rio: 7/10 and 8/10– Not as many 100% as in novel training– Did show reflexivity among elements previously

related only to dissimilar or nonmatching stimuli

• Suggests that there was some interference from previous training

Conclusions regarding Sea Lions• Sea lions were able to transfer identity concept to novel problems in visual MTS test

• Why successful?– Large number of exemplars– Extended training– Reshuffling phase allowed problems to be broken up, reducing reliance on unintentional

attributes….This way, selecting only for the identity relation– Habituated to novelty

• Individual differences apparent:– Experience– “intelligence”

• How transferable is MTS? May depend on “abstractiveness” of concept– Context important: what can the abstract concept be grounded with?– MTS not necessarily limited by precise context that is learned

DTMS and human children

• 12 children in 3 groups (MA 14-36 mos)– Normally developing preschoolers– Mentally retarded with near typical language– Mentally retarded with no language development

• Stimuli:– 4 conditional discriminations:

• If A then B• If D then E• If A then C• If D then F• Matching made up animal like figures using MTS

DTMS and human children• Training: Presented A or D as sample, B,E or C,F as comparisons

– 3 stimuli presented on paper– Sample at top, two choices at bottom

• Test: equivalence indicated by matching B and C or E and F– B or E as sample with C and F as comparisons– C and F as sample with E and B as comparisons

• Each child taught and tested individually• Reward = short activity or treat• Did use visual prompting• Obtained interobserver agreement and reliability estimates

Language and kids: Results• Looked at group and individual data• Data graphed as percentages of unprompted

correct responses in blocks of 10 consecutive trials

• Performance varied across 3 groups:– Typical and retarded/language required fewer trials to

mastery– About 100 for typical; 225 for retarded/language; 500

for retarded/no language

Language and kids: Results• Equivalence test:

– Individual data– Did track # of no responses made by child during each block of 10 trials: did not

differ x group– % of correct responding = # correct responses/total number of responses in block

• Normal group: 84.5% correct• Retarded/language: 78.25%• Retarded/no language: 44.5%- very close to chance

• Typical and retarded/language children improved across the equivalence testing phase:

• Normal: 77.5 to 95.5• Retarded/language: 69.75 to 88%• Retarded no language: 46.25 and 39.25%

Language and kids: Results

• Data suggest that language/symbol use may be necessary for development of stimulus equivalence in young children– Not that couldn’t learn discriminations– Couldn’t learn conditional discriminations under these conditions

• Literature shows can learn with overtraining

• Seems to be lack of symmetrical responding rather than inability to show transitivity

• Slower to learn overall• May just take longer

Conclusions• Which comes first: equivalence class learning or symbol use?

– Animal data suggest equivalence class• Pigeon data: could do task, but not aware• Sea lion data: better transitivity and symbol use

– Higher mammals, primates, dogs show transitivity and symbol use

• Is language learned, innate? – Is it a process that requires multiple inputs from genetics,

environment – Synergistic interactions between nature and nurture?

• But is it required to discriminate complex stimuli?– Answer seems to be, depends on the type of complex stimuli!