A behaviorist perspective on comparative cognition Can Animals think? A behaviorist perspective on comparative cognition

Comparative Cognition Evolutionary approach: cognitive mechanisms evolve in response to selective pressures peculiar to each species’ ecology, physiology and morphology Thus cognitive processes differ across species Comparative cognition: compare abilities across species Analyze performance of different species on same set of tasks Focus on species-specific mechanisms and strategies that underlie problem- solving performance Better to understand how different animals problem solve rather than Try to determine which animal is “smarter” Must use a set of tasks, not a single task

What behaviors to study? Relearning Altering habits and adapting to change by switching to different solution routine Behavioral flexibility Neophilia Exploration strategies Attention Motivation Affordance learning Physiological constraints

Cognitive Ethology! Cognitive ethology assumes that animals are capable of conscious thought and intentionality Normally traits given just to humans Assumption is data driven: Animal behavior shows complexity, flexibility and cleverness Conscious intent is demonstrated by these behaviors

Experimental Psychology Experimental psychologists use comparative cognition in more limited way “objective evidence cannot give a demonstration either of the existence or the nonexistence of consciousness, thus consciousness is precisely that which cannot be perceived objectively.” Comparative cognition = theoretical constructs and models used to explain aspects of behavior that cannot be readily characterized in terms of simple S-R mechanisms

What is the problem? When causal inferences about “rich mental life” of an animal is made, one may be projecting own thoughts/emotions/intentions on that animal Anthropomorphism = projecting human qualities onto animals Remember that cognitive mechanisms involving internal representations are theoretical constructs inferred from the behavior of organisms This is true for both humans AND animals! We must be careful when making causal inferences and tying them to internal states when all we have is behavior as our data

Morgan’s Canon: Accept the lowest level of intentional explanation that works Natural selection: what matters is that the animal achieves goals such as finding food, mates, and safety. Using Morgan’s canon to choose among alternatives assumes that natural selection has always produced the lowest level intentional system that can do the job. But doesn’t answer the question of how the animal does this!

Why is this relevant? Functional concerns of behavioral ecology and ethology often lead to mechanistic questions -- which are the realm of cognition. Cognitive ethologists are frequently concerned with the diversity of solutions that living organisms have found for common problems. Emphasize broad taxonomic comparisons Do not focus on a few select representatives of limited taxa (we hope). Looking for general principles of behavior or cognition.

Behavioral ecology can inform questions of cognition Optimal Foraging Theory: maximize rate of energy intake and fitness. Example: Woodpecker takes longer on some trees than on others when foraging. Assume: adaptive, optimal, maximizing energy, maximizing fitness. Function: avoid depleted food, avoid predation, stay close to nest. Mechanism: how know depleted, what info tells bird to change behavior, how does it know where its nest is? Measure: distances between trees, prey repletion rates, prey energy, etc.

What about memory? Do animals show evidence of “memory” If so, do they show different KINDS of memory How are different animals’ memory similar or different: Across species In comparison to human memory How is an animal’s memory altered? What factors impact the formation of memory? What kinds of things are remembered?, How can animal memory be explained in terms of function?

Compare to Human memory: Kinds of Memory Reference: Information that is procedural and long term. How to dial phone Working: event specific and short term. What number to dial.

Matching to Sample and Language Is metacognition or metalinguistic awareness necessary?

Equivalence Class Three defining relations for determining equivalence: 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 defined: Symbol and referents form functionally substitutable elements Relation between symbol and referent not unidirectional (reflexivity and symmetry) 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 and Corvids Dogs Pigeons to lesser degree Sea animals: Seals, sea lions, orcas, dolphinsw What cognitive abilities are necessary for this?

How test “concept formation” 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 Do animals remember differently when directed to forget? Use MTS task again Now add a delay: DMTS

Procedure for Testing Pigeons: 6 pigeons in a 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 OR 2 sec with no stimuli presented Used different delays: 6-15 seconds After the delay: 2 keys light up: Red and Green Peck to Red reinforced if trial begun with NO food but a stimulus Peck to 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”: Group “dark”: 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 Forgetting-cue and 40 Remember cue probe trials

Results for early trials with the 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 Forgetting-cue probe trials relative to Remember-cue trials for both Part A and Part B training Remembered less when cued to forget! Remember-cue trials were more accurate than Forget-cue, particularly when Forget-cue was house light and not darkness

Experiment 2 Examined effects of cuing and the predicted time course of cueing Also examine feature positive vs. feature negative effect Method: 6 birds again Trained on basic task with no delay Trained to flashing vs. steady house light Trained to dark vs. light Added probe trials

Results of Experiment 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! (remember feature positive effect….how does this tie in?)

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 Is this similar or different to humans? Suggests must engage in mediating behaviors to maintain remembering

DTMS and human children 12 children in 3 groups (MA 14-36 mos) Normally developing preschoolers Cognitively impaired with near typical language Cognitively impaired 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 children with cognitive impairments (CI) but with language: required fewer trials to mastery About 100 for typical; 225 for CI/language; 500 for CI/no language

Language and kids: Results Equivalence test: looked at 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 Results showed differences by cognitive ability AND language ability: Normal group: 84.5% correct CI/language: 78.25% CI/no language: 44.5%- very close to chance Typical and CI/language children improved across the equivalence testing phase: Normal: 77.5 to 95.5 CI/language: 69.75 to 88% CI/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

Animals can categorize in amazing ways! http://www.pbs.org/wgbh/nova/nature/how-smart-are-animals.html

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 or innate? Is it a process that requires multiple inputs from genetics, environment Synergistic interactions between nature and nurture? Can’t have language with equivalence class But is LANGUAGE required to discriminate complex stimuli? Answer seems to be, “depends on the type of complex stimuli”!