Download Can Animals think?

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 problemsolving 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
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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:
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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”
• 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
• 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”:
• 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:
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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
Sea Lions and DMTS
• 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
Experiment 1
• Testing: 30 novel stimuli in 15 paired problems
• 4 training sessions
• Then test novel stimuli
• Assessment:
• Order effect: initial trial performances were about as accurate as chance (50%)
• Divided Test trials into 2 groups: Compared these 2 groups compared to baseline
• Trials 1-4 (trial 1 alone, too)
• Trials 5-8
• Examined test groupings as pass or fail: pass = ¾ items correct
Results of Sea Lion MTS
• Training:
• Rio learned first problem more easily (90% or higher)
• But: On initial probe trials with novel stimuli , she scored only at chance (50%).
• With more trials her accuracy increased
• 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:
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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:
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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 the degree to which generalization of a matching rule would
occur with stimuli previously encountered in nonidentity context.
• Retrained sea lions on arbitrary MTS task with stimuli that they
previously had extensive training on (changed the pairings, stimuli
were the same as first tests)
• Tested on MTS using familiar stimuli from old task
• Same procedure, but different pairing of stimuli
• What was the difference: Test with familiar, not novel stimuli
Results of Experiment 2 with Sea Lions
• Pass/Fail analysis:
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Rocky: 10/10 for first set; 8/10 for second set
Rio: 7/10 and 8/10
Overall did not obtain as many 100% test 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 were apparent:
• Experience
• “intelligence” (are there smart and dumb sea lions?)
• 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
• Cognitively impaired with near typical language
• Cognitively impaired with no language development
• Stimuli:
• 4 conditional discriminations:
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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
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”!
Spatial Memory
• Spatial memory = memory for places
• Why might this be important for animals?
• How can we test spatial memory in the laboratory?
• Morris Water Maze:
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Typically used with rats or mice
Large water tank
Spatial cues placed around the room (decals on walls, location of doors, windows, etc.)
Placement of platforms (start and finish) are tied to different “landmarks”
Data show that rats and mice do indeed use the landmarks
• https://www.youtube.com/watch?v=LrCzSIbvSN4
Spatial Memory
• Radial Arm Maze
• A maze with many arms: typically use 8 in labs
• Food hidden at end of the arms
• Examine search strategies
• https://www.youtube.com/watch?v=LU36985DlMk
Spatial Memory
• Can examine prospective and retrospective memory
• Prospective = imagining the future
• Retrospective = remembering the past
• Using radial arm maze: do rats look forward or backward?
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Do they remember where they have been or where they have yet to be?
For first few arms: retrospective
After 4-5 arms: prospective
In a sense, they use whatever is less to remember!
• Why might spatial memory be more important for animals such as rats than concept
formation?
Vaughan and Greene (1973):
Classification of pictures by Pigeons
Pigeons trained to classify slides as positive or negative
• Random assignment to + or _ category: No concept involved
• After 10 sessions, could classify 80 slides (40 + and 40-)
• Learned the next 80 even faster
• Eventually worked up to a total of 320 slides
• Results showed that pigeons could easily learn this classification even
with no concept involved.
Herrnstein, 1976:
Concept formation in Pigeons
• Wanted to see if pigeons could learn to categorize complex stimuli
• Three categories:
• Trees
• Water
• Person
• Found that pictures being seen for first time (novel) discriminated as well as
training pictures
• Interestingly- similar patter of errors and correct discrimination across the
pigeon subjects
What does this mean?
• Ability to discriminate open-ended classes of stimuli poses problems
at two levels:
• Analysis of features
• Analysis of properties
• Analysis of features: Enabling subject to tell whether object is
member of particular class
• Analysis of properties: Enabling subject to tell whether stimuli are of
similar or different classes such that it renders the stimuli
discriminable
To what were Herrnstein’s Pigeons responding ?
• Slides had complex composition: Too complex to be categorized alon
simple common elements
• Rather: the slides contained a cluster of features that were more or
less isomorphic-probabilistic conjunctions and disjunctions
• Look like semantic categories of generalization:
• We classify the slides on the basis of a semantic category
• But: are semantic labels necessary?
• Did the pigeons label the categories (trees, water, people)
• Or did the pigeons just categories on the basis of the features?
Does evolution play a role:
• Are pigeons prewired to see trees, water, people?
• Presence of static features can be discriminated
• If they are, do they have to give the trees, water or people a language
label or can the pigeons categorize without language/semantic labels?
• More likely that pigeons are prewired to form a “schema” or prototype
• Examine behavior of other species to determine how behavior
may be “prewired” and learned
• Language is not necessary to form “concepts” or categories
• Language may make concept labeling and categorization more efficient
Metamemory
Memory without Awareness?
Pigeons can remember, but are they aware how well they remember?
• Metamemory
• Awareness of how your memory works and an awareness of how much/how well you can remember
• 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, besides humans, has shown metamemory
• Monkeys and nonhuman primates
• Dogs
• Some evidence in rats and pigeons
Metamemory Pigeon Experiments
• Pigeons show vast memory ability and strong discrimination abilities
• Very good at MTS and DMTS; Can classify very complex stimuli
• But are they AWARE of how well they remember?
• Experiment 1: Ask birds chose between fixed small # of pellets and varying probabilities of
larger # of pellets
• Fixed choice= Escape: NO test, just get the smaller reward
• Variable = larger reward for remembered or none for miss ; size of reinforce varies and pigeon has to
remember
• Over time all birds chose constant reinforcer and switched away from higher variable
payoff
• No differences in memory, Just a difference in preference
• Suggests pigeons weren’t willing to “risk” their payoff
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 if pigeons had less memory  chose easy discrimination choice
when had choice
• Results:
• No memory effects: 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
• Experiment 3:
• Now present choice to escape simultaneously with no escape choice
• Again examined forced vs. choice testing and length of delay
• In general, more accurate when choice test, but memory accuracy not significantly
different from forced test
• Experiment 4:
• Had pigeons rate their confidence level for “answers”
• Trained on conditional discrimination (DMTS)
• Again, choice vs. forced and varied the delay interval between presentation and test
• Results:
• None of pigeons chose to gamble after an 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 memory performance
• But absence of metamemory: Do not seem to be aware of how well
they remember!
So what does this all mean?
• Memory is not necessarily tied to language
• Language or symbol use is tied to higher level cognitive tasks, but is not necessary
• Animals such as pigeons can learn to classify complex stimuli
• Are surprisingly accurate
• Show similar patterns of forgetting (as more to remember, more difficult to remember)
• But: Animals such as pigeons do not seem to have an awareness of their memories or how their
memory works.
• Animals with greater symbolic memory seem to have greater metamemory and awareness of how their
memory works.