Lecture 23: Animal Cognition II (Special Topics) Learning, Psychology 5310 Spring, 2015 Professor Delamater

Selected Special Topics in the Study of Comparative Cognition 1.Episodic memory in non-human animals 2.Interval Timing 3.Serial Order learning 4.Categorization and Concept Learning

Episodic Memory: Food Caching Birds 1.Kamil and Balda (1985) study 2.Clayton and Dickinson (1999) study Clark’s nutcrackers live in Alpine regions of the western US. They are known for their uncanny ability to retrieve cached food in the wild. They store seeds from pine cones during the summer and fall, and then retrieve them in the winter and spring. They can store up to 33,000 seeds and recover several thousand of them at some later time. Can they do this because they remember well, or because they can spot markings of where they’ve been? Or just randomly run into food they’ve or others have previously stored? Kamil and Balda (1985) study

Episodic Memory: Food Caching Birds 1.Kamil and Balda (1985) study 2.Clayton and Dickinson (1999) study Kamil and Balda forced the birds to store up to 18 seeds in a laboratory environment with 225 storage holes. However, only 18 were available at any given time. Then, after some delay period, they were allowed to retrieve their stored caches. But, during this retrieval test, all 225 storage holes were accessible. The birds could recover their caches 2-4 times greater than would be expected by chance. Furthermore, they could remember these after as long as a 285 day delay.

Episodic Memory: Food Caching Birds 1.Kamil and Balda (1985) study – This study shows an amazing memory ability. 2.Clayton and Dickinson (1999) study – This study shows some evidence for episodic memory in birds (Scrub Jays). What is “episodic” memory? Is it uniquely human? a. Usual answer is that it is a recollection of a particular event that took place in a particular location at a particular time. In essence, you reexperience the episode. b. Aside from the conscious aspects of this memory, it can be characterized As a memory containing “what,” “where,” and “when” information. c. Clayton and Dickinson (1999) asked if scrub jays had this kind of memory.

Episodic Memory: Food Caching Birds Clayton and Dickinson (1999) study Birds were asked to cache different types of food (peanuts and mealworms) into ice cube trays that had sand in them and were surrounded by lego block structures. Then they were asked to retrieve them after 4 or 124 hour delays. Some birds learned, though, that the meal worms deteriorated after 124 hours, whereas for others the bad mealworms were replenished with fresh ones.

Episodic Memory: Food Caching Birds Clayton and Dickinson (1999) study Since the jays preferred mealworms to peanuts, the Replenish group always retrieved more mealworms (W) than peanuts (P) during the 4 and 124 hour tests. The birds that learned that mealworms decay after 124 hours preferred the peanuts to the mealworms after 124 hours, but worms to peanuts after 4 hours. This means that the birds knew after 124 hours what food was stored where and when it was stored there. This suggests that the scrub jays, like humans, may have episodic memories.

Interval Timing: Methods & Properties 1.Duration Estimation (symbolic matching to sample task….) In the duration estimation task, the subject judges whether the first stimulus (the sample stimulus) is short or long. If it is short, then choosing the left response is reinforced with food, but if it is long, then choosing the right response is reinforced with food. Tone Choose Response 1 if short Choose Response 2 if long Sample Stimulus Choice

Interval Timing: Methods & Properties 1.Duration Estimation (symbolic matching to sample task….) 2.Peak Procedure (duration production) In the peak procedure, a stimulus comes on and signals reward opportunity after a fixed interval (e.g., FI 20 s). But on nonreinforced probe trials, the duration of the trial is extended and no reward can be earned. It is on these trials that we assess responding as a function of time. Response S Training trials Fixed Interval 20 s S Nonreinforced Probe trials 80-s S duration Reward Response

Interval Timing: Methods & Properties 1.Duration Estimation (symbolic matching to sample task….) 2.Peak Procedure (duration production) In this case one discriminative stimulus signaled FI 20 reward, while a second signaled FI 40. The rats lever press rate on probe trials peaked at 20 and 40 s, respectively, in the presence of the two stimuli. This indicates that they have learned about reward time. Also, not that the variability (spread) of the two timing functions differ. The amount of variation increases with the mean of the interval being estimated. Roberts (1981) study In fact, responding is related to the proportion of time elapsed, independent of the value of the interval being judged. This is known as the scalar invariance property of interval timing.

Interval Timing: Theories 1.Scalar Expectancy Theory (Gibbon & Church, 1984) 2.Behavioral Theory of Time (Killeen & Fetterman, 1993) 3.Multiple Oscillator Theory (Church & Broadbent, 1990) There are clock, memory, and decision processes in the scalar expectancy model. Clock generates counts in an accumulator. Memory: Running count vs reinforced memory count (at time of reward). Decision: Compares running value of elapsed time in working memory to the stored reinforced time in reference memory. Comparator rule shows how behavior will be proportionally related to the value of the reinforced time in reference memory. Gibbon and Church, 1984 Comparator: (N* - N) < b (threshold) N*

Interval Timing: Theories 1.Scalar Expectancy Theory (Gibbon & Church, 1984) 2.Behavioral Theory of Time (Killeen & Fetterman, 1993) 3.Multiple Oscillator Theory (Church & Broadbent, 1990) In the Multiple Oscillator theory, there are different oscillators that run concurrently. Each oscillator has a different periodicity. Each moment in time has a different pattern of activation across the different oscillators. These different patterns of activation are thought to code different temporal intervals. Church and Broadbent, 1990 Time 1 Time 2

Serial Order Learning 1.Learn a sequence of responses: (Fountain, et al, 2012) 2.Do the rats learn an internal representation of the sequence or do they learn a chain of S-R associations? They learn a structured sequence better than a non-structured one. But that could be understood in terms of easier associative learning….

Serial Order Learning 1.Learn a sequence of responses: (Fountain, et al, 2012) 2.Do the rats learn an internal representation of the sequence or do they learn a chain of S-R associations? 3. Terrace, Son, and Brannon (2003) study Monkeys first learned 4, 7-item sequences: A1 – A2 – A3 – A4 – A5 – A6 – A7 B1 – B2 – B3 – B4 – B5 – B6 – B7 C1 – C2 – C3 – C4 – C5 – C6 – C7 D1 – D2 – D3 – D4 – D5 – D6 – D7 These stimuli were different pictures taken from several different categories. Then the monkeys were given a set of 2-item probe tests consisting of different stimuli from the different sets. They asked whether the monkeys could accurately select the first item. A3 – C5, B2 – D4, C5 – D7, D3 – A4, etc The monkeys DID choose the “earlier” item of each sequence even though these particular items were never trained together. It looks like the monkeys had constructed a representation of the order of each sequence, and this order guided their choices, not a series of S-R associations.

Categorization & Concept Learning 1.Classic Herrnstein, Loveland, and Cable (1976) study Pigeons learn to categorize pictures of people vs plants. A control group is trained to arbitrarily categorize different sets of stimuli. The individual stimuli chosen for this study are taken from a large number of items (somewhere on the order of 100 or more). Then, during a test phase the animals are tested with NEW exemplars (ones they never saw before), and were asked to choose to respond. The birds learning the Categorization task did so fairly well, with some loss in accuracy. Later work has shown that greater generalization occurs in these tests as the number of exemplars in the training set increases.

Categorization & Concept Learning 1.Grainger, et al (2012) study with baboons Baboons first learned to categorize English words vs non-words (up to over 300 exemplars of each) Then they were tested with new words and non- words they hadnt seen before. They’re performance was pretty good, as can be seen on the graph to the right.

Categorization & Concept Learning: Mechanisms of Concept Learning 1.Aust and Huber (2003) study with pigeons The birds first learned to classify pictures of people vs no people Then they were tested with new exemplars of people that were in their original form or were rearranged in various ways. The birds responded most when the new people were in their original form, but they responded more to rearranged people than to slides with no people in them. This suggests that the birds responded at least partly on the basis of the specific features making up the original slides. This is the Feature Theory of Concept learning. Notice how this is rather similar to the Rescorla-Wagner theory of simple conditioning.

Categorization & Concept Learning: Mechanisms of Concept Learning 2. Wright and Katz (2007) study with pigeons, rhesus monkeys, capuchin monkeys This was a Same/Different concept learning task Do these species learn “abstract” concepts? If the two objects on a trial are the same, then touching the lower picture is correct. If the two objects are different, then touching the button to the right of the lower picture is correct. After the basic learning phase, then the animals are given tests with new exemplars. The basic findings are that generalization to new exemplars increases as the number of training exemplars increases. This result occurs in all species suggesting that all species may learn in similar ways. Perhaps they are abstracting some general notion of sameness, and responding on the basis of this representation. Further work is needed to clarify the nature of that representation.