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Chapter 12.docx

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Anneke Olthof

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Chapter 12 – Food Caching & Recovery Chapter preview: - Research on the remarkable ability of some bird species to retrieve food that they previously stored in various locations. - Studies of food caching are a major source of information about spatial memory and episodic memory in nonhuman species - We look at how behaviour is organized in time, a ubiquitous feature of the environment, and how organisms learn about the serial order of stimuli, which is a pre-requisite for numerical skill. - We also talk about research on tool use, with emphasis on recent research on tool use in New Caledonian crows - Most complex cognitive behaviour = language (collection of cognitive skills – evident in a number of nonhuman species) Food Caching and recovery Clark‟s nutcracker - Stores 33,000 seeds in caches of 4- These birds live in alpine areas of 5 seeds each and recovers several the US and harvest seeds from pine thousand of these months later cones in late summer and early autumn. They hide the seeds in underground caches and recover them months later in the winter and spring when other food sources are scarce. Black-capped - Stores hundreds of individual seeds Pravosudov and Clayton(2002) chickadee and recovers them a month later - Compared food caching and recovery in two populations of black-capped chickadees (those living in Colorado and those living in Alaska). Although both environments have harsh winters, the weather in Alaska is more challenging. - Alaska chickadees were better on a non-caching spatial memory task and stores more foods and were more efficient. Need to consider: I. What food items to - Perishable (should be recovered cache quickly) vs. Non-Perishable (don‟t have to be recovered quickly) II. Where to store - Somewhere it can be recalled food III. Social component - Can‟t allow competitor to find food - Do not want to store food where a competitor is watching you bc then competitor would take your food IV. Where to look for - Whether to look in the presence of stored food during a competitor, which foods to recovery retrieve first, and whether to eat or re-store what you recovered Spatial memory in food - Spatial memory being used, or Kamil & Balda (1985) caching and recovery other strategies - Tested nutcrackers in room with - Search randomly (kinda like 180 recessed cups of sand on an easter hunt – problem floor, along with many with that strategy: it can turn landmarks that the birds could into a life-and-death use situation) - Given a choice of 18 cups to - have favourite hiding spots store seeds for food (keep reusing a - Birds would readily cache food subset of 50 spots, items minimizes load on memory) - Tested 10 days after storing - mark cache sites (with a with all 180 cups available drop of urine - Where does the bird go to get - smell or see stored food the food? Will it remember (they can just see the food where they ate the food 10 days itself) ago ? - Results: went to cups where stored food significantly greater than chance. - Indicates that cache recovery reflects spatial memory - Evidence of spatial memory!! - Could not have been using: Favoured cache sites o Experimenter gave subset of cache locations to choose to hide seeds in (by only making 180 available) - Not identified by disturbed sand o Experimenter smoothed sand in all cups (before the birds went into to search, the experimenter made sure everything was smoothed over) - Not identified by smell o Searched at same locations even if seeds gone - Suggests performance reflects spatial memory Balda & Kamil found that memory of nutcrackers for the spatial location of cached food lasts as long as 286 days (longest retention interval tested) Episodic memory in Clayton & Dickinson (1999): food caching & - In lab, let scrub jays (food- recovery: storing bird) cache peanuts and mealworms in an ice cube tray - Episodic - Involves information about what, and then recover them later memory: where & when an event - Control Group: P & W good at happened both intervals – both the peanuts - Specific event or episode and worms were good (not - „walking across the stage during spoiled) at the 4 hr and 124 hr graduation, attending a wedding interval. of a good friend‟ - Spoiled Group: P & W good at - Can be rich in detail 4 hours, but only P good at 124 - Controversial whether episodic hrs. (bc researchers took them memory is uniquely human and soaked them in nasty dish - It was once declared by tolvin(or liquid) something) that animals do not - Where do they search? have episodic memory. - For test trials, the food items - Then everyone started to try to were removed so they couldn‟t find episodic memory in animals see or smell the worms and - The phenomelogical component peanuts – bargraph on slide [the of episodic memory is that you are light bar is worms] aware that it was in the past and - Looked at where searched on you are remembering it. test trials with all food removed - Clayton,Bussey & Dickinson - Found birds avoided spoiled argue that episodic memory in worms at long intervals - To do this, birds must have non-human species has to have certain content (the memory has remembered what they cached to include info about what where they cached it, and when happened, when it happened, and they cached it. where it happened) - It has the three components that - The what, where, when info is we stated what an episodic integrated into a representation of memory is! the past episodes which has to be - Suggests episodic-like memory available for flexible use in in scrub jays dealing with new problems ! Categorization & Concept Learning Perceptual concept learning - Similar procedures have found Herrnstein et al. (1976): that pigeons can discriminate - Reinforced pecks to between pictures containing: pictures containing trees - People vs non-people (S+) and didn‟t reinforce pecks to pictures without - Animals vs non-animals - Kingfishers vs other trees (S-) birds - Learned to peck more to - Letters of the alphabet tree pictures than non-tree - Monet vs Picasso - Generalized to new tree pictures - Trained with like 17,000 - Side note: Pigeon has 5 pictures and all pics were colour receptors (they kick different (they were our butt when it comes to presented from all diff vision) seasons, different colours, palm trees, different trees!) - They pecked more to tree pictures than non-tree pictures - They could still peck on a new tree picture ! - Polymorphous category: it would be really hard to come up with a list of significant characteristics- there are no requirements to be a tree! (pigeon could not pick one feature of a tree bc trees are so different) Bhatt et al. (1988)” Pigeons can discriminate - The “name game” between 4 categories at the same - 10 pictures from each of 4 time categories    - Each category corresponded to 1 of 4 keys - Found birds easily learned this task - Performed equally well with natural human-made items - If you show a pigeon of ¼ category they can match it to the correct key! - Generalized to new images - The ones they were trained with, they were successful but with new images they were above change (meaning they were successful too!) Bhatt et al. (1988) - Examined the effects of number of training exemplars and found pigeons - Learned categories fewer and more accurately with fewer training exemplars - Showed better transfer with more training exemplars - If you are training the pigeon with a small stimulus set, then they don‟t generalize to new images and have a hard time distinguishing the new images How do pigeons form Vaughan & Green (1984) categories? - found pigeons could discriminate 320 pictures of squiggles, and still remember them 490 days i. Memorization later! Cook et al. (2005) - found pigeons can remember over 800 pictures - Successful transfer tests to They have the memory ii. Not novel stimuli (since they can capacity to do this ! memorization transfer to novel stimuli – it Not sure if this is cannot be memorization then) memorization - Pseudocategory evidence: easier to learn category if assign 10 pictures from same category to each of 4 keys than if assign 10 random pictures from all different categories to each of 4 keys - Between group differences are important: easier to discriminate an oak leaf from non-oak leaves than a particular oak leaf from other oak leaves. (between group differences are important – proves that we do not rely on memorization!!) Feature Theory: - Argues that a concept has a - Cerella(1980) trained set of defining features pigeons to discriminate - If the defining features are Charlie Brown from other present in the picture, then Peanuts characters reinforcement is available. When tested with scrambled - Consistent with Rescorla- versus intact Charlie found no Wagner model; difference. Cerella trained After learning, several pigeons to distinguish Charlie features would have brown to other peanut inhibitory strength, others characters. And that pigeons excitatory and others may were equally successful to have no associative strength determine Charlie brown - Would allow generalization through intact or scrambled. to novel stimuli (doesn‟t matter the configuration) BUT Waserman et al(1993) found scrambled pictures test performance much worse than intact pictures. What set of defining features make up a polymorphous category (trees,animals)? - It may bias you bc the characters are the same. - Cerellla & Waserman are contradicting each other. - Waserman won this one ! Evidence against the feature theory! Prototype Theory: - Argues that the category Jitsumori (1996) found representation is an average pigeons responded most to of all the exemplars novel test stimulus that experienced represented the average of all stimulus features used in - As you go out in the world training (he always withheld and see cats. All the cats that the average one but then when you‟ve encountered, you‟ve he tested, the pigeons constructed a prototype and responded to the average one! once you encounter a new – supports prototype theory: cat, you compare the new cat even though they did not have with your prototype that training with this stimulus, but you‟ve created in your mind. when they were shown the stimulus! They could distinguish it. BUT Pearce (1989) found pigeons responded most to novel test stimulus that represented an extreme of all stimulus features used in training. Learning of prototype can be explained by feature theory. - It is possible that the more predictive features of a category can become the prototype that you can use to compare new instances with! Exemplar Theory: - Argues that every exemplar - So every cat that you‟ve experienced is stored in seen is stored in your memory and new exemplars memory are judged as member of the - Each cat in your memory category to the extent that has its own stimulus they are similar to the generalization. exemplars in memory - Creating a specific stimulus - Spencian model: each generalization for each cat! exemplar in memory has - Better generalization to its own generalization new exemplars when you gradient are being trained with new BUT exemplars! - Is this really a concept? Serial List Learning Serial List Learning - Learning about the order of Tests with subsets: arbitrary stimuli (i.e: A-B-C- - Evidence pigeons and D) monkeys solve this - Imagine being presented with task differently Pigeons: Terrace (1987) all the alphabets and then you have to respond to them in - Poor performance on order. interior pairs suggests - Can animals learn about the learning simple rules order? - No line of reason, they just Monkeys: D‟Amato & follow a certain order. Columbo (1988) - Performed accurately on interior pairs Possible strategies: - Latency data suggests mentally walking
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