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Shettleworth, S. J. (1985). Handling time and choice in pigeons. J Exp Anal Behav, 44(2), 139–155.
Abstract: According to optimal foraging theory, animals should prefer food items with the highest ratios of energy intake to handling time. When single items have negligible handling times, one large item should be preferred to a collection of small ones of equivalent total weight. However, when pigeons were offered such a choice on equal concurrent variable-interval schedules in a shuttlebox, they preferred the side offering many small items per reinforcement to that offering one or a few relatively large items. This preference was still evident on concurrent fixed-cumulative-duration schedules in which choosing the alternative with longer handling time substantially lowered the rate of food intake.
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Reid, P. J., & Shettleworth, S. J. (1992). Detection of cryptic prey: search image or search rate? J Exp Psychol Anim Behav Process, 18(3), 273–286.
Abstract: Animals' improvement in capturing cryptic prey with experience has long been attributed to a perceptual mechanism, the specific search image. Detection could also be improved by adjusting rate of search. In a series of studies using both naturalistic and operant search tasks, pigeons searched for wheat, dyed to produce 1 conspicuous and 2 equally cryptic prey types. Contrary to the predictions of the search-rate hypothesis, pigeons given a choice between the 2 cryptic types took the type experienced most recently. However, experience with 1 cryptic type improved accuracy on the other cryptic type, a result inconsistent with a search image specific to 1 prey type. Search image may better be thought of as priming of attention to those features of the prey type that best distinguish the prey from the background.
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Krebs, J. R., Clayton, N. S., Hampton, R. R., & Shettleworth, S. J. (1995). Effects of photoperiod on food-storing and the hippocampus in birds. Neuroreport, 6(12), 1701–1704.
Abstract: Birds that store food have a relatively large hippocampus compared to non-storing species. The hippocampus shows seasonal differences in neurogenesis and volume in black-capped chikadees (Parus atricapillus) taken from the wild at different times of year. We compared hippocampal volumes in black-capped chickadees captured at the same time but differing in food-storing behaviour because of manipulations of photoperiod in the laboratory. Differences in food-storing behaviour were not accompanied by differences in the volume of the hippocampus. Hippocampal volumes also did not differ between two groups of a non-food-storing control species, house sparrows (Passer domesticus), exposed to the same conditions as the chickadees.
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Shettleworth, S. J. (2001). Animal cognition and animal behaviour. Anim. Behav., 61(2), 277–286.
Abstract: Cognitive processes such as perception, learning, memory and decision making play an important role in mate choice, foraging and many other behaviours. In this review, I summarize a few key ideas about animal cognition developed in a recent book (Shettleworth 1998, Cognition, Evolution and Behaviour) and briefly review some areas in which interdisciplinary research on animal cognition is currently proving especially productive. Cognition, broadly defined, includes all ways in which animals take in information through the senses, process, retain and decide to act on it. Studying animal cognition does not entail any particular position on whether or to what degree animals are conscious. Neither does it entail rejecting behaviourism in that one of the greatest challenges in studing animal cognition is to formulate clear behavioural criteria for inferring specific mental processes. Tests of whether or not apparently goal-directed behaviour is controlled by a representation of its goal, episodic-like memory in birds, and deceptive behaviour in monkeys provide examples. Functional modelling has been integrated with analyses of cognitive mechanisms in a number of areas, including studies of communication, models of how predator learning and attention affect the evolution of conspicuous and cryptic prey, tests of the relationship betweeen ecological demands on spatial cognition and brain evolution, and in research on social learning. Rather than a `new field' of cognitive ecology, such interdisciplinary research on animal cognition exemplifies a revival of interest in proximate mechanisms of behaviour.
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Shettleworth, S. J. (1998). Cognition, Evolution and Behaviour. Oxford: Oxford University Press.
Abstract: Description
How do animals perceive the world, learn, remember, search for food or mates, and find their way around? Do any non-human animals count, imitate one another, use a language, or think as we do? What use is cognition in nature and how might it have evolved? Historically, research on such questions has been fragmented between psychology, where the emphasis has been on theoretical models and lab experiments, and biology, where studies focus on evolution and the adaptive use of perception, learning, and decision-making in the field. Cognition, Evolution and the Study of Behavior integrates research from psychology, behavioral ecology, and ethology in a wide-ranging synthesis of theory and research about animal cognition in the broadest sense, from species-specific adaptations in fish to cognitive mapping in rats and honeybees to theories of mind for chimpanzees. As a major contribution to the emerging discipline of comparative cognition, the book is an invaluable resource for all students and researchers in psychology, zoology, behavioral neuroscience. It will also interest general readers curious about the details of how and why animals--including humans--process, retain, and use information as they do. Reviews “This book is a very comprehensive review of animal cognition. It differs from other texts on this topic in a number of ways, as outlined by Shettleworth in her preface and in the opening chapter. Essentially, Shettleworth wants to advocate an 'adaptationist or ecological approach to cognition'. In doing so, she brings together a wealth of data on animal cognition, studied from quite different theoretical viewpoints, such as cognitive ethology, animal learning theory, neuroscience, behavioural ecology and cognitive psychology. . . . Each chapter ends with a clear and useful summary, and helpful suggestions for further reading. The book's numerous illustrations, which are mostly tables or figures redrawn by Margaret Nelson, greatly add to its appeal. . . . [T]his is a marvellously rich, well-written and stimulating book. . . . I greatly enjoyed reading [and] recommend it highly to anyone interested in animal cognition, evolution and behaviour.”--Animal Behaviour “Sara Shettleworth has probably written the most comprehensive study of the animal mind ever and therefore a fundamental textbook on 'comparative cognition'. She first gets consciousness out of the way: whether an animal is conscious or not is impossible to determine, since consciousness is a private, subjective phenomenon. We can study cognition, and certainly cognition lends credibility to the idea that at least some animals must be at least to some degree conscious, but experiments can only prove facts about cognition. She reviews the field of cognitive ethology from the beginning and then analyzes the main cognitive tasks from an information-processing perspective By the end of her review of cognitive faculties, it become apparent that, at least among vertebrates, there are no significant differences in learning, except for language. All vertebrates are capable of 'associative' learning What no other vertebrate seems to be capable of is 'syntax'.” -- Piero Scaruffi, Thymos.com |
Shettleworth, S. J. (2005). Taking the best for learning. Behav. Process., 69(2), 147–9; author reply 159–63.
Abstract: Examples of how animals learn when multiple, sometimes redundant, cues are present provide further examples not considered by Hutchinson and Gigerenzer that seem to fit the principle of taking the best. “The best” may the most valid cue in the present circumstances; evolution may also produce species-specific biases to use the most functionally relevant cues.
Keywords: *Algorithms; Animals; *Behavior, Animal; Decision Making; Evolution; *Learning; *Models, Theoretical
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Anderson, M. C., & Shettleworth, S. J. (1977). Behavioral adaptation to fixed-interval and fixed-time food delivery in golden hamsters. J Exp Anal Behav, 27(1), 33–49.
Abstract: Food-deprived golden hamsters in a large enclosure received food every 30 sec contingent on lever pressing, or free while their behavior was continuously recorded in terms of an exhaustive classification of motor patterns. As with other species in other situations, behavior became organized into two main classes. One (terminal behaviors) increased in probability throughout interfood intervals; the other (interim behaviors) peaked earlier in interfood intervals. Which class an activity belonged to was independent of whether food was contingent on lever pressing. When food was omitted on some of the intervals (thwarting), the terminal activities began sooner in the next interval, and different interim activities changed in different ways. The interim activities did not appear to be schedule-induced in the usual sense. Rather, the hamsters left the area of the feeder when food was not due and engaged in activities they would normally perform in the experimental environment.
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Hampton, R. R., & Shettleworth, S. J. (1996). Hippocampus and memory in a food-storing and in a nonstoring bird species. Behav Neurosci, 110(5), 946–964.
Abstract: Food-storing birds maintain in memory a large and constantly changing catalog of the locations of stored food. The hippocampus of food-storing black-capped chickadees (Parus atricapillus) is proportionally larger than that of nonstoring dark-eyed juncos (Junco hyemalis). Chickadees perform better than do juncos in an operant test of spatial non-matching-to-sample (SNMTS), and chickadees are more resistant to interference in this paradigm. Hippocampal lesions attenuate performance in SNMTS and increase interference. In tests of continuous spatial alternation (CSA), juncos perform better than chickadees. CSA performance also declines following hippocampal lesions. By itself, sensitivity of a given task to hippocampal damage does not predict the direction of memory differences between storing and nonstoring species.
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Shettleworth, S. J., & Westwood, R. P. (2002). Divided attention, memory, and spatial discrimination in food-storing and nonstoring birds, black-capped chickadees (Poecile atricapilla) and dark-eyed juncos (Junco hyemalis). J Exp Psychol Anim Behav Process, 28(3), 227–241.
Abstract: Food-storing birds, black-capped chickadees (Poecile atricapilla), and nonstoring birds, dark-eyed juncos (Junco hyemalis), matched color or location on a touch screen. Both species showed a divided attention effect for color but not for location (Experiment 1). Chickadees performed better on location than on color with retention intervals up to 40 s, but juncos did not (Experiment 2). Increasing sample-distractor distance improved performance similarly in both species. Multidimensional scaling revealed that both use a Euclidean metric of spatial similarity (Experiment 3). When choosing between the location and color of a remembered item, food storers choose location more than do nonstorers. These results explain this effect by differences in memory for location relative to color, not division of attention or spatial discrimination ability.
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Shettleworth, S. J., & Juergensen, M. R. (1980). Reinforcement and the organization of behavior in golden hamsters: brain stimulation reinforcement for seven action patterns. J Exp Psychol Anim Behav Process, 6(4), 352–375.
Abstract: Golden hamsters were reinforced with intracranial electrical stimulation of the lateral hypothalamus (ICS) for spending time engaging in one of seven topographically defined action patterns (APs). The stimulation used as reinforcer elicited hoarding and/or feeding and supported high rates of bar pressing. In Experiment 1, hamsters were reinforced successively for digging, open rearing, and face washing. Digging increased most in time spent, and face washing increased least. Experiments 2-5 examined these effects further and also showed that “scrabbling,” like digging, was performed a large proportion of the time, almost without interruption, for contingent ICS but that scratching the body with a hindleg and scent-marking showed relatively little effect of contingent ICS, the latter even in an environment that facilitated marking. In Experiment 6, naive hamsters received ICS not contingent on behavior every 30 sec (fixed-time 30-sec schedule). Terminal behaviors that developed on this schedule were APs that were easy to reinforce in the other experiments, but a facultative behavior, face washing, was one not so readily reinforced. Experiment 7 confirmed a novel prediction from Experiment 6--that wall rearing, a terminal AP, would be performed at a high level for contingent ICS. All together, the results point to both motivational factors and associative factors being involved in the considerable differences in performance among different reinforced activities.
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