Equine and Animal Cognition Reference Database -- Query Results

	Equine and Animal Cognition Reference Database Home \| Show All \| Simple Search \| Advanced Search	Login Quick Search: Field: contains: ...
	1-10 of 28 records found matching your query:

Search & Display Options

Select All Deselect All

<< 1 2 3 >>

List View

Citations

Details

	Records
	Author	Astié, A.A.; Kacelnik, A.; Reboreda, J.C.
	Title	Sexual differences in memory in shiny cowbirds			Type	Journal Article
	Year	1998	Publication	Animal Cognition	Abbreviated Journal	Anim. Cogn.
	Volume	1	Issue	2	Pages	77-82
	Keywords
	Abstract	Avian brood parasites depend on other species, the hosts, to raise their offspring. During the breeding season, parasitic cowbirds (Molothrus sp.) search for potential host nests to which they return for laying a few days after first locating them. Parasitic cowbirds have a larger hippocampus/telencephalon volume than non-parasitic species; this volume is larger in the sex involved in nest searching (females) and it is also larger in the breeding than in the non-breeding season. In nature, female shiny cowbirds Molothrus bonariensis search for nests without the male's assistance. Here we test whether, in association with these neuroanatomical and behavioural differences, shiny cowbirds display sexual differences in a memory task in the laboratory. We used a task consisting of finding food whose location was indicated either by the appearance or the location of a covering disk. Females learnt to retrieve food faster than males when food was associated with appearance cues, but we found no sexual differences when food was associated with a specific location. Our results are consistent with the view that parasitism and its neuroanatomical correlates affect performance in memory tasks, but the effects we found were not in the expected direction, emphasising that the nature of avian hippocampal function and its sexual differences are not yet understood.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3158
Permanent link to this record



	Author	Bateson, M.; Kacelnik, A.
	Title	Starlings' preferences for predictable and unpredictable delays to food			Type	Journal Article
	Year	1997	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	53	Issue	6	Pages	1129-1142
	Keywords
	Abstract	Risk-sensitive foraging theory is based on the premise that unpredictable runs of good or bad luck can cause a variable food source to differ in fitness value from a fixed food source yielding the same average rate of gain but no unpredictability. Thus, risk-sensitive predictions are dependent on the food intake from variable sources being not only variable but also unpredictable or `risky' in outcome. This study tested whether unpredictability is a component of the value that foraging starlings,Sturnus vulgarisattribute to food sources that are variable in the delay to obtain food. Two groups of birds chose between a fixed and a variable delay option; the variable option was unpredictable in the risky group and predictable in the risk-free group in the overall rate of intake it yielded. In both groups the fixed option was adjusted by titration to quantify the magnitude of preference for predictable and unpredictable variance. On negative energy budgets both groups were significantly risk-prone, with the risky group being significantly more risk-prone than the risk-free group. Switching the birds to positive budgets by doubling the size of each food reward had no significant effect on preference, and similar trends to those found with negative budgets were observed. These results are not readily explained by risk-sensitive foraging theory, but may be explained by the algorithm used by the birds to attribute value to average expected rewards.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2108
Permanent link to this record



	Author	Bateson, M.; Kacelnik, A.
	Title	Accuracy of memory for amount in the foraging starling,Sturnus vulgaris			Type	Journal Article
	Year	1995	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	50	Issue	2	Pages	431-443
	Keywords
	Abstract	Attempts to include psychological constraints in models of foraging behaviour differ in their assumptions concerning the accuracy of estimation of environmental parameters. Psychologists model estimation error as increasing linearly with the magnitude of a stimulus (Weber's Law), whereas behavioural ecologists either ignore error or assume it to be independent of stimulus magnitude. Studies on the estimation of time intervals have confirmed Weber's Law, but there are few data on the accuracy of estimation of amounts of food. Since the currency of most foraging models is the amount of food acquired per unit of time spent foraging, information on estimation of amount is required. Here, a titration method was used in which starlings chose between two cues. One colour signalled a standard food reward, and the other a reward that adjusted in magnitude according to the birds' choices: it increased when the standard was preferred and decreased when the adjusting option was preferred. There were two standards of 3 and 9 units of food, each of which was delivered at two rates to control for possible effects of rate of reinforcement on discrimination. The observed value of the adjusting option oscillated around a mean value slightly larger than that of the standard. The amplitude and period of these oscillations were larger when the standard was larger, independent of the rate of reinforcement. Also, molecular analysis showed that the probability of choosing the currently larger alternative increased as the relative difference between the adjusting option and standard increased. These results are consistent with Weber's Law applying to starlings' memories for amounts of food.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2110
Permanent link to this record



	Author	Beauchamp, G.; Kacelnik, A.
	Title	Effects of the knowledge of partners on learning rates in zebra finches Taeniopygia guttata			Type	Journal Article
	Year	1991	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	41	Issue	2	Pages	247-253
	Keywords
	Abstract	Many interpretations of the adaptive value of group living involve tranfer of knowledge. However, according to learning theory, being in a pair with a knowledgeable partner can have paradoxical consequences. Obtaining food by following a skilled companion may reduce the ability of naive individuals to learn about clues that signal the occurrence of food. This study examined the relation between learning and following in paris of zebra finches. Knowledgeable partners were trained to obtain food from a computer-controlled dispenser by using the information provided by a signal. For non-knowledgeable partners, the signal was irrelevant and could not be used to predict foraging opportunities. The rate of learning about the signal by naive birds that shared the experience of either knowledgeable or nonknowledgeable tutors was then examined. Naive birds learned more slowly as a result of being in a pair with a knowledgeable than a non-knowledgeable partner. Well-informed mates acted as a reliable cue to predict foraging opportunities, and thus overshadowed the independent signal. The knowledge of a partner influences learning rates in naive individuals, but in the opposite direction to that predicted by earlier accounts of learning in social contexts.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2115
Permanent link to this record



	Author	Brunner, D.; Kacelnik, A.; Gibbon, J.
	Title	Memory for inter-reinforcement interval variability and patch departure decisions in the starling,Sturnus vulgaris			Type	Journal Article
	Year	1996	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	51	Issue	5	Pages	1025-1045
	Keywords
	Abstract	An experiment with starlings was conducted to investigate the effect of variability in inter-reinforcement intervals on foraging decisions. The experimental design simulated an environment in which food was distributed in patches. Patches contained zero to four food items which could be collected by pecking at a key. All patches ended with sudden depletion. The time elapsed since the last reinforcement was the only way to detect the depletion of the patch. Once a patch was depleted, a new patch could be reached by completion of a travel requirement of 20 flights between two perches. Key pecks within a patch and the time of the last response in a patch (giving-in time) were recorded. The level of variability in the inter-reinforcement intervals was varied between different conditions. An increase in inter-reinforcement interval variability resulted in a flattening of response rate functions and giving-in time distributions, and in more asymmetry of the response functions, but not of the giving-in time distributions. Two theoretical models of decision making are presented, which differ in the assumptions about memory constraints. In one case, all inter-reinforcement intervals are remembered but in the other, only the intervals with extreme values are remembered. Both models accommodate response rates as a function of trial time, but only the second is compatible with the observed departure decision. Our results are compatible with net rate maximization.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2109
Permanent link to this record



	Author	Brunner, D.; Kacelnik, A.; Gibbon, J.
	Title	Optimal foraging and timing processes in the starling, Sturnus vulgaris: effect of inter-capture interval			Type	Journal Article
	Year	1992	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	44	Issue	4	Pages	597-613
	Keywords
	Abstract	Laboratory experiments with starlings, Sturnus vulgaris, were conducted to investigate the interaction between timing and cost-benefit considerations. The design simulated an environment in which food was distributed in patches. Patches contained a random number of food items (N=0-4) separated by a fixed inter-capture interval or fixed interval. All patches ended with sudden depletion. The time elapsed since the last prey capture was the only way to detect the depletion of the patch. Once the patch was depleted a new patch could be reached by travelling between two perches. Three measures of timing were taken: (1) rate of working for food as function of `waiting' time in a patch, (2) the time of the last response in a patch or `giving-in' time, and (3) the time at which travel was initiated or `moving-on' time. The fixed interval that characterized patches was varied between conditions. The mean time of the peak in working rate was consistently centred around the fixed interval, while the other two measures of timing kept a roughly linear relation to the fixed interval, with slope greater than one. In accordance with Scalar Expectancy Theory, variability in the three forms of timing was proportional to the magnitude of the fixed interval. The birds seemed to take account of this increase in variability as shown by the mean value of their giving-up criterion. These results imply that information-processing constraints are important for modelling behavioural optimality.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2112
Permanent link to this record



	Author	Caraco, T.; Kacelnik, A.; Mesnick, N.; Smulewitz, M.
	Title	Short-term rate maximization when rewards and delays covary			Type	Journal Article
	Year	1992	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	44	Issue	Part 3	Pages	441-447
	Keywords
	Abstract	In nature foragers must exploit resources that vary randomly in both the energy acquired per item (reward) and the time required to pursue, capture and process an item (delay). Furthermore, rewards and delays associated with particular resources may often covary significantly. An analytical model asks how variance-covariance levels for rewards and delays could influence choice of resources when lack of information or cognitive limitation implies that a consumer attempts to maximize its short-term rate of energy gain. Both greater expected reward and reduced expected delay clearly should enhance preference for a resource. The model predicts that increased delay variance and reduced reward-delay covariance should increase a forager's preference for a resource. A forager should be risk-averse towards reward variance when the reward-delay covariance is positive, but should become risk-prone towards reward variance when the reward-delay covariance is negative.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2113
Permanent link to this record



	Author	Cassini, M.H.; Kacelnik, A.; Segura, E.T.
	Title	The tale of the screaming hairy armadillo, the guinea pig and the marginal value theorem			Type	Journal Article
	Year	1990	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	39	Issue	6	Pages	1030-1050
	Keywords
	Abstract	Foraging by screaming hairy armadillos, Chaetophractus vellerosus, and guinea pigs, Cavia porcellus, was studied in the laboratory. The main question was whether patch exploitation varies with overall capture rate as predicted by the marginal value theorem (MVT). Armadillos in experiment I and guinea pigs in experiment II experienced a single travel time between depleting patches of two kinds: good and poor. There were two treatments, which differed in the quality of poor patches. MVT predicts that within a treatment, more prey should be taken from good than from poor patches and between treatments, good patches should be exploited in inverse relation to the quality of poor patches and poor patches should be exploited in direct relation to their own quality. In experiment III, guinea pigs experienced three treatments which differed in the travel requirement, while the two patch types remained the same. MVT predicts that within a treatment more prey should be taken from good than from poor patches and that between treatments more prey should be taken from both patch types as travel requirement increases. The qualitative predictions were supported in the three experiments. The quantitative fit was good but there was a bias towards more severe patch exploitation than predicted. The results indicate that in these species patch exploitation depends on overall food availability as predicted by the MVT when overall food availability differs either because of patch type composition or because of differences in travel requirement between patches.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2120
Permanent link to this record



	Author	Chappell, J.; Kacelnik, A.
	Title	Selection of tool diameter by New Caledonian crows Corvus moneduloides			Type	Journal Article
	Year	2004	Publication	Animal Cognition	Abbreviated Journal	Anim. Cogn.
	Volume	7	Issue	2	Pages	121-127
	Keywords	Animals; Behavior, Animal; Choice Behavior; Discrimination Learning; Feeding Behavior; Female; Functional Laterality; Manufactured Materials; Plant Leaves; Problem Solving; Songbirds; Technology
	Abstract	One important element of complex and flexible tool use, particularly where tool manufacture is involved, is the ability to select or manufacture appropriate tools anticipating the needs of any given task-an ability that has been rarely tested in non-primates. We examine aspects of this ability in New Caledonian crows-a species known to be extraordinary tool users and manufacturers. In a 2002 study, Chappell and Kacelnik showed that these crows were able to select a tool of the appropriate length for a task among a set of different lengths, and in 2002, Weir, Chappell and Kacelnik showed that New Caledonian crows were able to shape unfamiliar materials to create a usable tool for a specific task. Here we examine their handling of tool diameter. In experiment 1, we show that when facing three loose sticks that were usable as tools, they preferred the thinnest one. When the three sticks were presented so that one was loose and the other two in a bundle, they only disassembled the bundle when their preferred tool was tied. In experiment 2, we show that they manufacture, and modify during use, a tool of a suitable diameter from a tree branch, according to the diameter of the hole through which the tool will have to be inserted. These results add to the developing picture of New Caledonian crows as sophisticated tool users and manufacturers, having an advanced level of folk physics.
	Address	Department of Zoology, South Parks Road, OX1 3PS, Oxford, UK. jackie.chappell@zoo.ox.ac.uk
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1435-9448	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:15069612			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2528
Permanent link to this record



	Author	Chappell, J.; Kacelnik, A.
	Title	Tool selectivity in a non-primate, the New Caledonian crow (Corvus moneduloides)			Type	Journal Article
	Year	2002	Publication	Animal Cognition	Abbreviated Journal	Anim. Cogn.
	Volume	5	Issue	2	Pages	71-78
	Keywords	Adaptation, Psychological; Animals; Cognition; Female; Learning; Male; Perception; *Songbirds
	Abstract	We present an experiment showing that New Caledonian crows are able to choose tools of the appropriate size for a novel task, without trial-and-error learning. This species is almost unique amongst all animal species (together with a few primates) in the degree of use and manufacture of polymorphic tools in the wild. However, until now, the flexibility of their tool use has not been tested. Flexibility, including the ability to select an appropriate tool for a task, is considered to be a hallmark of complex cognitive adaptations for tool use. In experiment 1, we tested the ability of two captive birds (one male, one female), to select a stick (from a range of lengths provided) matching the distance to food placed in a horizontal transparent pipe. Both birds chose tools matching the distance to their target significantly more often than would be expected by chance. In experiment 2, we used a similar task, but with the tools placed out of sight of the food pipe, such that the birds had to remember the distance of the food before selecting a tool. The task was completed only by the male, who chose a tool of sufficient length significantly more often than chance but did not show a preference for a matching length.
	Address	Department of Zoology, University of Oxford, South Parks Road, Oxford OXI 3PS, UK. jackie.chappell@zoo.ox.ac.uk
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1435-9448	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:12150038			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2606
Permanent link to this record

Select All Deselect All

<< 1 2 3 >>

Details

CQL Search | Library Search | Show Record | Extract Citations

Help