Nathan Emery | Queen Mary, University of London (original) (raw)

Papers by Nathan Emery

A B S T R A C T Serial reversal learning of colour discriminations was assessed as an index of co... more A B S T R A C T Serial reversal learning of colour discriminations was assessed as an index of cognitive flexibility in two captive species of Neotropical parrots. Both species showed similar performances across serial reversals and no between species differences were observed. In a second task subjects' performances were assessed after they experienced either a low or high pre-reversal learning criterion. If reversal performances improve through processes of as-sociative learning, a high pre-reversal criterion is expected to strengthen previously learned associations and hence impede post-reversal performances. Conversely, highly reinforced associations may facilitate the use of conditional rules that can be generalised across reversals and improve post-reversal performances. We found that high criterion subjects made fewer post-reversal errors and required fewer trials to reach criterion, than low criterion subjects. Red-shouldered macaws and black-headed caiques may therefore demonstrate capacities for solving serial reversal problems by applying conditional rules, rather than learning solely by associative processes. Such performances coincide with findings in great apes, but contrast with findings in monkeys and prosimians, which generally show impaired reversal performances when trained to a highly rigorous pre-reversal criterion. Overall, these findings suggest an evolutionary convergence of cognitive flexibility between parrots and non-human great apes.

33 THE SOCIAL CONTEXT OF CONTACT CALLS BY ROOKS (CORVUS FRUGILEGUS) Alexandru MUNTEANU*, DVM Prof... more 33 THE SOCIAL CONTEXT OF CONTACT CALLS BY ROOKS (CORVUS FRUGILEGUS) Alexandru MUNTEANU*, DVM Professor Ionel PAPUC*, PhD Ira G. FEDERSPIEL**, PhD Professor Nicola S. CLAYTON***, PhD Nathan J. EMERY**, MD Abstract Communication is the ...

Behavioral Neuroscience, 2008

Naturwissenschaften, Jan 1, 2003

Journal of Experimental Psychology: …, Jan 1, 2009

Journal of Comparative …, Jan 1, 2006

Journal of …, Jan 1, 2006

Current Biology, Jan 1, 2009

Behaviour, Jan 1, 2007

Page 1. The role of food-and object-sharing in the development of social bonds in juvenile jackda... more Page 1. The role of food-and object-sharing in the development of social bonds in juvenile jackdaws (Corvus monedula) Auguste MP von Bayern 1) , Selvino R. de Kort 2,3) , Nicola S. Clayton 2) & Nathan J. Emery 1,4) ( 1 Sub ...

Origins of the Social Mind, Jan 1, 2008

Page 1. 65 4 How to Build a Scrub-Jay that Reads Minds Nathan J. Emery1 and Nicola S. Clayton2 1.... more Page 1. 65 4 How to Build a Scrub-Jay that Reads Minds Nathan J. Emery1 and Nicola S. Clayton2 1. Introduction Although the search for human-like theory of mind (ToM) in non-human animals has continued unabated for ...

Animal Behaviour, Jan 1, 2005

Food-caching western scrub-jays cache items themselves, and use observational spatial memory to s... more Food-caching western scrub-jays cache items themselves, and use observational spatial memory to steal the caches of others. Our aim in this study was to investigate the strategies used by scrub-jays to reduce cache theft by conspecifics. In three experiments, scrub-jays were allowed to cache wax worms in two different locations. In experiment 1, the birds preferred to hide items in distant sites when watched by another jay, but used near and distant sites equally when the observer's view was obscured by a screen. As conspecifics rely on observational spatial memory to steal other jays' caches, this use of distance might reduce the visual information available to the potential thief and thus decrease pilfering accuracy. Where possible, however, placing caches out of sight may be more effective. In experiment 2, storers cached predominantly in distant, out-of-view, sites. However, items placed in view of the observer were moved multiple times, possibly confusing the observer as to their location. In experiment 3, when in-view and out-of-view sites were equidistant to the observer, storers cached mainly in out-of-view sites when observed, but cached equally in both sites when not observed. In all three experiments, some items were cached in nonpreferred sites (near, in view). During recovery sessions, when the storer was not observed, these items were selectively recached in new sites unbeknown to the observer. It may be advantageous not to hide all the caches in one place, because unpredictability might provide the best insurance against pilfering.

Current Biology, Jan 1, 2007

Rational Animals, Jan 1, 2006

Animal Behaviour, Jan 1, 2008

… of the Royal …, Jan 1, 2007

Current Biology, Jan 1, 2006

Animal Cognition, Jan 1, 2007

A B S T R A C T Serial reversal learning of colour discriminations was assessed as an index of co... more A B S T R A C T Serial reversal learning of colour discriminations was assessed as an index of cognitive flexibility in two captive species of Neotropical parrots. Both species showed similar performances across serial reversals and no between species differences were observed. In a second task subjects' performances were assessed after they experienced either a low or high pre-reversal learning criterion. If reversal performances improve through processes of as-sociative learning, a high pre-reversal criterion is expected to strengthen previously learned associations and hence impede post-reversal performances. Conversely, highly reinforced associations may facilitate the use of conditional rules that can be generalised across reversals and improve post-reversal performances. We found that high criterion subjects made fewer post-reversal errors and required fewer trials to reach criterion, than low criterion subjects. Red-shouldered macaws and black-headed caiques may therefore demonstrate capacities for solving serial reversal problems by applying conditional rules, rather than learning solely by associative processes. Such performances coincide with findings in great apes, but contrast with findings in monkeys and prosimians, which generally show impaired reversal performances when trained to a highly rigorous pre-reversal criterion. Overall, these findings suggest an evolutionary convergence of cognitive flexibility between parrots and non-human great apes.

33 THE SOCIAL CONTEXT OF CONTACT CALLS BY ROOKS (CORVUS FRUGILEGUS) Alexandru MUNTEANU*, DVM Prof... more 33 THE SOCIAL CONTEXT OF CONTACT CALLS BY ROOKS (CORVUS FRUGILEGUS) Alexandru MUNTEANU*, DVM Professor Ionel PAPUC*, PhD Ira G. FEDERSPIEL**, PhD Professor Nicola S. CLAYTON***, PhD Nathan J. EMERY**, MD Abstract Communication is the ...

Behavioral Neuroscience, 2008

Naturwissenschaften, Jan 1, 2003

Journal of Experimental Psychology: …, Jan 1, 2009

Journal of Comparative …, Jan 1, 2006

Journal of …, Jan 1, 2006

Current Biology, Jan 1, 2009

Behaviour, Jan 1, 2007

Page 1. The role of food-and object-sharing in the development of social bonds in juvenile jackda... more Page 1. The role of food-and object-sharing in the development of social bonds in juvenile jackdaws (Corvus monedula) Auguste MP von Bayern 1) , Selvino R. de Kort 2,3) , Nicola S. Clayton 2) & Nathan J. Emery 1,4) ( 1 Sub ...

Origins of the Social Mind, Jan 1, 2008

Page 1. 65 4 How to Build a Scrub-Jay that Reads Minds Nathan J. Emery1 and Nicola S. Clayton2 1.... more Page 1. 65 4 How to Build a Scrub-Jay that Reads Minds Nathan J. Emery1 and Nicola S. Clayton2 1. Introduction Although the search for human-like theory of mind (ToM) in non-human animals has continued unabated for ...

Animal Behaviour, Jan 1, 2005

Food-caching western scrub-jays cache items themselves, and use observational spatial memory to s... more Food-caching western scrub-jays cache items themselves, and use observational spatial memory to steal the caches of others. Our aim in this study was to investigate the strategies used by scrub-jays to reduce cache theft by conspecifics. In three experiments, scrub-jays were allowed to cache wax worms in two different locations. In experiment 1, the birds preferred to hide items in distant sites when watched by another jay, but used near and distant sites equally when the observer's view was obscured by a screen. As conspecifics rely on observational spatial memory to steal other jays' caches, this use of distance might reduce the visual information available to the potential thief and thus decrease pilfering accuracy. Where possible, however, placing caches out of sight may be more effective. In experiment 2, storers cached predominantly in distant, out-of-view, sites. However, items placed in view of the observer were moved multiple times, possibly confusing the observer as to their location. In experiment 3, when in-view and out-of-view sites were equidistant to the observer, storers cached mainly in out-of-view sites when observed, but cached equally in both sites when not observed. In all three experiments, some items were cached in nonpreferred sites (near, in view). During recovery sessions, when the storer was not observed, these items were selectively recached in new sites unbeknown to the observer. It may be advantageous not to hide all the caches in one place, because unpredictability might provide the best insurance against pilfering.

Current Biology, Jan 1, 2007

Rational Animals, Jan 1, 2006

Animal Behaviour, Jan 1, 2008

… of the Royal …, Jan 1, 2007

Current Biology, Jan 1, 2006

Animal Cognition, Jan 1, 2007

Physical cognition has generally been assessed in tool-using species that possess a relatively la... more Physical cognition has generally been assessed in tool-using species that possess a relatively large brain size, such as corvids and apes. Parrots, like corvids and apes, also have large relative brain sizes, yet although parrots rarely use tools in the wild, growing evidence suggests comparable performances on physical cognition tasks. It is, however, unclear whether success on such tasks is facilitated by previous experience and training procedures. We therefore investigated physical comprehension of object relationships in two non-tool-using species of captive neotropical parrots on a new means-end paradigm, the Trap-Gaps task, using unfamiliar materials and modified training procedures that precluded procedural cues. Red-shouldered macaws (Diopsittaca nobilis) and black-headed caiques (Pionites melanocephala) were presented with an initial task that required them to discriminate between pulling food trays through gaps while attending to the respective width of the gaps and size of the trays. Subjects were then presented with a novel, but functionally equivalent, transfer task. Six of eight birds solved the initial task through trial-and-error learning. Four of these six birds solved the transfer task, with one caique demonstrating spontaneous comprehension. These findings suggest that non-tool-using parrots may possess capacities for sophisticated physical cognition by generalising previously learned rules across novel problems.