Individual recognition: it is good to be different.

Department of Ecology and Evolutionary Biology, University of Michigan, 830 N. University, Ann Arbor, MI 48109-1048, USA.
Trends in Ecology & Evolution (Impact Factor: 15.35). 11/2007; 22(10):529-37. DOI: 10.1016/j.tree.2007.09.001
Source: PubMed

ABSTRACT Individual recognition (IR) behavior has been widely studied, uncovering spectacular recognition abilities across a range of taxa and modalities. Most studies of IR focus on the recognizer (receiver). These studies typically explore whether a species is capable of IR, the cues that are used for recognition and the specializations that receivers use to facilitate recognition. However, relatively little research has explored the other half of the communication equation: the individual being recognized (signaler). Provided there is a benefit to being accurately identified, signalers are expected to actively broadcast their identity with distinctive cues. Considering the prevalence of IR, there are probably widespread benefits associated with distinctiveness. As a result, selection for traits that reveal individual identity might represent an important and underappreciated selective force contributing to the evolution and maintenance of genetic polymorphisms.

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    Behaviour 01/2015; 152:593-614. DOI:10.1163/1568539X-00003244 · 1.40 Impact Factor
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    ABSTRACT: Discrimination of and memory for others' generous and selfish behaviors could be adaptive abilities in social animals. Dogs have seemingly expressed such skills in both direct and indirect interactions with humans. However, recent studies suggest that their capacity may rely on cues other than people's individual characteristics, such as the place where the person stands. Thus, the conditions under which dogs recognize individual humans when solving cooperative tasks still remains unclear. With the aim of contributing to this problem, we made dogs interact with two human experimenters, one generous (pointed towards the food, gave ostensive cues, and allowed the dog to eat it) and the other selfish (pointed towards the food, but ate it before the dog could have it). Then subjects could choose between them (studies 1-3). In study 1, dogs took several training trials to learn the discrimination between the generous and the selfish experimenters when both were of the same gender. In study 2, the discrimination was learned faster when the experimenters were of different gender as evidenced both by dogs' latencies to approach the bowl in training trials as well as by their choices in preference tests. Nevertheless, dogs did not get confused by gender when the experimenters were changed in between the training and the choice phase in study 3. We conclude that dogs spontaneously used human gender as a cue to discriminate between more and less cooperative experimenters. They also relied on some other personal feature which let them avoid being confused by gender when demonstrators were changed. We discuss these results in terms of dogs' ability to recognize individuals and the potential advantage of this skill for their lives in human environments.
    PLoS ONE 02/2015; 10(2):e0116314. DOI:10.1371/journal.pone.0116314 · 3.53 Impact Factor
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    ABSTRACT: The ability of animals to discriminate between individuals or groups of individuals (e.g., kin or nonkin) is an important component of many hypotheses proposed to explain the evolution of cooperation and benefits of group living. Previous studies in mammalian systems have demonstrated the use of vocal cues in individual recognition and discrimination. However, there are few such studies in birds. Previous avian studies have largely examined discrimination between different categories of individuals (e.g., mate vs. nonmate, offspring vs. non-offspring) while discrimination between individuals of the same category remain largely unexplored. Previous work has demonstrated that the contact calls of free-living apostlebirds (Struthidea cinerea) are individually distinct. Here, we demonstrate that apostlebirds can differentiate between the calls of other individuals of the same social group using vocal cues alone. These findings are biologically relevant as apostlebirds live in complex fission–fusion societies where social groups vary in size, sex ratio, number of breeders, and composition of related and unrelated members.

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Jan 7, 2015