Abstract: It has been proposed that levels of fluctuating asymmetry (FA) may be used in establishing and maintaining dominance hierarchies, as asymmetry reflects aspects of individual quality. However, previous manipulations of FA have failed to reveal that the level or outcome of agonistic intra-sexual interactions are affected by levels of FA. In female European starlings (Sturnus vulgaris), correlational data suggest that FA of the speckled chest plumage may be related to dominance status. These data are confounded, however, by total number of spots on the chest and the proportion of the chest that is white, both of which positively covary with chest asymmetry. Thus, we deconfounded the effects of these plumage traits on dominance by experimentally manipulating the number of spots and spot number asymmetry in a factorial design. The results indicated that dominance is influenced by the number of spots on the chest, but not by spot asymmetry. Birds with spottier chests were dominant over birds with experimentally decreased spot number. We suggest that female starlings' chests are exposed to extensive abrasion throughout the breeding season and so are susceptible to damage asymmetries that may mask the `true' fluctuating asymmetry of the trait. This may devalue the use of chest asymmetry as a quality indicator. Spottier chests may be costly to maintain, in part because of increased susceptibility to abrasion, and so may be a better indicator of quality than asymmetry.

Abstract: Chimpanzees (Pan troglodytes) sometimes help both humans and conspecifics in experimental situations in which immediate selfish benefits can be ruled out. However, in several experiments, chimpanzees have not provided food to a conspecific even when it would cost them nothing, leading to the hypothesis that prosociality in the food-provisioning context is a derived trait in humans. Here, we show that chimpanzees help conspecifics obtain both food and non-food items—given that the donor cannot get the food herself. Furthermore, we show that the key factor eliciting chimpanzees' targeted helping is the recipients' attempts to either get the food or get the attention of the potential donor. The current findings add to the accumulating body of evidence that humans and chimpanzees share the motivation and skills necessary to help others in situations in which they cannot selfishly benefit. Humans, however, show prosocial motives more readily and in a wider range of contexts.

Abstract: Gaze following is a behavior that draws the human infant into perceptual contact with objects or events in the world to which others are attending One interpretation of the development of this phenomenon is that it signals the emergence of joint or shared attention, which may be critical to the development of theory of mind An alternative interpretation is that gaze following is a noncognitive mechanism that exploits social stimuli in order to orient the infant (or adult) to important events in the world We report experimental results that chimpanzees display the effect in response to both movement of the head and eyes in concert and eve movement alone Additional tests indicate that chimpanzees appear able to (a) project an imaginary line of sight through invisible space and (b) understand How that line of sight can be impeded by solid, opaque objects This capacity may have arisen because of its reproductive payoffs in the context of social competition with conspecifics, predation avoidance, or both.

Abstract: This paper reviews the reasons why domestic dogs make good models to investigate cognitive processes related to social living and describes experimental approaches that can be adopted to investigate such processes in dogs. Domestic dogs are suitable models for investigating social cognition skills for three broad reasons. First, dogs originated from wolves, social animals that engage in a number of co-operative behaviours, such as hunting and that may have evolved cognitive abilities that help them predict and interpret the actions of other animals. Second, during domestication dogs are likely to have been selected for mental adaptations for their roles in human society such as herding or companionship. Third, domestic dogs live in a human world and “enculturation” may facilitate the development of relevant mental skills in dogs. Studies of social cognition in animals commonly use experimental paradigms originally developed for pre-verbal human infants. Preferential gaze, for example, can be used as a measure of attention or “surprise” in studies using expectancy violation. This approach has been used to demonstrate simple numerical competence in dogs. Dogs also readily use both conspecific and human social signals (e.g. looking or pointing) as information sources to locate hidden rewards such as food or favourite toys. Such abilities make dogs particularly good models for investigating perspective-taking tasks, where animals are required to discriminate between apparently knowledgeable and apparently ignorant informants.