Abstract: The function of olfactory signalling in social species is less well understood than in asocial species. Consequently, we examined olfactory communication in the ringtailed lemur, a socially complex primate that retains a functional vomeronasal organ, has well-developed scent glands and shows a suite of scent-marking behaviour. To assess the information content of different types of scent gland secretions, we decoupled olfactory cues from the visual and behavioural modalities with which scent marking is normally associated. We presented male and female subjects (signal receivers) with a series of choice tests between odours derived from conspecific donors (signal senders) varying by sex, age, social status and reproductive condition. We additionally examined the influence of the receivers' reproductive state and familiarity with the signaller. The reproductive condition, social status and familiarity of senders and receivers affected signal transmission; specifically, male receivers attended most to the odours of conspecifics in breeding condition and to the odours of familiar, dominant animals. By contrast, females varied their responses according to both their own reproductive state and that of the sender. Based on male and female patterns of countermarking, we suggest that scent marking serves a function in intergroup spacing and intrasexual competition for both sexes, as might be expected in a female-dominant species. By contrast, minimal female interest in male odours counters a female mate choice function for scent marking in this species. Nevertheless, scent marks are critical to male-male competition and, therefore, may be subject to sexual selection.

Abstract: Cuttlefish have a large repertoire of body patterns that are used for camouflage and interspecific signaling. Intraspecific signaling by male cuttlefish has been well documented but studies on signaling by females are lacking. We found that females displayed a newly described body pattern termed Splotch toward their mirror image and female conspecifics, but not to males, prey or inanimate objects. Female cuttlefish may use the Splotch body pattern as an intraspecific signal, possibly to reduce agonistic interactions. The ability of females to produce a consistent body pattern in response to conspecifics and mirrors suggests that they can recognize same-sex conspecifics using visual cues, despite the lack of sexual dimorphism visible to human observers.

Abstract: Before accepting a configural or holistic account of visual perception, one should be sure that an analytic (elemental) account does not provide an equal or better explanation of the results. I suggest that when one forms a compound of a color and a line orientation with one element previously trained as an S+ and the other as an S-, the resulting transfer found will depend on the relative salience of the two elements, and most important, the similarity of the compound to each of the training stimuli. Thus, if a line orientation is placed on a colored background (a separable compound), it will appear more like the colored field used in training, and color will control responding. However, if the line itself is colored (an integral compound), the compound will appear more like the line used in training, and line orientation will control responding. Not only does this account do a better job of explaining the data but it is simpler and it is testable.

Abstract: The present work is part of a decade-long study on the spontaneous use of stones for cracking hard-shelled nuts by a semi-free-ranging group of brown capuchin monkeys (Cebus apella). Nutcracking events are frequently watched by other individuals--usually younger, less proficient, and that are well tolerated to the point of some scrounging being allowed by the nutcracker. Here we report findings showing that the choice of observational targets is an active, non-random process, and that observers seem to have some understanding of the relative proficiency of their group mates, preferentially watching the more skilled nutcrackers, which enhances not only scrounging payoffs, but also social learning opportunities.

Abstract: This study explored whether the tendency of chimpanzees and children to use emulation or imitation to solve a tool-using task was a response to the availability of causal information. Young wild-born chimpanzees from an African sanctuary and 3- to 4-year-old children observed a human demonstrator use a tool to retrieve a reward from a puzzle-box. The demonstration involved both causally relevant and irrelevant actions, and the box was presented in each of two conditions: opaque and clear. In the opaque condition, causal information about the effect of the tool inside the box was not available, and hence it was impossible to differentiate between the relevant and irrelevant parts of the demonstration. However, in the clear condition causal information was available, and subjects could potentially determine which actions were necessary. When chimpanzees were presented with the opaque box, they reproduced both the relevant and irrelevant actions, thus imitating the overall structure of the task. When the box was presented in the clear condition they instead ignored the irrelevant actions in favour of a more efficient, emulative technique. These results suggest that emulation is the favoured strategy of chimpanzees when sufficient causal information is available. However, if such information is not available, chimpanzees are prone to employ a more comprehensive copy of an observed action. In contrast to the chimpanzees, children employed imitation to solve the task in both conditions, at the expense of efficiency. We suggest that the difference in performance of chimpanzees and children may be due to a greater susceptibility of children to cultural conventions, perhaps combined with a differential focus on the results, actions and goals of the demonstrator.