STORRE

Social complexity is argued to be a driving factor in the evolution of communicative complexity. Complex social systems require individuals to form relationships with many conspecifics and interact in a wide variety of contexts over time, thus selecting for acoustic communication systems complex enough to facilitate these relationships. To better understand the evolution of such social and communicative complexity, we investigated a nocturnal, solitary forager, Garnett’s bushbaby (Otolemur ga...

Episodic memory is the ability to consciously recollect personal past events. This type of memory has been tested in non-human animals by using depletion paradigms that assess whether they can remember the "what," "where," and "when" (i.e., how long ago) of a past event. An important limitation of these behavioral paradigms is that they do not clearly identify the cognitive mechanisms (e.g., episodic memory, semantic memory) that underlie task success. Testing adult humans in a depletion para...

Grooming might be a resource that is offered in exchange for some benefit (e.g. access to a feeding site or coalitionary support) or it might be a mechanism for building and servicing social relationships, whose function, in turn, is to facilitate the exchange of resources and services. Bi-directional (or simultaneous mutual) grooming is unusually common among chimpanzees (though rare in other primates) and we suggest that this might be because it is an especially strong indicator of social b...

There is an ongoing debate about the adaptive function of chimpanzee's food-associated calls. Here, we tested a new hypothesis that food-associated calls in male chimpanzees function to signal that the calling individual is likely to initiate or prolong feeding. We propose that the signal functions to coordinate activities between individuals and that its ultimate function is to retain the nearby individuals in proximity. To test this hypothesis, we collected data on social and ecological cor...