I presented a paper at the 2008 meeting of the International Primatological Society entitled "Facial expression and social organization in Macaca: a phylogenetic comparative analysis." My presentation was part of a symposium on facial expression entitled "Facial expression in primates: measurement, meaning and function." Here is a description of the symposium:
Primates send and receive an array of facial signals in order to navigate their social environments, and these communicative systems have undoubtedly been influential in the evolution of both primate mind and society. Yet facial expression is a relatively understudied mode of primate communication. Several recent developments have increased our understanding of facial signals, in terms of what they communicate, how they interact with other communicative modalites and how they have evolved. In this symposium, scientists studying facial expression in primates (including humans) from a variety of different perspectives will present their theoretical positions, methodological innovations and recent findings. The overarching goals are to present the form and function of facial expressions in different species, examine different approaches in the study of facial expression, and ultimately to identify the specific role facial expressions play in the lives of primates.
The symposium was organized by Bridget Waller, Sarah-Jane Vick, and Lisa Parr. The other participants included Jan van Hooff, Karen Schmidt, Amy Pollick, Elisabetta Palagi, and Matthew Campbell.