The social complexity hypothesis for the evolution of communication posits that complex
social environments require greater communication complexity for individuals to effectively …

Lately, there has been a growing interest in studying domestic cat facial signals, but most of
this research has centered on signals produced during human-cat interactions or pain. The …

Long-term studies of well-identified individuals and improved methodologies have
advanced primate behavioral ecology, genetics, and physiology (Kappeler & Watts, 2012; …

The social complexity hypothesis for communicative complexity posits that animal societies
with more complex social systems require more complex communication systems. We tested …

Laugh faces of humans play a key role in everyday social interactions as a pervasive tool of
communication across contexts. Humans often vary the degree of mouth opening and teeth …

Social living affords primates (including humans) many benefits. Communication has been
proposed to be the key mechanism used to bond social connections, which could explain …

There has been an increased interest in standardized approaches to coding facial
movement in mammals. Such approaches include Facial Action Coding Systems (FACS) …

Facial communication regulates many aspects of social life in human and nonhuman
primates. Empirically identifying distinct facial expressions and their underlying functions …

The social complexity hypothesis for communicative complexity posits that animal societies
with more complex social systems require more complex communication systems. Here, we …

Primate social bonds are described as being especially complex in their nature, and
primates have unusually large brains for their body size compared to other mammals …