Origins and Functions of the Nonverbal Pride and Shame Expressions
This line of research examines the evolutionary origins and functions of the pride and shame expressions. Completed research in this vein includes work with former lab member Azim Shariff (now an Assistant Professor at UC Irvine) on the status signaling functions of pride and shame displays (Shariff & Tracy, 2009; Shariff, Tracy, & Markusoff, in press; Tracy, Shariff, Zhao, & Henrich, in press). In ongoing research led by Jason Martens, and in collaboration with Dr. Adam Anderson (University of Toronto), we are examining why the pride expression looks the way it does. For instance, why does the display include an expanded chest? Building on the Two-Stage Model, developed by Azim and Jess (Shariff & Tracy, 2011a; Shariff & Tracy, 2011b), we argue that the pride and shame displays may have initially evolved for their physiological functions, and only later become a signal. We are currently examining what physiological benefits pride might have originally served. In related work, Jason recently conducted a series of studies testing whether pride displays serve valuable functions for observers, as well as displayers. Drawing on a theoretical account we recently articulated (Martens, Tracy, & Shariff, 2012), we conducted a series of studies testing whether the pride display might cue learning opportunities. Studies conducted thus far support this account (Martens & Tracy, in press). In another line of studies in this vein, Jason, Jess, and Joey Cheng are collaborating with primatologist Dr. Lisa Parr (Emory) to test whether the chimpanzees dominance display might be homologous with human pride displays. This exciting set of studies is examining the extent to which chimps display expressions that are morphologically similar to pride displays, in analogous situations. Evidence in support of this hypothesis would provide clues about the early evolutionary origins of pride displays.