^* To investigate joint attention, researchers hide an object or food inside an opaque container and point at it with their finger. Babies fourteen months and older are able to locate the hidden item easily, but chimps find this task extremely challenging. Surprisingly, domestic dogs excel at solving the same problem. References: B. Hare et al. (1998), “Communication of Food Location Between Human and Dog (Canis familiaris),” Evolution of Communication 2: 137–59; A. Miklosi et al. (1998), “Use of Experimenter- Given Cues in Dogs,” Animal Cognition 1: 113–21.

^† Joint attention permeates every social interaction, in sophisticated and often subtle ways. Neuroscientist Sonya Babar and her colleagues found that when we look at somebody’s face, we shift our gaze between the two eyes of our partner, seeking the best eye contact. The eye we settle on at any given time tends to be the mirror image of the eye chosen by our interlocutor. For instance, if we sense that our partner’s eyes are focused on our right eye, we reflexively respond by shifting our gaze to her left eye. This joint shifting of gaze is perceived as proper eye contact. However, if a partner looks at our right eye as we look at her right eye, both of us will usually sense a break in eye contact or lack of attention. Reference: S. Babar et al. (2010), “Eye Dominance and the Mechanisms of Eye Contact,” Journal of AAPOS 14: 52–57.