Opening social interactions: The coordination of gaze, vocalisations and greeting behaviour during handshakes – Ottilie Tilston

Social interactions do not begin by people simply starting to speak. Rather, participants negotiate the start of social interactions using verbal and non-verbal cues that constitute greeting behaviour. Handshakes are a common component of greeting behaviour. However, they are also complex sequences that must be coordinated on-the-fly. Like many other physical-contact greetings, handshakes involve gaze to coordinate movement. But gaze is also an important social signal. So how do humans deal with this dual use of gaze? This can be described as a resource allocation problem: we must look at the other person’s hand to ensure we do not miss it while also managing our gaze in a socially appropriate way. This study uses mobile eye tracking technology to shed light on the ways people use gaze behaviour to coordinate handshake greetings, teasing apart the effects of these two forces. This study introduces pairs of previously unacquainted participants wearing eye tracking glasses (ETGs) to measure precisely how gaze ties into other verbal and non-verbal greeting behaviours, combining the precision of laboratory conditions with naturalistic observation. Eye visibility, and therefore the possibility of direct mutual gaze, was manipulated using shaded lens inserts for the ETGs. Participants wearing shades had their faces looked at proportionally longer than participants who had their eyes visible. Participants gazed at their partner’s hand in the second prior to the handshake grasp, specifically in the first half of that second. Insight is provided regarding the systematic coordination of greeting vocalisations, and the extent to which they adhere to conventional models of conversational turn-taking