Accidentally catching the gaze of the person sitting opposite you on the subway can be a mortifying experience, although why people find eye contact so uncomfortable is a complicated question to answer. Facing this awkward issue head on, a team of researchers has now determined the limits of our ability to look others in the eye before things begin to feel weird, in an attempt to figure out the various factors affecting our tolerance to this tricky social experience.
Just under 500 people between the ages of 11 and 79 were invited to have their heads strapped in place while they watched a video of an actress staring directly into a camera for varying periods of time, before averting her gaze downwards. Participants were asked to press a button whenever they felt the actress had stared at them for an uncomfortably long or short period, while the researchers closely tracked their eye movements and pupil dilations.
The average “preferred gaze duration” (PGD) was found to be 3.3 seconds, as furtive glimpses lasting shorter than this were perceived as sneaky or suspicious, while longer stares were found to be overly intense or invasive.
In an attempt to figure out which factors affect the length of time that people are able to comfortably maintain eye contact, the study authors asked participants to rate the actress’s face for attractiveness, trustworthiness, threat, and dominance.
Publishing their findings in Royal Society Open Science, the researchers report that the only factor that had any bearing on PGD was threat, as people that perceived the actress’s face as threatening were quicker to become uncomfortable when meeting her eyes. This is somewhat surprising, since one might expect that a face’s attractiveness would also influence the amount of time others felt comfortable making eye contact.
The researchers also found that even though eye contact caused an involuntary pupil dilation in all participants, the pupils of those with a longer PGD tended to dilate quicker, suggesting that the speed of this dilation correlates to a person’s eagerness to maintain eye contact.
It is widely thought that facial recognition is mediated by brain regions such as the superior colliculus, which then transmits this information to the so-called “social brain”, consisting of the amygdala and a range of other structures. Because this communication is coordinated by the noradrenaline system, which is also known to control pupil dilation, it seems likely that the awkwardness we feel when gazing into people’s eyes is also a product of this system.
