Adam Anderson at McMaster

17 01 2015

Misha and I went to a great seminar at McMaster on Thursday: Adam Anderson was speaking in their Psychology Colloquium series on the sensory functions of facial expressions, especially those of fear and disgust. I saw him speak a couple of times while he was still at the University of Toronto (he recently moved to Cornell), and as ever, he was interesting and entertaining.

His research showing that fear expressions enlarge the visual field, while disgust expressions do the opposite, is a few years old now, but he’s since built on it by showing that they also affect visual processing (somehow, this was a bit vague: fear expressions increase sensivity while reducing precision, while disgust ones do the opposite?); that they affect air intake into the nose (he thinks he’s the only person ever to use fMRI to study the nares; he kept having to say to the technicians “No, no, NOT the brain, no! Focus on those empty spaces up the nose! Yes, really!”); and that they also influence how well others can follow your gaze, fear expressions greatly helping this.

Despite these communicative effects, however, Adam argues that altering sensory input, via this nares constriction and dilation and eye widening, is these expressions’ primary function  — with what they look like to others essentially being just a useful side-effect.

He’s also used clever maths and psychological contrast techniques to show that these two expressions are ‘opposites’ in terms of how they change the face (for example, if you add vectors describing them, the result is a neutral expression). Similar techniques reveal that happy and sad faces are likewise mathematical opposites (perhaps less surprising, this one), but whether they too have sensory effects is unknown. He’d like to think so, but here I suspect communication may be the primary function.

One other gem from this talk was his claim that people often misquote Darwin’s work on emotional expressions. Darwin apparently categorized emotions as pairs of opposites (like vector models), and emphasized that they might have functions aside from communication. I will have to read more…

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