The emotional and communicative significance of head nods

Head nods and shakes have been extracted from the SAL audiovisual database of spontaneous emotionally coloured dialogue. The dataset contains 154 nods and 104 shakes. Two trained observers rated them on multiple dimensions derived from linguistics on one hand, and the psychology of emotion on the other. One used audiovisual presentation, the other visual only. There was agreement on affective, but not linguistic significance – suggesting that the latter depends on speech context rather than the manner of movement per se. A few seem to form discrete types, but for the most part classical dimensional models of emotion captured the affective variation well.