Abstract
As a highly social species, humans regularly exchange sophisticated social signals to support everyday life and the functioning of wider society. One of the most important aspects of social interaction is communicating negative (i.e., pain) and positive (i.e., pleasure) internal states. Although pain and pleasure are diametrically opposite concepts (Russell, 1980), several studies claim that facial expressions of pain and pleasure are too similar to support communication (Aviezer, Trope, & Todorov, 2012; Hughes & Nicholson, 2008) thereby questioning their function as social signals (Fernández-Dols, Carrera, & Crivelli, 2011). Here, we address this question by modelling the dynamic facial expressions that represent pain and pleasure (i.e. orgasm) in two cultures (40 Western, 40 East Asian observers) using a dynamic facial expression generator (Yu, Garrod, & Schyns, 2012) and reverse correlation (Ahumada & Lovell, 1971; see Fig S1, Panel A; see also Gill, Garrod, Jack, & Schyns, 2014; Jack, Garrod, & Schyns, 2014; Jack, Garrod, Yu, Caldara, & Schyns, 2012). In each culture, comparison of the pain and orgasm dynamic facial expression patterns show that they comprise highly distinct (i.e. decorrelated) signals that observers from each culture can easily detect (measured with d-prime). In addition, cross-cultural analyses showed that pain facial expressions are highly similar within and across cultures (see Fig S1, Panel B), supporting views of their culturally common physiological roots (e.g., the gate-control hypothesis, Melzack & Wall, 1967). In contrast, orgasm facial expressions form distinct clusters within each culture, suggesting the contribution of cultural learning and their role as evolved social signals (Baumeister & Bratslavsky, 1999; Eibl-Eibesfeldt, 1989). Together, our data challenges the common view that facial expressions of pain and pleasure are indistinct, non-diagnostic signals of extreme positive and negative emotion, and provides insights into the biological and cultural basis of facial expressions of pain and pleasure.
Meeting abstract presented at VSS 2016