Page 64 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 3
in emotion research. However, the smile is a communicative signal with meanings ranging from greeting another person, an expression of love, to a contemptuous smile or a sign of nervousness (Kret, 2015; Kret et al., 2020). Given that emotions can be expressed in multiple ways, the use of isolated stimuli in research leads to perceptual confounds, and therefore muddies the interpretation of results. Take for instance the observed attentional bias toward smiling faces. The question is whether we can be sure this attentional bias is related to the smile or whether it can be attributed to low-level characteristics of the included stimulus materials such as the exposure of the white teeth with the smile (Blanco et al., 2017). Further discussion about these debated topics is beyond the scope of this article. What we aim to do here is to take a step aside and study how emotional expressions are perceived from a large number of complex, naturalistic scenes depicting real life, authentic emotional situations, where emotional expressions are embedded within rich contextual features, thereby partly circumventing the above problems. This approach is ecologically more valid since in the natural world emotional expressions are always embedded in a scene (Kret & De Gelder, 2010).
The experience and expression of emotions is heavily reliant on contextual cues (Hess et al., 2016). The interpretation of facial expressions relies on contextual information, such as body language (Kret et al., 2013a, 2013b; Kret & De Gelder, 2013), outgroup cues (Kret & De Gelder, 2012b; Kret & Fischer, 2018; Liedtke et al., 2018) and the global processing of a social scene (Ngo & Isaacowitz, 2015; Righart & de Gelder, 2008; Van den stock et al., 2014). Likewise, the perception of emotional body language is influenced by the facial expression (Kret & De Gelder, 2012a) and the social context (Kret & De Gelder, 2010). In a study where participants were asked to explicitly label a person’s emotional expression, contextual influences on emotion perception varied based on the type of contextual cue, cue relevance, and the perceiver’s age (Ngo & Isaacowitz, 2015). EEG studies have demonstrated that the integration of these different pieces of information occurs early in the processing stream, further underscoring its relevance (De Gelder et al., 2006; Righart & de Gelder, 2008; Righart & De Gelder, 2008). Moreover, the perceived valence and arousal from such scenes is modulated by gender (for a review, see Kret & De Gelder, 2012a) and age (e.g., Backs et al., 2005). The dot-probe paradigm is widely used to measure attentional biases toward certain stimulus categories such as expressions of emotion. An advantage is its implicitness and simplicity, so that it can be administered in young children or nonhuman primates (Kret et al., 2016). A recent meta-analysis (of 38 articles including 4,221 children) confirmed that children show a significantly greater bias to threat-
62