An electrophysical marker for implicit trustworthiness perception in children

Trustworthiness is a primary dimension of facial first impressions and we are able to form an impression about how trustworthy someone is after just 33 ms of exposure. Our first impressions can strongly influence social interaction, and can even impact financial and court decisions. These face-based trust impressions are thought to emerge early – even seven month old infants are sensitive to variations in facial trustworthiness, and trust impressions mature across childhood, reflecting adult-like patterns by 10 to 13 years. Recently, Swe et al., (2020) showed that electrophysical cortical activity is triggered by variation in visually presented facial trustworthiness cues in adults, using the fast periodic visual stimulation (FPVS) electroencephalogram (EEG) technique. FPVS is an objective measure that provides high signal to noise ratio data and allows trust impressions to be examined implicitly and non-verbally. These characteristics make it a valuable method of examining early neural activity underlying children’s trust impressions from faces. Therefore, this study will investigate whether eight to nine year old children can percieve trustworthiness implicitly by examining their neural discrimination response to facial trustworthiness. Specifically, we will use an oddball paradigm where trustworthy faces will be shown at a base frequency of 6 Hz, followed by an oddball untrustworthy face at 1 Hz (and vice versa for the trustworthy oddball face trials; following Swe et al 2020). If children’s visual cortex is sensitive to the change in facial trustworthiness, there will be an increase in amplitude of neural activity at the oddball frequency (1 Hz), and its harmonics. We will include both an upright and inverted face stimuli condition to control for low-level information. We will also collect adults’ neural discrimination responses to facial trustworthiness, and compare child and adult groups’ responses to examine any developmental trends.