Brain responses to audiovisual speech mismatch in infants are associated with individual differences in looking behaviour

Research on audiovisual speech integration has reported high levels of individual variability, especially among young infants. In the present study we tested the hypothesis that this variability results from individual differences in the maturation of audiovisual speech processing during infancy. A developmental shift in selective attention to audiovisual speech has been demonstrated between 6 and 9 months with an increase in the time spent looking to articulating mouths as compared to eyes (Lewkowicz & Hansen-Tift. (2012) Proc. Natl Acad. Sci. USA, 109, 1431–1436; Tomalski et al. (2012) Eur. J. Dev. Psychol., 1–14). In the present study we tested whether these changes in behavioural maturational level are associated with differences in brain responses to audiovisual speech across this age range. We measured high-density event-related potentials (ERPs) in response to videos of audiovisually matching and mismatched syllables /ba/ and /ga/, and subsequently examined visual scanning of the same stimuli with eye-tracking. There were no clear age-specific changes in ERPs, but the amplitude of audiovisual mismatch response (AVMMR) to the combination of visual /ba/ and auditory /ga/ was strongly negatively associated with looking time to the mouth in the same condition. These results have significant implications for our understanding of individual differences in neural signatures of audiovisual speech processing in infants, suggesting that they are not strictly related to chronological age but instead associated with the maturation of looking behaviour, and develop at individual rates in the second half of the first year of life.

Emotional Responses to Disfigured Faces: The Influences of Perceived Anonymity, Empathy, and Disgust Sensitivity

Two experiments investigated self-reported emotional reactions to photographs of people with attractive, unattractive or structurally disfigured faces. In Experiment 1 participants viewing disfigured faces reported raised levels of sorrow and curiosity but not raised levels of negative emotions. In Experiment 2 there was more negative emotion and less positive emotion reported under conditions of relatively high anonymity, compared to low anonymity, specific to disfigured faces, suggesting that self-reports are influenced by social desirability. Trait empathy was associated with sorrow and negative emotions when viewing disfigured faces. Disgust sensitivity was associated with negative emotions and inversely associated with positive emotions.