Moment-by-moment tracking of audience brain responses to an engaging public speech: Replicating the reverse-message engineering approach

Abstract

Public speaking engages and entertains audiences. Through neuroimaging, we can examine responses to speeches in real time. Replicating an earlier study, this study carries out two kinds of analyses–forward and reverse correlations. First, we examine how the soundwave carrying the speech relates to brain responses, finding that bilateral auditory cortex responses track with the speech signal’s energy. Second, we use the speech-evoked brain responses to reverse-identify salient moments in the speech. Specifically, we focus on the right temporoparietal junction (TPJ), a region associated with social cognition. We find that TPJ-peaks reverse-identify socially engaging content (defined by the ability to evoke laughter). These results demonstrate new ways to study the relationship between story content and the audience responses it evokes.