Trait evaluations of faces and voices: Comparing within- and between-person variability

The human face and voice are rich sources of information that can vary in many different ways. Most of the literature on face/voice perception has focussed on understanding how people look and sound different to each other (between-person variability). However, recent studies highlight the ways in which the same person can look and sound different on different occasions (within-person variability). Here, in a series of three experiments, we aimed to establish how within- and between-person variability relate to one another in the context of social trait impressions by collecting social trait ratings attributed to multiple different face images and voice recordings of the same people. We find that within-person variability in social trait evaluations is at least as great as between-person variability. Using different stimulus sets in each experiment, we consistently find that trait impressions of voices are more variable within people than between people – a pattern that is only evident occasionally when judging faces. Our findings highlight the importance of understanding within-person variability, showing how judgements of the same person can vary widely on different encounters, and quantifying how this pattern differs for the perception of voices and faces.