The uncanny valley of familiarly unfamiliar voices: challenges in replicating the Mere Exposure Effect with voices

The Mere Exposure Effect is an effect where repeated, unreinforced exposure to a stimulus leads to increased positive affect towards that stimulus. While the effect has been shown in static stimuli of person identity, such as faces, it is unclear if it applies to dynamic person identity representations such as human voices. In two studies (NS1 = 238 with spoken sentences, NS2 = 88 with spoken words) university students engaged in exposure, rating, and validation tasks. We observed increased liking of voices with 8 initial repetitions for the sentences. Voices initially presented 2 and 5 times were liked less than unfamiliar voices and recognised as familiar with less confidence than voices initially presented 8 times, forming an inverted “U” in likeability and familiarity. Less experience with the speaker’s accent weakened the inverted “U” in liking. Our words data are insufficient for inferential conclusions, but the sentences results indicate an uncanny valley of “familiarly unfamiliar” voices, which are more familiar than never heard stimuli but not familiar enough for the mere exposure effect of increased liking.