Acoustic salience in emotional voice perception and its relationship with hallucination proneness

Auditory verbal hallucinations (AVH) are reported in approximately 70% of psychotic patients, but they also may occur in approximately 10% of the healthy general population. AVH have been related to altered processing of vocal emotions at both sensory and higher-order processing stages in psychotic patients. However, it remains to be clarified whether individuals with high hallucination proneness (HP) exhibit a similar pattern of alterations. We investigated the impact of HP on vocal emotional perception and specified whether manipulations of acoustic cues, such as sound intensity and duration, related to salience changes, affect the time course of voice processing reflected in event-related potentials (ERP) of the electroencephalogram. Participants varying in HP performed a task involving the categorization of emotional nonverbal vocalizations (neutral, anger, and amusement) differing in duration and intensity. ERP results demonstrated interactive effects of HP, valence, and acoustic cues on both early (N1, P2) and late (Late Positive Potential [LPP]) processing stages. Higher HP was associated with decreased N1 and increased P2 amplitudes in response to louder and longer neutral (vs. positive) vocalizations, as well as with a larger LPP to louder and longer negative (vs. neutral) vocalizations. These findings suggest that HP is associated with changes in the processing of vocal emotions that might be related to altered salience of acoustic representations of emotions. Consistent with prior studies with psychotic patients, these findings show that altered perception of vocal emotions may additionally contribute to the experience of hallucinations in nonclinical samples.