Preferential decoding of emotion from human non-linguistic vocalizations versus speech prosody

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychophysiology

Background:

• Emotion processing is crucial for social interaction.
• The neurocognitive mechanisms differentiating vocalizations and speech prosody remain unclear.
• Evolutionary perspectives suggest primitive vocal signals may receive preferential processing.

Purpose of the Study:

• To compare the neural processing time course of emotions conveyed by non-linguistic vocalizations versus speech prosody.
• To investigate whether the neurocognitive system prioritizes vocalizations over speech.
• To examine the influence of trait anxiety on the processing of vocal emotions.

Main Methods:

• Event-related potentials (ERPs) were recorded using EEG during passive listening.
• Participants were exposed to vocalizations and pseudo-utterances expressing anger, sadness, or happiness.
• Analysis focused on ERP components (N100, P200, late positive component) and their interaction with expression type and emotion.

Main Results:

• Vocalizations and speech were differentiated early at the N100 component.
• Vocalizations elicited stronger, earlier, and more differentiated P200 responses compared to speech.
• Anger vocalizations evoked a stronger late positivity (LPC) than other vocalizations, a pattern observed but delayed in angry speech.
• High trait anxiety correlated with heightened early sensitivity to vocal emotions, particularly vocalizations.

Conclusions:

• Vocalizations, as evolutionarily primitive signals, receive neurophysiological precedence over speech-embedded emotions.
• The human brain processes vocal emotional cues earlier and more robustly than speech-based emotional cues.
• Individual differences in anxiety levels modulate the early neural sensitivity to vocal emotional expressions.