Semiotic aspects of human nonverbal vocalizations: a functional imaging study

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Humans produce diverse nonverbal vocalizations, including affective bursts (e.g., laughter) with social roles and vegetative sounds (e.g., snoring) indicating physiological states.
• Some vegetative sounds, like belching, can function as intentional vocal gestures with arbitrary, culture-dependent meanings, similar to spoken words.

Purpose of the Study:

• To investigate the neural processing of different types of human nonverbal vocalizations.
• To differentiate brain responses to affective vocalizations, vegetative sounds, and intentional vocal gestures.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure hemodynamic responses.
• Participants performed a decision task involving exposure to affective bursts, vegetative sounds, and vocal gestures.

Main Results:

• Affective bursts activated the anterior left superior temporal gyrus.
• Arbitrary vocal gestures, interpreted as intentional, elicited hemodynamic responses in the left temporo-parietal junction.
• These findings suggest a distinct neural pathway for processing intentional nonverbal vocalizations.

Conclusions:

• The brain distinguishes between involuntary and intentional nonverbal vocalizations.
• A left-hemisphere temporo-parietal 'auditory-to-meaning interface' may be crucial for interpreting vocal gestures as intentional communicative acts.
• This interface appears linked to the brain's speech processing mechanisms.