Left-Side Bias: Brain Prefers Positive Sounds from Left Hemisphere

Positive human vocalizations, like laughter, coming from the listener’s left side trigger stronger activity in the brain’s auditory cortex. Researchers used functional magnetic resonance imaging (fMRI) to monitor the brain’s response to different types of sounds from varying directions in right-handed participants. They observed the highest activation in the primary auditory cortex when participants listened to positive vocalizations coming from the left, compared to front or right. This finding may imply that the nature, emotional valence, and spatial origin of a sound are initially processed in the primary auditory cortex.