The social life of laughter

Abstract

Laughter is often considered to be the product of humour. However, laughter is a social emotion, occurring most often in interactions, where it is associated with bonding, agreement, affection, and emotional regulation. Laughter is underpinned by complex neural systems, allowing it to be used flexibly. In humans and chimpanzees, social (voluntary) laughter is distinctly different from evoked (involuntary) laughter, a distinction which is also seen in brain imaging studies of laughter.

Keywords: conversation; emotion; laughter; motor control; voice.

Figure 1. Voluntary and involuntary laughter in the brain

The coordination of human laughter involves periaqueductal gray and the reticular formation with inputs from cortex, the basal ganglia and the hypothalamus [10]. The hypothalamus is more active during reactive laughter than voluntary laughter [11]. Motor and premotor cortices are involved in the inhibition of the brainstem laughter centres, and are more active when suppressing laughter than when producing it [11]. Laughter perception involves premotor cortex and SMA [12], while auditory and mentalizing regions showed differential engagement by involuntary and voluntary laughter [13].