Humor research (also humor studies) is a multifaceted field which enters the domains of linguistics, history, and literature. Research in humor has been done to understand the psychological and physiological effects, both positive and negative, on a person or groups of people. Research in humor has revealed many different theories of humor and many different kinds of humor including their functions and effects personally, in relationships, and in society.
Cognitive neuroscience has provided insight into how humor is neurologically realized. Brain imaging techniques such as fMRI and PET scans have been implemented in this subfield of humor research.
There are a few main regions of the human brain associated with humor and laughter. The production of laughter involves two primary brain pathways, one for involuntary and one for voluntary laughter (i.e., Duchenne and non-Duchenne laughter). Involuntary laughter is usually emotionally driven and includes key emotional brain areas such as the amygdala, thalamic areas, and the brainstem. Voluntary laughter, however, begins in the premotor opercular area in the temporal lobe and moves to the motor cortex and pyramidal tract before moving to the brainstem. Wild et al. (2003)
[2] propose that the generation of laughter is mostly influenced by neural pathways that go from the premotor and motor cortex to the ventral side of the brainstem through the cerebral peduncles. It is also suggested that real laughter is not produced from the motor cortex, but that the normal inhibition of cortical frontal areas stops during laughter.
When the electrical activity of the brain is measured during and after hearing a joke, a prominent response can be seen approximately 300ms after the punchline, followed by a depolarization about 100ms later. The fact that humor response occurs in two separate waves of activity supports the idea that humor processing occurs in two stages.
Functional MRI and PET studies further illuminate which parts of the brain are participating in the experience of humor. A study by Ozawa et al. (2000) found that when participants heard sentences that they rated as humorous, the Broca’s area and the middle frontal gyrus were activated. Additionally, Wernicke’s area and the transverse temporal gyri were activated, but these areas were also found to be active in control (non-humorous) conditions.[3]