Experts from Perm Polytechnic University theorize that laughter initially emerged in our ancient ancestors as a response to tickling during play, signaling that the interaction was safe. Subsequently, as pschological complexity increased, social cues alone began to trigger laughter without physical contact, yet the physical manifestations—muscle spasms and breathing patterns—have persisted, continuing to confirm the safety of the exchange.
Valery Litvinov, Candidate of Medical Sciences and Senior Researcher at the “Chemistry and Biotechnology” Department of PNIPU, points out that laughter is observed in higher primates, rats, and dolphins, where in animals it denotes a playful mood and the absence of aggression.
Contagiousness and Socialization
Mirror neurons unconsciously compel us to mimic the emotion of someone who is laughing. The amygdala interprets their relaxed state as a cue that “there is no danger; one can join in.” Shared laughter restores a feeling of childhood security, allowing for relaxation and a sense of belonging to a collective. Furthermore, by observing others, we absorb the norms of humor, making it a tool for socialization, demonstrating group affiliation or adherence to a cultural code.
How the Brain Recognizes a Joke
Upon hearing something amusing, the amygdala processes the signal as a safe surprise that provokes delight. The cortex (temporal and frontal lobes) deciphers the meaning and connects it to the existing context. The signal then travels to the subcortical and brainstem nuclei, which initiate the contraction of the diaphragm, larynx, and facial muscles, accompanied by an increased heart rate and intermittent breathing.
According to Yulia Neverova, a Cognitive-Behavioral Psychologist and Senior Lecturer at the “Sociology and Political Science” Department of PNIPU, laughter arises as a reaction to incongruity—the brain detects a cognitive mismatch and releases an emotional catharsis. This principle underpins nearly all jokes: an unexpected resolution shatters prior expectations, and provided that mismatch poses no threat, the brain rewards this resolution with laughter.
Impact on the Body
During laughter, endorphins (which reduce pain and anxiety), dopamine (pleasure), and serotonin (mood stabilization) are released. Levels of stress hormones like cortisol and adrenaline decrease. Immune system function improves, metabolism stabilizes, and the cardiovascular system receives a workout (heart rate increases, vessels dilate, followed by relaxation), which enhances tissue elasticity and normalizes blood pressure.
Gender Differences and Dark Humor
Women tend to laugh more frequently than men, presumably due to greater emotional expressiveness. Women lean towards irony and use humor for communication, whereas men favor situational humor and use it to project status. Women also more often laugh at jokes told by men.
Conversely, a predisposition for dark humor is linked to high intelligence (as it demands complex interpretation), but it is concurrently influenced by empathy and emotional intelligence—the ability to judge when such humor is appropriate.
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