The average 4-year-old laughs 300 times per day, whereas the average 40-year-old laughs four times per day. A study done in 1999 revealed the average adult laughed 17 times per day when participants were asked to record how many times they laughed in three days.
Laugh expert Robert Provine, who has studied laughter for 30 years, explains the average adult laughs around 20 times per day. A German study conducted in 2004 indicates a single bout of laughter, meaning a laugh that occurs in a single exhalation, occurs an average of 5.8 times in a 10-minute period during normal conversations. Speakers in a conversation laugh more often after their own sentence rather than someone else's sentence.