Imagine that you are a space alien and you are studying humans. So through years of study, you note that humans seem to have a relatively high bandwidth channel of communication. By an extraordinarily rapid and precise use of their larynx and their vocal cords. They move their tongue and their lips very rapidly. They blow air at just the right moments. And in this way they have language. They communicate to each other at about 39 bits per second, which is a pretty good transmission rate and way higher than any other animal species, as far as you, the alien, can tell. But there’s something else. These human creatures do something that’s very strange. Every once in a while, they do a much lower frequency, lower bandwidth thing where they make a series of rhythmic, involuntary contractions of their diaphragm. Which causes a sequence of vocalized exhalations, usually a series of short, repeated vowel sounds like ha or he or ho. Now, you notice that this typically begins with some language or event that triggers the brain’s reward centers and lights up something about the emotional networks. And that triggers the activation of facial muscles, particularly around the mouth and eyes. And often the human’s mouth will open up wide, and the corners of the lips will get drawn back and upward. And the respiratory starts doing these rapid cycles of inhalation and exhalation, which throws a wrench in the normal breathing patterns. And the heart rate increases and The blood pressure rises and the eyes might start to produce tears. And the skin around the face might start turning red because of the increased blood flow. Sometimes the whole body shakes or quivers, especially in the shoulders and torso. And this physical manifestation, this can spread to the limbs, leading to movements like clapping or slapping or bending over. Now, the question you ask as the alien is, why do they do this strange laughing thing? Is there an evolutionary reason behind it