Laughter genuinely happens during sleep, so part of this needs no symbol at all. Where tradition does read it, everything turns on who else was laughing.
Laughter genuinely happens in sleep. People wake themselves up laughing, partners report it, and it has been recorded often enough that the sound itself needs no symbolic explanation. Where dream tradition does read the image, it treats laughter as release, and it pays close attention to whether the dreamer was laughing alongside people or being laughed at, because those two dreams have almost nothing in common.
Shared laughter is one of the few images the old books discuss without hedging. It is generally read as ease, belonging and pressure coming off, and dreamers frequently wake from it in better spirits than they went to sleep in. Being laughed at is handled quite differently and has long been tied to exposure, to the fear of appearing foolish in front of people whose opinion carries weight. The room, the faces and whether the dreamer knew them tend to matter more than the joke, which is nearly always forgotten by morning.
A good many people report laughing at something that was not funny, or finding they could not stop. Interpreters have connected uncontrollable laughter to feeling emotionally out of step with a situation, the sort of nervous response that surfaces at funerals and in hospital corridors. Laughter in a setting where it clearly does not belong is read along the same lines. There is nothing ominous in either version. Sleep mixes its signals routinely, and a mismatch between what is happening and what the dreamer feels is among the ordinary things dreams do.
None of this promises good news, and the old claim that laughter in dreams foretells its opposite is superstition rather than reading. What the image can do is register something about the week behind it. Somebody who laughs easily awake brings a different weight to this dream than a person for whom laughter has usually meant being the target, and that private history deserves more trust than any general meaning.


