My child seems to laugh without any reason. Why is that and can the protocol fix it?

Many children I work with go through a phase of short (5-15 min.) bouts of laughter without any provocation. Sometimes they will also have brief episodes of being sad and/or crying for a few minutes as well. Both of these will vanish as quickly as they appear. I had some parents refer to this as the “Drunken Sailor.” I name they conjured up since the behavior reminded them of a seafaring caricature from old movies.nThis generally resolves within a few months without any additional specific actions. Why this happens is unknown.