Group-laugh is the equivalent for laughter of group-think. We can draw a rather wide 3x3 table which points to obvious distinctions when one has experienced them:
Thinking can be individual, done in small groups, or devolve into group-think, which is dogmatic and so contains next to thinking, instead referring to beliefs rigidly assumed to be true
Art can be done by individuals, small scenes (scenius) or by a committee, which has no artistic integrity and merely chases profits by appealing to the lowest common denominator
Finally, laughter can be genuine, coming from an individual or the entire group, or it can be group-laugh, where one isn't really laughing but rather fawning to meet an expectation of what the others would laugh at. This is the mechanism used by laughing tracks
In those 3 scenarios, the last category maps to a collective which maintains the illusion of consensus by utterly destroying real individuality and the quality which arises from it, whereas the middle is an example of a healthy collective, one which inevitably must be rather small and localized, otherwise the demands of the large collective outweigh the sensitivities and intelligence of the individuals, the same way that bureaucracy has no need for human discernment, and crushes it under the demands of its own tautological need of maintaining the bureaucracy at all costs.
Group-laugh is laced with anxiety, a nervousness where one is examining whether the others also find it funny, because ultimately the laugh isn't felt from within, but rather mechanically caused from the outside, which is why it is so fake, the same way that porn is a simulacrum of real sexual intimacy, and instead bombards you shallow excitement.
Ultimately group-laugh is what deeply unhappy collectives do, because they have no access to real joy which requires a sort of surrender to life and the present moment. Which is probably why irony and cynicism are such common ways to trigger a group-laugh, because those are additional layers of armoring from dealing with reality as it is.