PARENTS LYING ON THE FLOOR SCREAMING ABOUT A SILLY SONG MIGHT HAVE A DIFFERENT BASIS TO IT THAN SOME OF THAT MORE POLITE SOCIAL LAUGHTER THAT YOU ENCOUNTER WHICH ISN'T HORRIBLE LAUGHTER BUT IT'S BEHAVIOR SOMEBODY IS DOING AS PART OF THEIR COMMUNICATIVE ACT TO YOU PART OF THEIR INTERACTION WITH YOU THEY ARE CHOOSING TO