Is there a name for the phenomena of contagious laughter in scientific or physiological terms?

Question

for example laughing when you hear a baby laugh. Not a real illness

Answer 1

monty-pythonology

Answer 2

laughing sickness -kuru- appears to be something else a disease where the sufferer cannot stop  laughing - I think maybe what you are talking about could come under mass hsyteria.

Answer 3

It is usually a phenomena related to stress..I'm not aware of a specific diagnostic term..however in the absence of Cannabis, It's all about stress relief.