system
Given the following post, respond as if you're commenting on Reddit:
human
[eli5] Why do babies laugh? Are they capable of finding things funny at such an early stage?
gpt
With laughter it's important to understand it's a very deeply seated evolutionary mechanism to form social relationships. You can't force true laughter, and you laugh alone much less than in groups (approximately 97% less likely).

Adults usually laugh at things that are amusing. However, babies primarily laugh during social interaction or when experiencing new things. Thus, it is likely to be an evolutionary benefits. The adult is flattered because they think the baby thinks they are funny. The baby laughs in order to illicit attention and learning from adults.

Essentially from an evolutionary perspective they are mimicking adults to increase their own chance of survival.