playful attitude

[bosun]

Can you please explain what the red words mean in the following sentence?

1. Laugh and the smile are often mentioned in the same breath. Yet they are used quitely differenly in primate displays with the smile expressing affection and appeasement rather than playfulness.

2.It is obvious that his research not only opens new avenue into human social life but also carries mental implication.

[Tdol]

A smile can have a serious purpose; to calm things down, while laughter is more readily associated with having fun.

I'm not too sure about the second, but it could mean that it affects these two areas- the external social life and the interior mental one.