Submitted by David1192 t3_10inpk1 in explainlikeimfive
If a person were to be in a situation where they had no human contact from the time that they are still small, would things like smiling and laughing come naturally to them, or is it all learned behaviour?
Remarkable-Owl2034 t1_j5fbyux wrote
Babies smile, laugh and cry without being taught. It seems likely that these reactions are inborn and universal.