In E.T.: the Extra-Terrestrial, the titular character acts pretty immaturely at times.
For example, he
follows a random, obviously planted candy trail, on a hostile planet,
drinks alcohol without understanding the repercussions,
and gets super-emotionally invested in a movie, to the point of subconsciously using a psychic link to get someone to recreate a scene from it.
Canonically, was he young or immature, or was he just a member of a fairly naïve species?