Apparently, having a reasonable level of depends on early, close relations with other people.

Apparently, having a reasonable level of "intelligence" depends on early, close relations with other people.

Intelligence can be defined in many ways, simply it is the capacity of logic, emotions, interactions and understanding etc. of various issues. Having a close relation wit other people on early levels can help this capacity to enhance and progress in positive ways. 

Because he is a selfish dude

Is this form a story we need more information