Hugh enjoys playing with your keys. when you take them away and place them in your pocket, hugh does not search for them. piaget would say that hugh does not understand:

Object Performance. This hypothesis was given by the Swedish researcher Jean Piaget and it is of the understanding that items keep on existing notwithstanding when they can't be watched (seen, heard, touched, noticed or detected in any capacity). The theory is a leap forward in the study of the brain as it relates to little children and how they react to certain situations that puts their mental ability to a stretch. The researcher is of the idea that kid's reason and how that take things around them depends on their motor development which is what Hugh needed to keep on searching for the keys.