A well meaning aunt talked with her 9-month old nephew about meeting her new boyfriend. However, when he saw the young man, the child shrieked inconsolably. "It must be the mustache!" the aunt thought. What do you think Piaget would have to say about this assessment?

Piaget spoke about the different stages of cognitive development by which cognitive operations are to be expected in certain age.

Piaget wouldn't have agreed that the problem was the mustache, but the fact that a 9 month baby is still in a process of develpment. An for instance asimiliation and acomodation, processes to accept and understand a new object, such as a strager probably haven't developed yet.

Explanation:

A 9 year old baby according to Piaget, is going through a stage called sensory-motor. In this stage a baby could have developed the notion of a permanent objetc, this is how he can recognize people that are close to thim. For this reason he or other babies at that age, can get scared with new people, since they already identify familiar objects.

By the other hand asmiliation and acomodation are cognitive processes that allow a person to accomodate and accept unfamiliar objects, and integrate them to their mental processes. This baby may still be in the way of constructing these important processes. So his reaction is to be expect.