You and your brother are babysitting your infant cousin. Initially, he is very interested in a puppet that you were using, but seems to not be very interested in it after a few minutes. Your brother thinks that he might not have a very long attention span. You tell your brother that your cousin is actually displaying

habituation

Explanation: In psychological learning habituation could also be seen as the process where there's a reduction in response to a stimulus after being repeatedly exposed to it. This process states that an animal or a person's may learn to ignore a stimulus due to repeated exposure to it.

Habituation

Explanation:

Is proclaimed to be a form of implicit learning.  with continually repeated stimuli.    Is consistent with the definition of habituation as a procedure.

In a plain definition, is the process of people or animals becoming used to something, gradual adaptation to a stimulus or the enviroments.  

permafrost layer, it exists beneath a layer of soil, rock or sediment.

answer; recognition and measurement;