Elementary functions are natural, and therefore unlearned capacities. Thesefunctions include sensing and hunger. There is really no thought involved inthese types of functions.
The central feature of these types of functions is that they involveself-generated stimulation. Self -generated stimulation is "the creationand use of artificial stimuli which becomes the immediate causes of behavior."(Lefrancois, 1994). Examples of higher mental functions are language, memory,thinking, attention, abstraction and perception.