Motivation - a general term for a group of phenomena that affect the nature, strength, or persistence of an. What is motivation: we are motivated to perform a behaviour to gain a reinforcer or to avoid a punisher. Experiences that we really want to repeat are those that increase, rather than decrease our level of arousal. Electrical stimulation of parts of the brain can reinforce an animal"s behaviour. Electrical stimulation of the brain is reinforcing because it activates the same system that is activated by natural reinforcers & by drugs that people commonly abuse. Function is to strengthen the connections between neurons that detect discriminative stimulus and the neurons that produce operant response. Too little arousal in the suboptimal range: leads to ineffective behaviour because the person is not sufficiently motivated. Too much arousal outside optimal range: leads to disorganized & ineffective behaviour. If behaviour is previously reinforced every time it occurred, extinction is very rapid.