Editing Operant conditioning (section)

====Factors that alter the effectiveness of reinforcement and punishment====
The effectiveness of reinforcement and punishment can be changed. 
# '''Satiation/Deprivation''': The effectiveness of a positive or "appetitive" stimulus will be reduced if the individual has received enough of that stimulus to satisfy his/her appetite. The opposite effect will occur if the individual becomes deprived of that stimulus: the effectiveness of a consequence will then increase. A subject with a full stomach wouldn't feel as motivated as a hungry one.<ref name = Miltenberger84>Miltenberger, R. G. "Behavioral Modification: Principles and Procedures". [[Thomson/Wadsworth]], 2008. p. 84.</ref>
# '''Immediacy''': An immediate consequence is more effective than a delayed one. If one gives a dog a treat for sitting within five seconds, the dog will learn faster than if the treat is given after thirty seconds.<ref>Miltenberger, R. G. "Behavioral Modification: Principles and Procedures". [[Thomson/Wadsworth]], 2008. p. 86.</ref>
# '''Contingency''': To be most effective, reinforcement should occur consistently after responses and not at other times. Learning may be slower if reinforcement is intermittent, that is, following only some instances of the same response. Responses reinforced intermittently are usually slower to extinguish than are responses that have always been reinforced.<ref name = Miltenberger84/>
# '''Size''': The size, or amount, of a stimulus often affects its potency as a reinforcer. Humans and animals engage in cost-benefit analysis. If a lever press brings ten food pellets, lever pressing may be learned more rapidly than if a press brings only one pellet.   A pile of quarters from a slot machine may keep a gambler pulling the lever longer than a single quarter.

Most of these factors serve biological functions.  For example, the process of satiation helps the organism maintain a stable internal environment ([[homeostasis]]). When an organism has been deprived of sugar, for example, the taste of sugar is an effective reinforcer. When the organism's [[blood sugar]] reaches or exceeds an optimum level the taste of sugar becomes less effective or even aversive.