ABSTRACT
The list of major variables influencing control learning is similar to that for predictive learning:
• Deprivation • Timing of consequence • Intensity of consequence • Scheduling of consequences • Contingency between response and consequence
Deprivation
In order for appetitive stimuli to be most effective, the individual usually must have experienced recent deprivation. The simplest procedure to accomplish this is to manipulate the amount of time since the individual consumed the stimulus (e.g., food, water). A complicated but more sensitive procedure is to maintain the individual at a percentage of the weight it reaches when provided free access to the stimulus. For example, if a rat’s free-feeding body-weight is 500 grams and it was to be kept at 80% of this weight, its food intake would be reduced until it reached 400 grams. Please recognize that the U.S. government and the American Psychological Association have strict ethical guidelines for conducting research with nonhuman subjects. These guidelines apply to deprivation procedures as well as those involving aversive stimuli. Laboratory animals typically have much safer and comfortable environments than those living in the wild. For example, rats and pigeons do not have free access to food in nature and are usually in a state of mild, if not severe deprivation most of the time. The level of deprivation maintained in the lab is typically low, just enough to ensure that the animal will work for the substance.
