The Experimental Analysis of Behavior
The 1957 American Scientist article, reproduced in full
Another field in which important variables affecting behavior are studied is neurology. Performances under various schedules of reinforcement supply base lines which are as useful here as in the field of psychopharmacology. The classical pattern of research is to establish a performance containing features of interest, then to remove or damage part of the nervous system, and later to have another look at the behavior. The damaged performance shows the effect of the lesion and helps in inferring the contribution of the area to normal behavior.
The procedure is, of course, negative. Another possibility is that neurological conditions may be arranged which will have a positive effect. A step in this direction has been taken by James Olds  with his discovery that weak electrical stimulation of certain parts of the brain, through permanently implanted electrodes, has an effect similar to that of positive reinforcement. In one of Olds’ experiments, a rat presses a lever to give itself mild electrical stimulation in the anterior hypothalamus. When every response is so “reinforced,” behavior is sustained in strength for long periods of time. One of Olds’ results is shown in Figure 17. The electrical “reinforcement” was begun shortly after noon. The rat responded at approximately 2000 responses per hour throughout the day and night until the following noon. There are only three or four brief pauses during this period. When the experiment was continued the following day, however, the rat fell asleep and slept for 20 hours. Then it awoke and began again at approximately the same rate. Although there remain some puzzling differences between behavior so reinforced and behavior reinforced with food, Olds’ discovery is an important step toward our understanding of the physiological mechanisms involved in the operation of the environmental variable. A similar reinforcing effect of brain stimulation has been found in cats by Sidman, Brady, Boren, and Conrad  and in monkeys by Lilly, of the National Institutes of Health, and Brady, in the laboratories of the Walter Reed Army Institute of Research.