Effects of deprivation and reinforcement-magnitude on response variability

Animals were trained to displace any one of five response keys in order to put themselves in a stimulus condition in which reinforcement could be obtained by depressing a response lever. Decreased deprivation and magnitude of reinforcement were found to increase the variability of the distribution of key responses. The relevance of these findings to other experiments in which deprivation, reinforcement magnitude, and intermittent reinforcement were studied is discussed.     

Simulation of human problem-solving behavior

In the simulation of human behavior on a digital computer, one first attempts to discover the manner in which subjects (Ss) internally represent the environment and the rules that they employ for acting upon this representation. The interaction between the rules and the environmental representation over a period of time constitutes a set of processes. Processes can be expressed as flow charts which, in turn, are stated formally in terms of a computer program. The program serves as a theory which is tested by executing the program on a computer and comparing the machine's performance with S's behavior.     

AN INVESTIGATION OF VELOCITY SYNTHESIS

C ohen , R. L. An investigation of velocity synthesis. Scand. J. Psychol ., 1962, 3 , 97–111.—A short series of experiments has shown that it is possible to divide up the distribution of scores obtained from a group of subjects performing on the velocity synthesis apparatus mainly on the basis of (1) instructions and (2) eye behaviour. It was further found that the difference in scores dependent on differences in eye behaviour could be traced to the effect of the Aubert-Fleischl Paradox. An alternative to the gestalt model was suggested, viz. a signal/interference model.     

Control of schedule-induced polydipsi: type, size, and spacing of meals

Rats were given daily 1-min variable-interval sessions for several types of food delivered in various amounts per reinforcement and the concurrent, schedule-induced polydipsia was measured. Dry, solid food was neither a necessary nor sufficient condition for the development of polydipsia. Small portions of liquid Standard Monkey Diet produced polydipsia, but 45-mg dextrose or sucrose pellets did not. Within the range studied, smaller portions of both solid and liquid foods produced more drinking than larger portions per reinforcement. Two-min variable-interval sessions produced a greater polydipsic response than 1-min variable-interval, even though the number of 45-mg Noyes pellets allowed per session was held constant. Polydipsia was greatly attenuated on these schedules when the number of pellets remained constant, but were delivered two at a time. Within the ranges studied, the concurrent polydipsic response was increased by decreasing the rate of food acquisition, either by using smaller portions of food per reinforcement or by increasing the interreinforcement time.     

Changeover delay and concurrent schedules: some effects on relative performance measures

The pigeon and the rat partition total response output between both schedules of a concurrent variable-interval pair. The quantitative nature of a partition seems critically dependent on the relative rates with which the two schedules provide reinforcements for responding, in addition to the changeover delay. The manner in which the changeover delay controls the partition was studied by varying the duration of the changeover delay from 0 to 20 sec with each of two pairs of concurrent variable-interval schedules, viz., Conc VI 1.5-min VI 1.5-min and Conc VI 1-min VI 3-min. Rats served as the subjects and brain stimulation was employed as the reinforcer. When the schedules were Conc VI 1.5-min VI 1.5-min, relative response rate approximated 0.50 at all values of the changeover delay. When the schedules were Conc VI 1-min VI 3-min, relative response rate, computed with respect to the VI 1-min schedule, increased when the duration of the changeover delay increased. Changeover rate decreased when the duration of the changeover delay increased. The decrease was the same for both VI schedules of the Conc VI 1.5-min VI 1.5-min pair but was more rapid for the VI 3-min schedule of the Conc VI 1-min VI 3-min pair.