THE EFFECT OF CHANGING THE SCHEDULE OF REINFORCEMENT UPON DURATION OF RESPONDING¹

Abstract

A usual datum under study in free-operant research is the rate of responding (Ferster, 1957). Of course, each response may be analyzed into smaller units, or particular dimensions. Trotter (1956aTrotter ( , 1956bTrotter ( , 1957 has divided the response in a bar-pressing situation into three components: the active time when the rat is touching the bar; eating time spent in picking up and eating food; and extra time spent in washing, resting, etc. Gilbert (1958) has investigated other dimensional properties. He lists seven, and presents cogent arguments that awareness and use of such dimensions in the analysis of the response will avoid several pitfalls of uncritically combining them.The reduction of gross behavior to finer quantifiable units obviously would facilitate greater predictive value and better control over the organism's behavior. At this time, we wish to investigate the length of bar depression (hereafter called D). From existing evidence (Trotter, 1957), we would hypothesize that D is not consistently influenced by such variables as force required to depress the bar or length of deprivation.The duration of bar depression may be measured in three ways: mechanically (by coupling a moving pen with the bar), electronically (by coupling a moving electric-eye diaphragm with the pen), and electrically (by letting the bar close a microswitch). The latter method was selected because of its simplicity; but this measure will yield no record of the actual time the animal was in contact with the bar. The animal may make bar presses which are not sufficient to close the microswitch. Thus, the measure obtained will constitute only those parts of the response when the pressure applied to the bar will be at least as strong as the resistance of the combined springs of the bar and the microswitch involved.The purpose of this study is to develop a reliable method of measuring the length of depression in the bar-pressing situation, and to determine the lawfulness of this datum under varied schedules of reinforcement. APPARATUSTwo response cages with a rat lever (Stoelting, University of Chicago design) were placed in insulated cooler chests to eliminate outside lighting and noise disturbances. Except for the translucent plastic front, the cage is made of heavy-gauge sheet aluminum. The substrate consists of stainless-steel rods spaced to pass animal waste freely. The stainlesssteel lever is sprung, and protrudes 2 centimeters from the rear wall, 8.5 centimeters above the grid floor and 5.5 centimeters off the right wall. The bar is 5.5 centimeters wide and center-mounted horizontally to the lever; it travels approximately 0.4 centimeter when depressed; an 18-gram downward force upon the bar is required to activate the microswitch.The reward lever is activated by an impulse such that it dips down and returns (by means of a counterweight) when the impulse ceases, but not before an interrupter switch has been activated at the lowest point of the reward lever. This interrupter switch serves to bring the reward lever to its l...

INFLUENCE OF REINFORCEMENT SCHEDULES ON RESPONSE DURATION1

“…2) appear more in the nature of gentle trends over the entire Fl series than as abrupt changes correlated with each schedule shift, as has been reported to occur under FR manipulation (Schaefer & Steinhorst, 1959). This gradual shift in durations might well be due principally to extended exposure under intermittent-reinforcement procedures and be independent of the changes made in the Fl.…”

“…The correlation is not perfect, however, and the changes in rate cannot be wholly explained by the duration fluctuations. atively low mean and variance, like the CRF functions (cf., also, Schaefer & Steinhorst, 1959); but they lack the symmetry of the distributions associated with CRF. Figure 8 shows distributions of durations of all three rats on Day 15.…”

RESPONSE LATENCY AS A FUNCTION OF REINFORCEMENT SCHEDULE1

“…An experiment by Schaefer and Steinhorst (1959) indicates the possibility of a similar relation for response duration. Rats shifted from CRF to a fixedratio schedule showed significant increases in response duration.…”

Methods and Findings in an Analysis of a Vocal Operant

“…An analysis of response amplitude, pitch, and duration showed that the mean and variance of these parameters typically increase from CRF to VI, from VI to EXT and, for a second group of Ss, from CRF to EXT. The topography of the chick's vocal response appears to stand in the same relation to reinforcement operations as does the human vocal response.Lately, there has been a considerable increase in research in two heretofore unrelated areas: the rate of emission of vocal operants (Flanagan, Goldiamond and Azrin, 1958;Lane, 1960Lane, , 1961 Shearn, Sprague and Rosenzweig, 1961;Starkweather, 1960; Starkweather and Langsley, 1961) and the topographical properties of non-vocal behavior (Goldberg, 1959;Margulies, 1961;Millenson, Hurwitz and Nixon, 1961; Notterman, 1959;Schaefer and Steinhorst, 1959 There is a certain irony, therefore, in observing that the vocal response may be pre- …”

“…Lately, there has been a considerable increase in research in two heretofore unrelated areas: the rate of emission of vocal operants (Flanagan, Goldiamond and Azrin, 1958;Lane, 1960Lane, , 1961Shearn, Sprague and Rosenzweig, 1961;Starkweather, 1960;Starkweather and Langsley, 1961) and the topographical properties of non-vocal behavior (Goldberg, 1959; Margulies, 1961;Millenson, Hurwitz and Nixon, 1961;Notterman, 1959;Schaefer and Steinhorst, 1959 'Also note papers presented at (1) Symposium on the Control of Verbal Behavior, Amer. Assn.…”