An apparatus for apparent conditioning ofOctopus cyaneus Gray

An ann-out-of-water response was conditioned as an operant inOctopus cyaneus Gray. The response was limited to a vertical tube, 2.54 em i.d, Photoresistive sensors, illuminated with modulated light arranged around the tube above the waterline, detect the presence of an opaque object in the tube. The signal from this response detector is amplified and used to initiate a commercial motor-driven universal feeder according to the reinforcement schedule maintained by the logic control circuit. A sample cumulative record for perfonnance on a CRF schedule is given.     

Some effects of frustration in a free responding operant situation

In several experiments, rats and pigeons were reinforced on a chained schedule which varied in its second component but which always had a variable interval schedule as its first component. Occasionally, the reward which normally followed responding in the second component was omitted. On these frustrative non-reward occasions responding immediately subsequent to non-reward was sometimes elevated and sometimes depressed. The relevance of the elevation and depression effects to behavioural measures of frustration in the double runway was discussed.     

Context Conditioning and Free operant Acquisition under Delayed Reinforcement

Three experiments examined the effect of context conditioning on the acquisition of freeoperant lever pressing by hungry rats when the presentation of the food reinforcer was delayed for 32 sec. The first study replicated the preexposure effect reported by Dickinson, Watt, and Griffiths (1992): Exposure to the contextual cues with the lever withdrawn prior to each instrumental training session enhanced acquisition, an effect that was attenuated by the presentation of non-contingent reinforcement during the preexposure periods. Signalling the non-contingent reinforcers during the preexposure periods with a brief auditory stimulus enhanced acquisition in a second study, suggesting that the non-contingent reinforcement interferes with acquisition through context conditioning. The final study confirmed this conclusion using a within-subject procedure in which pressing different levers was reinforced in two contexts, one of which was also associated with non-contingent reinforcers.     

Drive level and cue utilization in a free operant situation with albino rats

Summary Albino rats under either a daily high (2 gms) or moderate (12 gms) food deprivation condition were presented stimuli at the termination of reinforced fixed ratio bar press response chains. Within each drive group, half the animals received a session of brief light-off stimuli accompanied by reinforcement followed by a session of a buzzer and light-off compound stimuli paired with reinforcement. The remaining animals had the buzzer first paired with reinforcement and then the compound stimulus paired with reinforcement. Each stimulus element was tested for its respective control of nonreinforced food-cup approach behavior. These tests demonstrated that the buzzer cue blocked and overshadowed control of approach behavior of the light-off cue. In animals that received the initial light-off conditioning session, overshadowing by the buzzer of the light-off stimulus was less strong in high than moderate drive animals. These results were discussed in terms of Kamin's (1969) findings and Easterbrook's (1959) arousal-cue utilization hypothesis.The present study was supported by a grant given to the senior author from the National Research Council of Canada (APA 7450). The findings of the single stimulus control groups were also presented as a paper in modified form to the Canadian Psychological Association at its annual meeting, 1974, Windsor, Ontario, Canada.     

Signal duration and suppression of operant responding by free reinforcement

Pigeons were trained on a VI (variable interval) schedule of food presentation with a superimposed schedule of response-independent food. Substantial suppression of the operant response rate occurred when the free food was presented without a signal. When the free food was preceded by a short (4 sec) signal, the degree of suppression was similar to that with unsignaled free food. But when the signal was lengthened to 12 sec, the degree of suppression was substantially reduced. Experiment 3 assessed the effect of signal duration using a baseline schedule of delayed reinforcement, in which contingent reinforcers were themselves preceded by a signal. The signal preceding the free reinforcers was then either the same as or different from this contingent signal. Signal duration effects occurred only when the two types of signals were different. These differences as a function of signal duration have implications for both “context-blocking” and “comparator” interpretations of the effects of noncontingent reinforcement in both Pavlovian and operant procedures.     

Two temporal parameters of free operant discriminated avoidance in the rhesus monkey

Four monkeys were exposed to free operant discriminated avoidance (discriminated Sidman avoidance) in a parametric study of safe stimulus and warning stimulus duration. The safe stimulus was assigned values of 2, 5, 10, 20, and 40 sec, the warning stimulus values of 2, 5, and 20 sec. Rate of responding was a decreasing negatively accelerated function of safe stimulus duration, with a small effect attributable to warning stimulus duration. Control of response rate by safe stimulus duration was due to the predominance of responding in the presence of the warning stimulus. Responding during the safe stimulus was independent of the temporal parameters except at schedules combining short safe and short warning stimulus durations. Latencies of responses in the warning stimulus were analyzed, and mean latency was found to be a direct function of warning stimulus duration, with only one exception, resulting from the order in which the warning stimulus values were presented. Shock rate was not systematically related to either of the manipulated parameters.     

Measures of observer agreement when binomial data are collected in free operant situations

This paper examines a model and defines reasonable assumptions underlying different measures of observer agreement for categorical data collected in free operant situations. It is assumed that two or more observers classify operant behaviors of subjects into occurrences and nonoccurrences by recognition by validated response classes (categories) such that the rates of false positives and observer biases are acceptably low. Thus errors are mostly omissions, i.e., failing to observe events that occur. Four alternative cases are derived, together with formulas for calculating significance tests, variances, and standard errors, three of which do not depend on knowledge of the proportion of time points at which the event does not occur.We wish to acknowledge NICHD Grant HD-10570, The Neuropharmacology of Developmental Disorders, George Breese, Ph.D., and C. T. Gualtieri, M.D., Principal Investigators; NIEHS Grant ES-01104; USPHS Grant HD-03110; and MCH Project 916 to the Division for Disorders of Development and Learning.     

d-Amphetamine-chlorpromazine antagonism in a food reinforced operant

Dose effect curves for d-amphetamine and chlorpromazine were obtained with rats on a milk reinforced FR 10 schedule. A dose of d-amphetamine (2.5 mg/kg, i.p.) which completely suppressed all responding for 60 min was administered simultaneously (concomitant with the pretreatment times) with various doses of chlorpromazine. The d-amphetamine-induced cessation of responding was removed by several of the doses of chlorpromazine with maximal antagonism occurring at a dose of 1.5 mg/kg i.p. This dose of chlorpromazine, when administered independently, produced no observable side effects and showed no effect on the FR 10 schedule. One animal appeared to develop tolerance to the repeated dosages of d-amphetamine.     

Design decisions in a Pascal-based operant conditioning system

FREDL, a Pascal-based system for control of operant experiments, has been implemented on the IBM PC computer. In the foreground, recurring operations, such as decrementing counters that serve as local clocks, are controlled by a dictionary specifying automatic properties of user defined variables, and random logic is implemented by a user-written Pascal overlay. In the background, the remainder of the program controls communication with the user, output of data to disk, and production of cumulative records.     

Overshadowing in operant conditioning as a function of discriminability

Pigeons were trained in an operant, go/no-go, discrimination by successive presentations of discrete, positive and negative trials. In separate groups, the rate of discriminaion learning based on an auditory cue, on visual cues of different discriminability, and on combined auditory and visual cues was determined. The auditory cue was tone/no-tone, the visual cue was a difference in brightness level on the key. Following discrimination training, stimulus control was tested in extinction by presenting tone or notone at each of four key-brightness levels.Learning was more rapid with two cues than with either cue singly, demonstrating summation. The contribution made by the tone cue to the learning of the discrimination decreased with increasing discriminability of the light cue. The control exerted by the tone cue also decreased (i.e., the tone cue was overshadowed) with increasing discriminability of the light cue. In certain cases, the tone cue decreased control by brightness, showing that in two-cue discriminations each cue may reduce the control exerted by the other.