Laurence H. Berger

Wheel-running in discrete trial and operant paradigms under various effort requirements

Two experiments were conducted in which the wheel-running behavior of rats under various effort requirements was investigated. The specific effort requirements were obtained by varying the tangential force required to initiate wheel movement. In the first experiment, a discrete trial preparation was used in which 4 groups of rats received training with high effort levels of 90, 110, 130, and 150 g. The results showed that increasing effort requirements slowed the rate of acquisition, lowered the asymptotic running speeds, and reduced resistance to extinction. In the second experiment, using an operant preparation, running speeds were examined for baseline (nonreinforced) and fixed-interval 1 min schedules of reinforcement at effort levels of 45, 90, and 180 g. The results clearly showed wheel-running to be schedule-induced. However, the effects of effort on FI behavior were less clear due to inconsistencies between subjects. Results are discussed in terms of the potential benefits of bridging operant and discrete trial preparations and methods for studying the effects of effort on animal behavior.

A simple and sensitive method for monitoring running-wheel movement

A running-wheel movement-detection method is described for use with a modified 1350 Commodore mouse and a Commodore 64, is described. The movement-detection method allows for the detection of partial revolutions and direction of movement, but requires no interface equipment. The modified running wheel is discussed as a new technique that may be useful for bridging empirical and theoretical differences between free-operant and discrete-trial runway procedures.

Bilateral nictitating membrane conditioning in rabbits under asymmetrical levels of cutaneous afferent activity

Abstract The effect of asymmetrical levels of cutaneous afferent activity (CAA) on the performance of a bilaterally conditioned nictitating membrane response in New Zealand albino rabbits was investigated. Afferent activity levels were controlled by varying US locus, corneal applications of a local anesthetic (0.5% tetracaine hydrochloride) and by exerting mechanical tension on the eyelids. Performance of the response in each eye was controlled independently of the response levels concurrently attained by the contralateral eye. Appropriate tests suggested that the two eyes do not function independently in learning, regardless of the disparity in CAA level between them, due to central transfer.

Extinction in rabbits under different levels of cutaneous afferent activity

Abstract The nictitating membrane response of the rabbit was classically conditioned to tone, using a shock US, under a moderate level of cutaneous afferent activity (CAA). The CAA was controlled by mechanical, chemical and electrical means. In Experiment 1 the response in three groups of animals was extinguished under different levels of CAA. High levels were found to retard and low levels facilitate the disappearance of CRs during extinction. In Experiment 2 the possibility was investigated that one of the means used to raise CAA (e.g., the eyeband) might have produced a high spontaneous response rate. A 6% response level was observed but: (1) was of short duration; (2) was too small to account for group differences in the first experiment; and, (3) was not a significant factor in the statistical analysis of Experiment 1.

The effects of real and dark light on single unit activity in Macaca mulata.

Abstract The activity of single units in the lateral geniculate nucleus in the rhesus monkey was monitored. Activity produced by the process of bleaching photopigment molecules (field adaptation) was found to have effects on the sensitivity of these units similar to the effects produced by previously bleached molecules (bleaching adaptation), but the effects on maintained firing rate were different. Thus, the unit activity was consistent with the equivalent background principle of visual adaptation, but not with the equivalent luminance principle. It was also found that unit response characteristics to an increment of stimulus intensity could be changed from “off” to “on” in bleaching adaptation conditions, but not in field adaptation conditions. This suggests differential effects on receptive field organization characteristics.

Effects of Contralateral Cutaneous Afferent Activity on Acquisition of a Nictitating Membrane Response

The effects of 2 different levels of contralateral cutaneous afferent activity on acquisition of the nictitating membrane response in 2 groups of rabbits was examined. Differences in the level of contralateral afferent activity from the primary response area were found to have no statistically significant effect on the acquisition rates of an ipsilaterally developed nictitating membrane response.

The Interactive Schedule: A Common Conceptualization for Ratio and Interval Schedules

A new mathematical method for specifying response-time-reinforcement contingencies is presented and called the interactive schedule. It allows the experimenter to specify schedule of reinforcement characteristics along a single continuous dimension, x. Ratio schedules are specified at one point of the continuum (x = 1) and interval schedules are specified at another point (x = 0). At all other values of x the specified interactive schedule requirements are a“blend” of ratio and interval schedule requirements, in which both the rate of reinforcement and the number of responses per reinforcer are dependent variables related to the rate of responding. The behavior of rats was observed with interactive schedules having four values for x between zero and unity inclusively. When x is greater than zero and less than unity a trade-off is specified in which an increase in the rate of responding increases the rate of reinforcement, but at a cost of increasing the number of responses per reinforcer required. Subjects responded at higher rates for values of x closer to unity (more ratio-like) and at lower rates for values of x closer to zero (more interval-like). Response rates were not proportional to reinforcement rates, nor did subject maximize the rate of reinforcement. Classes of models of behavior are discussed, and it is suggested that two-dimensional economic models which have as factors both reinforcement and response cost are most consistent with these data. It is further suggested that the interactive schedule may be a useful experimental tool in assessing such two-dimensional models because it can specify two-dimensional relationships between the dependent variables of reinforcement rate and response cost (number of responses per reinforcer) as functions of the rate of responding.

The effect of cutaneous afferent activity on instrumental learning in rabbits.

Abstract The nictitating membrane response was trained in rabbits by two methods: (a) an instrumental escape-avoidance paradigm, and (b) a yoked classical conditioning paradigm. The magnitude of cutaneous afferent activity (CAA) from the orbital region of the eye was controlled using mechanical and chemical means. Animals received training in both instrumental and classical conditions with augmented and diminished CAA. Diminished levels of CAA were found to depress learning in both training paradigms. Instrumental animals emitted more nictitating membrane responses than did the yoked classical controls under conditions of augmented CAA. It was concluded that the general importance of the role of CAA in learning was strengthened.

A balance panel, amplifier, and trigger device for nictitating membrane transducers

Description and circuit are provided for a balance panel, amplifier, and trigger device for nictitating membrane devices.

A Self-Environmental Systems Model and Its Implications for Behavior Change

Psychologists who are interested in basic research and psychologists who are interested in applied research often do not communicate well; they often talk at one another rather than with one another. Such a tendency is particularly unfortunate in the field of psychology. For example, “rat runners” and “behavior therapists” have a great deal to offer one another, precisely because of their different perspectives on the same general subject matter. If the two branches of psychology were to get “divorced” on the grounds of irreconcilable differences, it would surely be the case that the applied branch would have to develop a basic science capability, for effective application is based on scientific discovery. In a similar vein, the basic science branch would have to develop an applied capability, because basic science without application is sterile and wasteful. It would be a shame to go through all that work and conflict just to end up in the same places.