The effect of signaled reinforcement availability on concurrent performances in humans

During Phase I, three female human subjects pressed a button for monetary reinforcement in two-component concurrent variable-interval schedules. Five different reinforcement frequencies were used in component A, whereas the reinforcement frequency in component B was held constant. Absolute rates of responding conformed to equations proposed by Herrnstein to describe concurent performances, and the ratios of the response rates and the times spent in the two components conformed to the matching law. During Phase II, the availability of reinforcement in component A was signaled by the illumination of a lamp. This resulted in suppression of response rates in component A and elevation of response rates in component B, these changes being reflected in a distortion of the matching relationship which took the form of a bias in favor of component B.     

Effect of variable-interval punishment on the behavior of humans in variable-interval schedules of monetary reinforcement

One male and three female human subjects pressed a button for monetary reinforcement under a range of variable-interval schedules specifying different frequencies of reinforcement. On alternate days, responding was also punished (by subtraction of money) according to a variable-interval 170-second schedule. In the absence of punishment, the rate of responding was an increasing negatively accelerated function of reinforcement frequency, as predicted by Herrnstein's equation. The effect of the punishment schedule was to suppress responding under lower frequencies of reinforcement; responding under higher reinforcement frequencies was much less affected. This was reflected in an increase in the value of K_H (the constant expressing the reinforcement frequency corresponding to the half-maximal response rate), whereas there was no significant change in the value of R_max (the constant expressing the maximum response rate). Previous results had shown that variable-ratio punishment resulted in a change in the values of both constants (Bradshaw, Szabadi, and Bevan, 1977). The results of the present study were consistent with the concept that the suppressive effects of punishment on responding depend on the nature of the punishment schedule.     

Effects of consequences of advice on patterns of rule control and rule choice

Rules in the form of advice can inaccurately state the effects of recommended responses by overstating or understating size of the consequences. Three experiments investigated the effects of such inaccuracies on patterns of rule control and rule choice with female college students. In Experiment 1, signaled accurate, overstated, or understated rules specified that a given number of points would be earned by pressing a designated key. For some subjects, rules specified a number of points to be gained; for other subjects, rules specified a number of points to be lost from an amount given earlier. Point totals stated in the inaccurate rules averaged 25% more (overstated) or 25% less (understated) than those received. When subjects could choose either the response specified in the rule or an alternative response that produced an unpredictable number of points, they showed greater sensitivity to the inaccuracy of overstated rules than understated rules. In trials at the end of the experiment in which subjects could choose which rule to see, subjects did not always choose accurate rules and often chose inaccurate rules for which they had shown less sensitivity earlier. Experiment 2 replicated this pattern in which subjects could choose which type of rule to see on a greater number of trials. Some evidence suggested that subjects prefer an improvement from the outcomes promised to those later received. In Experiment 3, rules misstated by averages of 25% and 50% were compared. Evidence suggested that increasing the size of the misstatement reduced the discrimination of inaccurate rules from accurate ones.     

Buddhism and Science: Allies or Enemies?

Buddhist teachings and modern science are analogous both in their approach to the search for truth and in some of the discoveries of contemporary physics, biology, and psychology. However, despite these congruencies and the recognized benefits of science, Buddhism reminds us of the dangers of a tendency toward scientific reductionism and imperialism and of the sciences' inability to deal with human moral and spiritual values and needs. Buddhism and science have human concerns and final goals that are different, but as long as the boundaries between them are not trespassed, they can be mutually corrective and allied to benefit humankind. Buddhism must be open to the discoveries of science about the physical world as must all religions today, but no matter how much it may have to modify some of its ancient beliefs, its basic truths—the truths about human suffering and its release—will remain untouched.     

Subcellular interactions between parallel fibre and climbing fibre signals in purkinje cells predict sensitivity of classical conditioning to interstimulus interval

Classical conditioning of the nictitating membrane response requires a specific temporal interval between conditioned stimulus and unconditioned stimulus, and produces an incrase in Protein Kinase C (PKC) activation in Purkinje cells. To evaluate whether biochemical interactions within the Purkinje cell may explain the temporal sensitivity, a model of PKC activation byCa ²⁺, diacylglycerol (DAG), and arachidonic acid (AA) is developed.Ca ²⁺ elevation is due to CF stimulation and IP3 inducedCa ²⁺ release (IICR). DAG andIP ₃ result from PF stimulation, while AA results from phospholipase A2 (PLA ₂). Simulations predict increased PKC activation when PF stimulation precedes CF stimulation by 0.1 to 3 s. The sensitivity of IICR to the temporal relation between PF and CF stimulation, together with the buffering system of Purkinje cells, significantly contribute to the temporal sensitivity.     

An evaluation and comparison of time-out procedures with and without release contingencies

A common recommendation for implementing time‐out procedures is to include a release contingency such that the individual is not allowed to leave time‐out until no problem behavior has occurred for a specific amount of time (e.g, 30 s). We compared a fixed‐duration time‐out procedure to a release contingency time‐out procedure with 4 young children (3‐ and 4‐year‐olds) using a reversal and multielement design. Results demonstrated that both time‐out procedures were effective at reducing problem behavior outside time‐out, problem behavior occurred in time‐out during both procedures, and problem behavior in time‐out was not predictive of problem behavior outside time‐out.     

On the role of covarying functions in stimulus class formation and transfer of function

This experiment investigated whether directly trained covarying functions are necessary for stimulus class formation and transfer of function in humans. Initial class training was designed to establish two respondent-based stimulus classes by pairing two visual stimuli with shock and two other visual stimuli with no shock. Next, two operant discrimination functions were trained to one stimulus of each putative class. The no-shock group received the same training and testing in all phases, except no stimuli were ever paired with shock. The data indicated that skin conductance response conditioning did not occur for the shock groups or for the no-shock group. Tests showed transfer of the established discriminative functions, however, only for the shock groups, indicating the formation of two stimulus classes only for those participants who received respondent class training. The results suggest that transfer of function does not depend on first covarying the stimulus class functions.     

Global increase in response latencies by early middle age: complexity effects in individual performances

Ten young women (age 20 to 22 years) and 10 middle-aged women (age 36 to 44 years) served as subjects in choice reaction time, letter classification, and abstract matching-to-sample tasks. In each of seven conditions, the older group responded more slowly than the younger group. Age differences showed a complexity effect. That is, differences between the latencies of young and old subjects increased as the latency of the young subjects increased. Both linear and power functions accurately described the relation between the latencies of the middle-aged and young adult groups. This was true not only for the relation between average latencies but also for the relation between corresponding quartiles of latency distributions. Similar results were observed at the individual level: All middle-aged subjects showed complexity effects, and, for each middle-aged subject, the relation between her latencies and those of the average young adult was well described by linear and power functions. These findings indicate that age-related slowing is apparent by age 40, and that complexity effects are observable in individual performances. This slowing is global and not specific to particular tasks, as indicated by the fact that the latencies of older adults can be predicted directly from those of younger adults without regard to the nature of the task.