Clock control of human performance on avoidance and fixed-interval schedules

Resource limitations: A taxonomy

Decision making within the context of resource limitations requires balancing the short-term benefits of obtaining a resource and the long-term consequences of depleting those resources. The present manuscript focuses on four types of tasks that share this tradeoff to develop a taxonomy that will encourage a deeper understanding of the psychological processes at play. The four types considered are foraging, common pool traps, deterioration traps, and a novel designation referred to as resource cliffs. All four will be shown to include two opposite processes - depletion of the resource and its replenishment over time. By considering the unique and shared features of these tasks, a taxonomy of features emerges that can be combined to not only create novel tasks but also to shift the research focus to task features rather than specific tasks. The paper closes with a consideration of current theoretical frameworks previously applied to one or more of these resource-limitation tasks as well as the promise of reinforcement learning as a unifying theory.

The fixed-interval scallop in human affairs

"Fixed-interval scalloping" is used to describe certain everyday patterns of behavior in textbooks and other educational communications. This is a misleading use of the term. It implies that the behavior is accounted for by the schedule, when, in fact, many other variables are operating. This paper reviews eleven such variables and the research evidence on them. These variables provide a more adequate account of complex behavior and point up areas of limited knowledge requiring further research in both laboratory and applied settings. Extrapolating from basic research on human fixed-performance suggests that there are phenomena of mutual interest to both basic and applied behavior analysts.

Analyzing the reinforcement process at the human level: can application and behavioristic interpretation replace laboratory research?

Critics have questioned the value of human operant conditioning experiments in the study of fundamental processes of reinforcement. Contradictory results from human and animal experiments have been attributed to the complex social and verbal history of the human subject. On these grounds, it has been contended that procedures that mimic those conventionally used with animal subjects represent a "poor analytic preparation" for the explication of reinforcement principles. In defending the use of conventional operant methods for human research, we make three points: (a) Historical variables play a critical role in research on processes of reinforcement, regardless of whether the subjects are humans or animals. (b) Techniques are available for detecting, analyzing, and counteracting such historical and extra-experimental influences; these include long-term observations, steady state designs, and, when variables are not amenable to direct control (e.g., age, gender, species), selection of subjects with common characteristics. (c) Other forms of evidence that might be used to validate conditioning principles-applied behavior analysis and behavioristic interpretation-have inherent limitations and cannot substitute for experimental analysis. We conclude that human operant conditioning experiments are essential for the analysis of the reinforcement process at the human level, but caution that their value depends on the extent to which the traditional methods of the experimental analysis of behavior are properly applied.

Temporal patterns of behavior from the scheduling of psychology quizzes

Temporal patterns of behavior have been observed in real-life performances such as bill passing in the U.S. Congress, in-class studying, and quiz taking. However, the practical utility of understanding these patterns has not been evaluated. The current study demonstrated the presence of temporal patterns of quiz taking in a university-level introductory psychology course and used these patterns to manage the traffic of quiz takers in a computerized testing lab. Results are discussed in terms of the applications of tracking temporal response patterns.

Reinforcement of human observing behavior by a stimulue correlated with extinction or increased effort

Young men pulled a plunger on mixed and multiple schedules in which periods of variable-interval monetary reinforcement alternated irregularly with periods of extinction (Experiment 1), or in which reinforcement was contingent on different degrees of effort in the two alternating components (Experiment 2). In the baseline conditions, the pair of stimuli correlated with the schedule components could be obtained intermittently by pressing either of two observing keys. In the main conditions, pressing one of the keys continued to produce both discriminative stimuli as appropriate. Pressing the other key produced only the stimulus correlated with variable-interval reinforcement or reduced effort; presses on this key were ineffective during periods of extinction or increased effort. In both experiments, key presses producing both stimuli occurred at higher rates than key presses producing only one, demonstrating enhancement of observing behavior by a stimulus correlated with the less favorable of two contingencies. A control experiment showed that stimulus change alone was not an important factor in the maintenance of the behavior. These findings suggest that negative as well as positive stimuli may play a role in the conditioned reinforcement of human behavior.

Conditioned reinforcement of human observing behavior by descriptive and arbitrary verbal stimuli

College students earned monetary reinforcers by pressing a key according to a compound schedule with variable-interval and extinction components. Pressing additional keys occasionally produced displays of either of two verbal stimuli; one was uncorrelated with the schedule components, and the other was correlated with the extinction component. In Experiments 1 and 2, the display area of the apparatus was blank unless an observing key was pressed, whereupon a descriptive message appeared. Most students preferred an uncorrelated stimulus stating that "Some of this time scores are TWICE AS LIKELY as normal, and some of this time NO SCORES can be earned" over a stimulus stating that "At this time NO SCORES can be earned." In Experiment 3, the display area indicated that "The Current Status of the Program is: NOT SHOWN." Presses on the observing keys replaced this message with stimuli that provided arbitrary labels for the schedule conditions. All of the students preferred a stimulus stating that "The Current Status of the Program is: B" over an uncorrelated stimulus stating that "The Current Status of the Program is: either A or B." Thus, under some circumstances, observing was maintained by a stimulus correlated with extinction-a finding that poses a challenge for Pavolvian accounts of conditioned reinforcement. Differences in the maintenance of observing by the descriptive and arbitrary stimuli may be attributed to differences in either the strength or nature of the instructional control exerted by the verbal stimuli.

Contingency-shaped and rule-governed behavior: instructional control of human loss avoidance

Instructions can override the influence of programmed schedules of reinforcement. Although this finding has been interpreted as a limitation of reinforcement schedule control in humans, an alternative approach considers instructional control, itself, as a phenomenon determined by subjects' reinforcement histories. This approach was supported in a series of experiments that studied instructional and schedule control when instructions either did or did not accord with the schedule of reinforcement. Experiment I demonstrated that accurate instructions control discriminative performances on multiple avoidance schedules, and that such control persists in a novel discrimination. Experiments II and III showed that elimination of instruction-following occurs when inaccurate instructions cause subjects to contact a monetary loss contingency. Experiment IV demonstrated the reinforcing properties of accurate instructions. Skinner's view of rule-governed behavior is consistent with these findings, and can be extended to account for many aspects of instructional control of human operant behavior.

Variable-ratio conditioning history produces high- and low-rate fixed-interval performance in rats

Four rats were exposed to an A-B-A-B series of 30 sessions each of variable-ratio 20 (A) and fixed-interval 30-s (B) schedules. Four other rats received 120 sessions of fixed-interval 30 s. The rats with a history of variable-ratio responding subsequently showed primarily high or low response-rate patterns on the fixed-interval schedule without evidence of classical scalloping (i.e., increased rates of responding throughout the interreinforcement interval), except infrequently in 1 rat. The rats exposed to only the fixed-interval 30-s schedule displayed the expected sequence of scalloping giving way to lower rate break-run or simply low-rate responding over time. This experiment shows that when naive rats are exposed to even a simple history of reinforcement (in this case, a variable-ratio 20), their subsequent fixed-interval performance is very different from comparable performance in naive rats, and might be said to be more similar to the responding of adult humans. The argument is made that care should be taken in comparing the fixed-interval performance of humans and nonhumans because humans have a complex history of reinforcement, whereas laboratory nonhumans are typically naive.

Verbal responding under a fixed-interval schedule: effects of D-amphetamine

The purpose of this study was to characterize the effects of d-amphetamine (5-30 mg) on rate and distribution of verbal responding which was maintained under a fixed-interval (FI) schedule of reinforcement. Hired volunteer subjects simultaneously wrote and spoke narrative monologues; points were delivered under a multiple 5 min fixed-interval 1 min time out schedule for closure of a voice operated relay (VOR). Under placebo control conditions, most subjects paused for 2-4 minutes following the 1 min time out then spoke and wrote during later portions of the interval. d-Amphetamine increased both the number of words written and seconds of VOR closure in a dose-related manner. In subjects who showed typical FI response patterning, the drug generally decreased the length of early interval pausing and increased low control amounts of verbal responding which occurred early in the interval proportionately more than higher amounts of verbal responding seen during later portions of the interval. These drug effects on response patterning were generally similar to those seen in infrahuman species responding under fixed-interval schedules of reinforcement.