Typical delay determines waiting time on periodic-food schedules: Static and dynamic tests

Pigeons and other animals soon learn to wait (pause) after food delivery on periodic-food schedules before resuming the food-rewarded response. Under most conditions the steady-state duration of the average waiting time, t, is a linear function of the typical interfood interval. We describe three experiments designed to explore the limits of this process. In all experiments, t was associated with one key color and the subsequent food delay, T, with another. In the first experiment, we compared the relation between t (waiting time) and T (food delay) under two conditions: when T was held constant, and when T was an inverse function of t. The pigeons could maximize the rate of food delivery under the first condition by setting t to a consistently short value; optimal behavior under the second condition required a linear relation with unit slope between t and T. Despite this difference in optimal policy, the pigeons in both cases showed the same linear relation, with slope less than one, between t and T. This result was confirmed in a second parametric experiment that added a third condition, in which T + t was held constant. Linear waiting appears to be an obligatory rule for pigeons. In a third experiment we arranged for a multiplicative relation between t and T (positive feedback), and produced either very short or very long waiting times as predicted by a quasi-dynamic model in which waiting time is strongly determined by the just-preceding food delay.     

Time-place learning by pigeons, Columba livia

In each of two experiments, 2 pigeons received discrimination training in which food reinforcement for key pecking was conditional upon both spatial and temporal cues. In Experiment 1, food was available for periods of 30 s at each of three locations (pecking keys) during trials that lasted 90 s. In Experiment 2, food was available for periods of 15 min at each of four locations (pecking keys) during a 60-min trial. In both experiments, pigeons' key pecking was jointly controlled by the spatial and temporal cues. These data, and other recent experiments, suggest that animals learn relationships between temporal and spatial cues that predict stable patterns of food availability.     

Assessing the relationship of Type A beliefs to cardiovascular disease risk and psychosocial distress

Investigators have begun to take a multimodal approach to the assessment and treatment of psychosocial risk factors for cardiovascular disease (CVD). For instance, cognitive responses have become the focus of contemporary research along with continued examination of overt Type A behaviors. Price (1982) has outlined a set of beliefs purportedly associated with Type A behavior and subsequent CVD risk. The current study examines the validity of this belief set as represented by a newly developed measure, the Type A Cognitive Questionnaire (TACQ). Subjects were 221 employed adults participating in a worksite CVD risk reduction program. They completed the TACQ as part of a pretreatment CVD risk screening protocol. As hypothesized, TACQ scores were significantly associated with Type A behavior, hostility, physiological mediators of CVD, and psychosocial distress. Discussion addresses continued refinement of the Type A belief construct.     

The interaction of stimulus and reinforcer control in complex temporal discrimination.

Six pigeons were trained in a discrete-trials signal-detection procedure to discriminate between a fixed-duration stimulus (5 s or 20 s) and a set of variable durations ranging from 2.5 s to 57.5 s in steps of 5 s. For each fixed-duration stimulus, the ratio of reinforcer frequencies contingent upon reporting the fixed versus the variable stimulus was systematically manipulated. Detection performance was well controlled by both the stimulus value and the reinforcer ratio. Both the discriminability between the fixed duration and the set of variable durations, and the discriminability between the fixed duration and each of the variable durations, were independent of the reinforcer-frequency ratio when discriminability was measured as log d. The sensitivity of response bias to reinforcement-ratio changes was independent of the value of the fixed duration, but was not independent of the discriminability of the variable durations from the fixed durations. Under current models, discriminability measures in complex temporal discrimination may be independent of biasing manipulations, but bias measures are not independent of stimulus values.     

Delayed temporal discrimination in pigeons: A comparison of two procedures

A within-subjects comparison was made of pigeons' performance on two temporal discrimination procedures that were signaled by differently colored keylight samples. During stimulus trials, a peck on the key displaying a slanted line was reinforced following short keylight samples, and a peck on the key displaying a horizontal line was reinforced following long keylight samples, regardless of the location of the stimuli on those two choice keys. During position trials, a peck on the left key was reinforced following short keylight samples and a peck on the right key was reinforced following long keylight samples, regardless of which line stimulus appeared on the correct key. Thus, on stimulus trials, the correct choice key could not be discriminated prior to the presentation of the test stimuli, whereas on position trials, the correct choice key could be discriminated during the presentation of the sample stimulus. During Phase 1, with a 0-s delay between sample and choice stimuli, discrimination learning was faster on position trials than on stimulus trials for all 4 birds. During Phase 2, 0-, 0.5-, and 1.0-s delays produced differential loss of stimulus control under the two tasks for 2 birds. Response patterns during the delay intervals provided some evidence for differential mediation of the two delayed discriminations. These between-task differences suggest that the same processes may not mediate performance in each.     

Competitive fixed-interval performance in humans

Two persons responded in the same session in separate cubicles, but under a single schedule of reinforcement. Each time reinforcement was programmed, only the first response to occur, that is, the response of only one of the subjects, was reinforced. “Competitive” behavior that developed under these conditions was examined in three experiments. In Experiment 1 subjects responded under fixed-interval (FI) 30-s, 60-s, and 90-s schedules of reinforcement. Under the competition condition, relative to baseline conditions, the response rates were higher and the pattern was “break-and-run.” In Experiment 2, subjects were exposed first to a conventional FI schedule and then to an FI competition schedule. Next, they were trained to respond under either a differential-reinforcement-of-low-rate (DRL) or fixed-ratio (FR) schedule, and finally, the initial FI competition condition was reinstated. In this second exposure to the FI competition procedure, DRL subjects responded at lower rates than were emitted during the initial exposure to that condition and FR subjects responded at higher rates. For all subjects, however, responding gradually returned to the break-and-run pattern that had occurred during the first FI competition condition. Experiment 3 assessed potential variables contributing to the effects of the competitive FI contingencies during Experiments 1 and 2. Subjects were exposed to FI schedules where (a) probability of reinforcement at completion of each fixed interval was varied, or (b) a limited hold was in effect for reinforcement. Only under the limited hold was responding similar to that observed in previous experiments.     

Behavioral contrast in fixed-interval components: effects of extinction-component duration.

Seven albino rats were exposed to a multiple schedule of reinforcement in which the two components (fixed interval and extinction) alternated such that a presentation of the extinction component followed each fixed-interval reinforcement. In baseline sessions, the duration of the extinction component was constant and always one-third of the fixed-interval value. Probe sessions contained a probe segment in which the duration of the extinction component was increased; the response rate in fixed-interval components during the probe segment was compared with the response rate in the segments preceding and following the probe. The effect of increasing the duration of the extinction component was studied under three values of fixed interval: 30 s, 120 s, and 18 s, in three successive conditions. Response rate within fixed intervals was a direct function of duration of the extinction component. Pausing at the beginning of the fixed interval decreased as extinction duration increased. These effects were larger and more consistent for the shorter fixed-interval values (18 s and 30 s). These results indicate a functional relation between relative component duration and responding. For the component providing more frequent reinforcement, this could be stated as an inverse relationship between relative component duration and response rate. This relation is similar to findings regarding the ratio of trial and intertrial duration in Pavlovian conditioning procedures, and suggests that behavioral contrast may be related to Pavlovian contingencies underlying the multiple schedule.     

Temporal control by signals of interval duration within variable-interval schedules

Rats' lever pressing produced sucrose reinforcers on a variable-interval schedule where, in different conditions, the duration of a stimulus presented immediately after reinforcement was either correlated or uncorrelated with the duration of the current interreinforcement interval. Under the baseline schedule, in which no stimulus was presented, the minimum interreinforcement interval was 8 s and the mean postreinforcement pause of each subject approximated this value. Response rates increased slowly over the first 10 to 15 s and then remained roughly constant throughout the remainder of the interval. In both the correlated and uncorrelated conditions, the added stimulus resulted in the postreinforcement pauses lengthening to values in excess of the duration of the preceding stimulus. This resulted in a poststimulus pause which was, in most cases, roughly constant irrespective of the duration of the preceding stimulus, or of the reinforcement contingencies prevailing immediately after stimulus offset. Local response-rate patterns in the uncorrelated conditions were similar to those obtained under the baseline schedule in which no stimulus was presented. However, in the correlated condition local response rates increased across the remainder of the interreinforcer interval. Further, the rate of acceleration was inversely related to the duration of the preceding stimulus. These results show that a correlation between stimulus duration and the ensuing time to reinforcement can control behavior—a type of temporal control not previously reported.     

Typical coping patterns: A person-centered approach to coping

Applying the person-oriented approach to coping can provide a unique perspective by revealing typical latent patterns. The study examined typical latent patterns shown by task-, emotion- and avoidance-oriented trait-based coping styles. We performed secondary analyses with Latent Profile Analysis on our former data and three independent datasets containing coping measures with the CISS-48 scale (Endler & Parker, 1994). Gender differences were also studied. Two basic profiles seem universal: the first is characterized by a high level of task-oriented coping, and the second profile is with moderately high scores on all three coping styles. The finding indicates that two fundamental latent coping profiles exist, which suggests a within-subject comparison in practice instead of investigating the absolute value of coping styles. Comparing data before and after 2020, COVID-19 does not seem to affect these profiles. The person-centered approach provides a possibility for the integration of coping-related findings.     

Reciprocal relationships between personality traits and psychological well-being

This study used an American sample collected over a period of approximately 2 decades (at 3 time points) to examine the temporal relationships between psychological well-being and personality traits (i.e., neuroticism, extraversion, agreeableness, conscientiousness, and openness to experience). The random-intercept cross-lagged panel model was used to separate between-person and within-person sources of variation. Between-person correlations were comparable to those of previous studies. New insights were gained at the within-person level. There were reciprocal relationships between psychological well-being and openness and extraversion, suggesting the joint development of plasticity-related traits and well-being over time. The relationships between psychological well-being and conscientiousness and agreeableness were unidirectional, with psychological well-being preceding these traits. Despite a strong between-person association between neuroticism and psychological well-being, the two were not related at the within-person level.