Relationship between response rate and reinforcement frequency in variable-interval schedules: II. Effect of the volume of sucrose reinforcement

Three rats were exposed to variable-interval schedules specifying a range of different reinforcement frequencies, using three different volumes of .32 molar sucrose (.10, .05, and .02 milliliters) as the reinforcer. With each of the three volumes, the rates of responding of all three rats were increasing, negatively accelerated functions of reinforcement frequency, the data conforming closely to Herrnstein's equation. In each rat the value of the constant K_H, which expresses the reinforcement frequency needed to obtain the half-maximal response rate, increased with decreasing reinforcer volume, the values obtained with .02 milliliters being significantly greater than the values obtained with .10 milliliters. The values of the constant R_max, which expresses the theoretical maximum response rate, were not systematically related to reinforcer volume. The effect of reinforcer volume upon the relationship between response rate and reinforcement frequency is thus different from the effect of the concentration of sucrose reinforcement: In a previous experiment (Bradshaw, Szabadi, & Bevan, 1978) it was found that sucrose concentration influenced the values of both constants, R_max increasing and K_H decreasing with increasing sucrose concentration.     

Relationship between response rate and reinforcement frequency in variable-interval schedules: the effect of the concentration of sucrose reinforcement

Four rats were exposed to variable-interval schedules specifying a range of different reinforcement frequencies, using sucrose of two different concentrations and distilled water as the reinforcer. With sucrose, the rates of responding of all four rats were increasing negatively accelerated functions of reinforcement frequency, the data conforming closely to Herrnstein's equation; this was also true of the data from three of the four rats when distilled water was used as the reinforcer. The values of both constants in Herrnstein's equation were related to the sucrose concentration: the asymptotic response rate decreased, and the reinforcement frequency corresponding to the half-maximal response rate increased, with decreasing sucrose concentration.     

Reinforcement value and substitutability of sucrose and wheel running: implications for activity anorexia

Choice between sucrose and wheel-running reinforcement was assessed in two experiments. In the first experiment, ten male Wistar rats were exposed to concurrent VI 30 s VI 30 s schedules of wheel-running and sucrose reinforcement. Sucrose concentration varied across concentrations of 2.5, 7.5, and 12.5%. As concentration increased, more behavior was allocated to sucrose and more reinforcements were obtained from that alternative. Allocation of behavior to wheel running decreased, but obtained wheel-running reinforcement did not change. Overall, the results suggested that food-deprived rats were sensitive to qualitative changes in food supply (sucrose concentration) while continuing to defend a level of physical activity (wheel running). In the second study, 15 female Long Evans rats were exposed to concurrent variable ratio schedules of sucrose and wheel-running, wheel-running and wheel-running, and sucrose and sucrose reinforcement. For each pair of reinforcers, substitutability was assessed by the effect of income-compensated price changes on consumption of the two reinforcers. Results showed that, as expected, sucrose substituted for sucrose and wheel running substituted for wheel running. Wheel running, however, did not substitute for sucrose; but sucrose partially substituted for wheel running. We address the implications of the interrelationships of sucrose and wheel running for an understanding of activity anorexia.     

Operant Conditioning Effects upon Drawing Content

Abstract

The variability of drawing content classes and the effects of the Ss awareness of contingencies were tested through an experimental reinforcement of human and object content. In three individual sessions 60 Ss completed drawings each time responding to 25 standardized perceptual cues. In the second session, two matched experimental groups were treated with reversed forms of reinforcement. A questionnaire and interview were used to refine the data. Findings show a significant consistency of several content classes; nevertheless, the contingent classes were efficiently conditioned. The male Ss and contingency-aware pairs conditioned better than the nonawareness and female Ss. The relative lack of extinction points to the persistent effects of reinforcement.     

The effect of token reinforcement on McCarthy Scale performance for white preschoolers of low and high social position

In Study 1, the effect of making tokens contingent on correct performance of low social position preschoolers on the McCarthy Scales of Children's Abilitieswas examined. Preschoolers in a token reinforcement group scored significantly higher (mean=8 IQ points) than subjects in a control group. In Study 2, the effect of tokens on McCarthyresults was examined as a function of social position in a 2×2 design. The high social position control group scored significantly above the low social position control. The low social position token reinforcement group, however, performed as well as both the high social position control and token reinforcement groups. Use of systematic reinforcement contingencies to reduce test error is discussed.     

Response latency as a function of amount of reinforcement

Food-deprived rats were trained to press and hold down a telegraph key in the presence of a light. Subsequent release of the key during a tone was followed by 0.15 ml of a 20-percent sucrose solution as reinforcement. The Ss were subsequently shifted to a 0-percent and to a 5-percent solution from the 20-percent base line. The median RT and the variability of RT increased markedly as a result of the shift to the lower sucrose concentrations. For all Ss, the change in median and variability was greater for the shift to the 0-percent solution than for the shift to the 5-percent solution. It is probable that median RT and variability of RT are inversely related to amount of reinforcement.     

Reinforcer magnitude (sucrose concentration) and the matching law theory of response strength

This experiment investigated the relationship between reinforcer magnitude (sucrose concentration) and response rate. The purpose was to evaluate the behavior of two parameters of an equation that predicts absolute response rate as a function of reinforcement rate and two free parameters. According to Herrnstein's (1970) theory of reinforced behavior, one parameter of this "response-strength equation" measures the efficacy of the reinforcer maintaining responding and the other parameter measures motoric components of response rate, such as response duration. Seven rats served as subjects. Experimental sessions consisted of a series of five different variable-interval schedules of reinforcement, each in effect for 5 minutes. Within each session, obtained reinforcement rates varied over more than a 30-fold range, from about 20 per hour to 700 per hour. The reinforcer was sucrose solution, and, between sessions, its concentration was varied from 0.0 to 0.64 molar (0 to 21.9%). For sucrose concentrations of 0.16 to 0.64 m, response rate was a negatively accelerated function of reinforcement rate. Increases in sucrose concentration increased response rates maintained by low but not high reinforcement rates. This pattern of changes corresponds to a change in the reinforcement-efficacy parameter of the response-strength equation. In contrast, the motor-performance parameter did not change as a function of sucrose concentration. These findings are inconsistent with the results of a similar study (Bradshaw, Szabadi, & Bevan, 1978) but support Herrnstein's theory of reinforced behavior.     

A Preliminary Investigation of the Effects of Reading Fluency Interventions on Comprehension

Abstract

Brief experimental analyses were conducted using two dependent variables to evaluate the effectiveness of reading interventions. Specifically reading rate (words read correctly per minute) and mean reading comprehension levels for six students with reading difficulties were obtained using six different reading intervention/intervention combinations. These interventions included contingent reinforcement, listening passage preview, repeated reading, listening passage preview with contingent reinforcement, repeated reading with contingent reinforcement, and repeated reading with listening passage preview. Results suggested that no one intervention was best for all students. In addition, it was found that interventions that increased reading rate for half of the students also increased reading comprehension for the same students. Discussion focuses on student-treatment interactions, measuring student reading performance, matching treatments to students, and directions for future research.     

Training Correspondence by Reinforcing Intermediate and Verbal Behavior

Different procedures have been used in the past to control the correspondence between verbal and its related nonverbal behavior. This study proposes a variant of these procedures for controlling that correspondence. This variant caIls for reinforcement contingent on related intermediate behaviors. Intermediate behaviors are those that occur between verbal behavior and its related nonverbal behavior. Ten preschool chiIdren ranging in age from 3 to 5 years, served as subjects. In this study, reinforcement was applied either to promises to engage in a certain activity later or to a series of intermediate behaviors specified for each of four preschoo1 activities. Consistently higher levels of correspondence occurred after reinforcement of intermediate behaviors in comparison to reinforcement of promises.     

Martin Bucers Deutsche Schriften: Current Work,Future Projects

Abstract

The edition of Martin Bucer's German writings has often puzzled its readers by the varying frequency with which its volumes have been published as well as by the order in which these have been published. The very first volume of the edition went to press in 1960.¹ Volume Two, which appeared in 1962,² was followed in 1964 not by Volume Three but by Volume Seven.³ Whereas these volumes had been produced in intervals of two years, it took a total of 14 years for Volumes Three, Four and Five⁴ to be edited, the latter of which was printed in 1978. The next volume to appear carried the number 17,⁵ thus skipping the numbers of 11 volumes which had yet to be edited. The Sixth Volume, which began appearing in 1984, was edited in three separate instalments,⁶ the last of which was printed in 1988. Each one of these instalments could be considered a volume in its own right. Then, in 1995, the first part of Volume Nine was published, also a volume in its own right with the number 9,1,⁷ the first part of Volume 11 in 1999,⁸ and Volume Ten went to press in March of 2001.⁹ Thus a total of thirteen volumes have been produced in a matter of fourty-one years, an average of somewhat over three years per volume. This statistic obscures the sometimes significant hiatuses between the appearances of certain volumes, the longest of which included six years between Volumes Three and Four, and even seven years between Volumes 6,1 and 9,1.

Anybody leafing through the first three volumes and comparing them will immediately note that they neatly fit within a broader chronological continuum. Volume One bears the title Early writings: 1520 to 1524,¹⁰ Volume Two Writings of the years 1524 to 1528,¹¹ and Volume Seven is entitled Writings of the years 1538 to 1539.¹² These titles suggest a strictly chronological conception of the entire edition. On the other hand, the last volume to appear, number Ten, carries a thematic title: Writings on marriage and matrimonial law¹³ and includes writings ranging all the way from 1524 to 1543. It is therefore obvious that a major change in the conception of the edition as a whole has taken place between those early volumes and the last one.     

Successive discrimination training with equated reinforcement frequencies: failure to obtain behavioral contrast

In two experiments, pigeons were trained on two-component multiple schedules in which responding in one component (S₁) was always maintained by a variable-interval schedule. In Experiment I, low response rates were reinforced in the second (S₂) component for six master subjects. This schedule was adjusted to equate reinforcement frequencies in the two components. These subjects were compared to yoked partners, for which reinforcement in the S₂ component was made available on a variable-interval schedule whose value was determined by the master subjects. A similar procedure was used in Experiment II, where the S₂ schedule for master subjects made reinforcers contingent on the absence of responding. No evidence was found in either experiment for a behavioral contrast effect in the S₁ component attributable to response reduction in the S₂ component. A reliable contrast effect was obtained from a group of pigeons given extinction conditions in the S₂ component, which was compared to a group maintained throughout on a multiple variable-interval schedule. The results suggest that previous indications of behavioral contrast in similar situations were probably caused by uneven reinforcement distributions or reflect uncontrolled fluctuations in response rates.     

“Me”, “We”, and Materialism: Associations between Contingent Self-Worth and Materialistic Values across Cultures

Abstract

Individuals with high levels of externally contingent self-worth tend to base their self-esteem on factors such as appearance, competitive success, and others’ approval. Such tendencies might also elevate people’s focus on material possessions. However, cultural moderation of these associations has yet to be explored. A cross-cultural survey among Chinese and Dutch college students examined the link between externally-based contingent self-worth and materialistic values, as well as the mediating roles of need to belong and need for self-enhancement. An initial multi-group path analysis indicated a stronger link between externally contingent self-worth and materialism for Chinese students than for Dutch students. For both Chinese and Dutch students, externally contingent self-worth was positively related to materialistic values, need to belong, and need for self-enhancement. Need to belong and need for self-enhancement were positively linked with materialism, and need to belong and need for self-enhancement mediated the link between externally contingent self-worth and materialism. Though the indirect effect via self-enhancement was somewhat stronger among Chinese participants, this research demonstrates that people’s externally contingent self-worth might be a factor predicting materialism across cultures, with need to belong and need for self-enhancement playing similar roles as underlying processes in different societies.     

Individual Behavior Consistencies as Interactive Styles: Their Relation to Personality

Two experimental studies were carried out in order to find within-subject consistencies as individual differences in a concurrent choice situation simulating risk-taking. In a first experiment, six adults were exposed to different values of probability and numbers of reinforcement in a task involving betting on two simultaneous horse races displayed on a microcomputer monitor. In the second experiment, two subjects were exposed to a within-session replication of the first experiment. The results in both experiments support the reliability of within-subject consistencies when experimental tasks are built as open contingencies. The conceptual and experimental implications of the data are discussed in relation to the study of personality.

     

CONTINGENT PAYMENT PROCEDURES FOR SMOKING REDUCTION AND CESSATION

We assessed the ability of a combined contingent reinforcement and intensive monitoring procedure to promote and sustain temporary smoking cessation among 34 hired research volunteers, and the ability of a smoking reduction test to predict the subsequent initiation of abstinence. During the 5-day cutdown test, subjects were paid from $0 to $6 per day depending on the extent of reduction from baseline CO levels. During the abstinence test, breath samples were obtained three times daily and subjects were paid $4 for each CO reading ≤11 ppm. Sixty-eight percent of subjects initiated abstinence. Of the breath samples collected during the abstinence test (91% of scheduled samples), 96.5% were ≤11 ppm and 80.5% were ≤8 ppm. Subjects who earned more money during the cutdown test were more likely to abstain (r = ?0.51, p < .001). Contingent reinforcement and intensive monitoring procedures appear to have usefulness for analog studies of smoking reduction and cessation.     

The Rapid Establishment of Low-Rate Fixed Interval Responding by Humans in a Single Experimental Session

Subjects responding to receive monetary reinforcement on a fixed interval schedule were read instructions containing varying amounts of information regarding the schedule contingencies prior to their participation in the experiment. In addition, some subjects were exposed to an additional response cost contingency for early responding. The results indicate that reliable low-rate fixed interval responding can be rapidly generated in a single 45-minute experimental session when subjects are provided with explicit instructions together with the response cost contingency.

     

Response acquisition by zebrafish (Danio rerio) with delayed reinforcement

Zebrafish (Danio rerio) is a common vertebrate animal model in biomedical research and is a promising species for studying how genes interact with environmental factors in determining behavior. The present study investigated how reinforcement parameters affect zebrafish behavior by assessing response acquisition with delayed reinforcement, which has been studied with other species (e.g., rats, pigeons, humans, etc.) but not with zebrafish. Twenty‐four experimentally naïve subjects were exposed to a tandem fixed‐ratio 1 differential‐reinforcement‐of‐other‐behavior x‐s schedule of reinforcement, where x varied across subjects. There were six different delay‐to‐reinforcement durations and sets of four fish were assigned to each delay duration. All of the fish assigned to a 0‐, 0.5‐, or 1‐s delay acquired responding. Two fish acquired responding with a 3‐s delay and one fish appeared to have acquired it with a 6‐s delay although the latter result was less clear. None acquired responding with a 12‐s delay. These results suggest that zebrafish behavior is sensitive to delays to reinforcement and the time frame over which reinforcement is effective may be limited approximately to 6 s. This time frame is shorter than that found with other species. Practical and theoretical implications of the present finding are discussed.     

Melloration and maximization of reinforcement minus costs of behavior

Eight pigeons were exposed to independent concurrent schedules. Concurrent variable-interval 60-second variable-interval 60-second schedules were presented to one group of four subjects. Following baseline training, a limited hold was added to one of the schedules and the duration of the hold was decreased in successive conditions. Concurrent variable-interval 120-second variable-interval 40-second schedules were presented to another group of four subjects. These subjects were first exposed to decreasing durations of a limited hold in the variable-interval 40-second component. After replication of the baseline, a limited hold in the variable-interval 120-second component was decreased in duration. The initial durations of the holds were determined from the subjects' responding in the baseline conditions. A duration was chosen such that approximately 25% of the scheduled reinforcers would be canceled if responding remained unchanged.

Approximate matching of time proportions and reinforcement proportions was observed when the limited hold was added to the variable-interval 60-second schedule and when the limited hold was added to the variable-interval 40-second schedule. Time proportions were less extreme than reinforcement proportions when the limited hold operated in a variable-interval 120-second schedule. Overall reinforcement rates tended to decrease with continued training in concurrent schedules with a limited hold. Absolute deviations from time matching also decreased. The results provide evidence against the principle of reinforcement maximization, and support Herrnstein and Vaughan's (1980) melioration hypothesis.

     

Aging is associated with increased Weber ratios

To investigate whether age-associated changes in the human taste system are quality-specific, we compared young and elderly subjects’ suprathreshold discrimination abilities for caffeine and sucrose. The method of constant stimuli was used to obtain just noticeable differences and Weber ratios. The elderly generated larger Weber ratios than did the young for both the medium and high concentrations of caffeine, but not for the low concentration. For example, a 74% increase in .005 M caffeine was required to obtain a perceptible difference for the elderly, whereas a 34% increase produced a perceptible difference for the young. The Weber ratios for sucrose did not differ for the two age groups. The results of this study indicate that age-associated changes in the taste system are quality-specific.

     

Monogeusia for fructose,glucose, sucrose,and maltose

We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations ≦ 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with themonochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugarsmonogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.     

Learned helplessness: Not dependent upon cognitions, attributions, or other such phenomenal experiences

Subjects shot a light gun at a target with a photorecepter cell in the bull's-eye, with the only information regarding their accuracy being provided by reinforcing tone signals. Half the subjects received reinforcers contingent upon their hits. The others were yoked to the contingent subjects, receiving non-contingent reinforcers in the same patterns. Experiment 1 compared contingent or noncontingent positive or aversive reinforcers in their effect on subsequent anagrams performance. Phenomenal experiences, such as cognitive awareness, attributions, and moods, were assessed. Subjects exhibited a strong helplessness effect independent of their phenomenal experiences. In Experiment 2 the independent variables of contingent/noncontingent reinforcement and awareness of noncontingency were manipulated orthogonally by informing half the subjects that their reinforcement had been noncontingent in the target-shooting. Actual noncontingency produced a strong helplessness effect whereas “awareness of noncontingency” did not.