Reinforcement rate and force proportional reinforcement

The research examines the consequences of making two reinforcement contingencies simultaneously available for the same bar-pressing response. Specifically, two experiments are described which concern the effects of reinforcement rate upon force proportional reinforcement (FPR). In Experiment 1, reinforcement rate was constrained by combining differential reinforcement of low rate with a force-proportional reinforcement contingency. The group of rats exposed to this regimen eventually showed a significant increase in response force compared to control groups. Experimental vs control response rates were not significantly different. In Experiment 2, reinforcement rate was affected through the expedient of relating the probability of obtaining a single pellet to the response force. The group for which the probability-force relationship was discontinuous came to exert higher forces than either a group for which the relationship was fairly continuous or an ordinary variable ratio control group. Response rate was significantly higher for the control group.     

Cardiac deceleration in newborns: habituation, dishabituation, and offset responses.

Twenty healthy, 1–4 day-old infants were selected from a sample of 135 neonates on the basis of alertness during testing. The infants were presented mild intensity colored light with gradual onset and offset while heart rate was monitored. Half the infants received six exposures to blue light followed by two exposures to blue-green light, whereas remaining subjects received colors in reverse order. Stimulus duration was 20 sec and variable periods between stimuli averaged 30 sec. Results of trend analysis of variance of the second-by-second cardiac data indicated that for infants older than the median age, the decelerative responses to both stimulus onset and offset were significant. Further, these subjects' onset decelerations significantly habituated within the six stimulus repetitions and significantly dishabituated with change in the stimulus color. Offset decelerations incremented over habituation trials and decremented with change in stimulus color. Responses of younger subjects were more variable which probably reflects their less complete recovery from the effects of maternal medication and the birth process.     

The relationship of moral judgment, self-awareness, and sex to complicance behavior

Sixty male and sixty female college students, representing three of Kohlberg's stages of moral judgment, were exposed to a complicance situation in which their personal count of a series of metronome clicks was contradicted by a unanimous group. Group differences were either one or two steps from veridical. For half of the subjects self-awareness was experimentally increased. The results indicated that subjects in moral judgment Stages 3 and 4 complied significantly more than Stage 5 subjects. The self-awareness manipulation produced a complex pattern of results in the form of a three way interaction with moral judgment and type of compliance. Finally, sex differences in compliance behavior were significant, with females complying more than males. The results were discussed in terms of a cognition-behavior relationship.     

Response discriminative and reinforcement factors in stimulus control of performance on multiple and chained schedules of reinforcement

Discriminative control of the response rates of two groups of rats was equated by training them to cease bar pressing in light-out no-tone ( + ) and to respond during tone and light. Multiple-schedule subjects received food at the same rate for responding during tone or light as for nonresponding in + . For the chained-schedule subjects responding in tone or light only produced + where food was received for nonresponding. In extinction tests multiple-schedule subjects emitted approximately twice the responses to tone-plus-light as to tone or light presented individually (additive summation). The rats trained on the chained schedule, in which the tone and light each controlled substantial response rates but were never paired with food, showed no summation when the tone and light were presented together. The results indicate that discriminative control of response rates and reinforcement differences between schedule components determine stimulus control.     

Reinforcement magnitude effects in first- and second-order conditioning of directed action

Three experiments investigated the effects of reinforcement magnitude on conditioned key pecking in pigeons. Experiment 1, which included between-groups and within-subject designs, yielded significant effects of unconditioned stimulus (US) magnitude on the within-conditioned stimulus (CS) distribution of key pecks and on choice behavior, but no effect on the overall rate of key pecking. Experiment 2 employed a larger US-magnitude difference in a within-subject design. This manipulation resulted in differential rates of key pecking as well as a significant choice effect and differential within-CS key-peck distributions. A second-order conditioning procedure was used in Experiment 3, in which diffuse, visual stimuli (S1's) served as Pavlovian reinforcers for two key-light S2's. The S1 previously paired with a large US was more effective in conditioning second-order key-peck behavior to an S2 than was the S1 paired with a small US. The results of these experiments demonstrate that the associative effects of US magnitude can be expressed in the strength of CS-directed motor responding. The distinctive within-CS key-peck distributions in first-order conditioning suggests an interaction between CS- and US-directed responses.     

Preference as a function of the correlation between stimuli and reinforcement outcomes

Pigeons' preferences for stimuli that were to varying degrees correlated with outcomes were studied in two experiments using a concurrent-chain procedure. The pigeons chose between two terminal links, each ending with food reinforcement and with blackout on half of the trials. In the first experiment, one terminal link (nonpredictive or unreliable link) provided stimuli completely uncorrelated with the outcomes while the other terminal link (predictive or reliable link) provided stimuli that were, to varying degrees, correlated with these outcomes. All pigeons showed increasing preferences for the predictive link as the reliability of the stimuli in that link increased. In the second experiment, stimuli in both terminal links were differentially correlated with the outcomes. The pigeons again preferred the more reliably correlated terminal link. The relation between these results and the delay-reduction hypothesis and conditioned reinforcement account is noted. The behavioral value of predictive stimuli may lie in their permitting the organism to more effectively apportion its time between interim activities and terminal responses.     

Polydipsia induced by a schedule of brain stimulation reinforcement

Rats pressed a lever for a signaled brain stimulation reinforcement on either fixed-interval or fixed-ratio schedules. Both schedules induced polydipsia, with a median water intake of 22.5 ml (about four times the control level) in 3-hr sessions. The stimulation did not directly elicit drinking or other behaviors. In a second experiment, two out of four rats became polydipsic during extinction following a continuous schedule of brain stimulation reinforcement. The results were compared with previous attempts to induce polydipsia with a schedule of brain stimulation reinforcement and were discussed in terms of polydipsia as a model of human “compulsive” behaviors.     

The ambiguous-cue problem: The effects of reduced similarity between trials and the schedule of reinforcement

In a series of seven experiments pigeons were trained on the two-choice ambiguous-cue problem that contains PA and NA trials. On PA trials choice of P (the positive stimulus) was reinforced and choice of A (the so-called ambiguous stimulus) was not reinforced; on NA trials choice of A was reinforced and choice of N (the negative stimulus) was not reinforced. When the two types of trials were distinguished by only the presence of P or N and each trial was terminated by one response, subjects quickly attained high levels of performance on NA trials but showed only chance levels of performance on PA trials. PA performance was markedly improved when a variety of additional stimuli distinguished the two types of trials and when a variety of schedules of intermittent reinforcement were employed; these manipulations had little effect on NA performance.     

Stimulus control and delayed reinforcement

Pigeons were tested for generalization along the line-orientation dimension, after being trained on various two-component multiple schedules. The first component contained either a variable-interval 1-min schedule of immediate reinforcement or an extinction schedule and was associated with a plain white key (S1). The second component contained a variable-interval 1-min schedule of delayed reinforcement and was associated with a black line on a white background (S2). The major results showed that (a) decremental gradients were obtained around the stimulus associated with the delayed reinforcement component when S1 was associated with extinction, but that incremental gradients were obtained when S1 was associated with immediate reinforcement, (b) the subjects' pretraining did not affect the generalization gradients if sufficient training on the terminal multiple schedule was provided, and (c) changing the S1 schedule from immediate reinforcement to extinction produced behavioral contrast if reinforcement was delayed for 10 sec during S2, but not if it was delayed for 20 sec.     

Choice and amount of reinforcement in rats

Rats were exposed to concurrent-chains schedules in which the terminal links were equal, fixed-interval (FI) schedules terminating in one or a varying number of food pellets. In most rats, choice proportions for the larger reinforcer increased with increases in reinforcer amount (e.g., from one to five food pellets). When log response ratios were plotted against log reinforcer amount ratios, the results indicated that the effects of reinforcer amount depended on the length of fixed-interval terminal links, by showing that rats undermatched their response ratios to reinforcer amount ratios with the shorter terminal links (FI 5 s, Experiment 1), whereas they overmatched with the longer terminal links (FI 20 s, Experiment 2). These results demonstrated that the manipulation of FI terminal-link schedules affected the sensitivity of choice to reinforcer amount, and are consistent with the previous findings that choice proportions for the larger of two reinforcers (one vs three food pellets) increased with increases in the length of FI terminal-link schedules.     

Cerebral lateralization for speech in deaf and normal children

The cerebral lateralization pattern for speech production in normal hearing and congenitally deaf children was studied using the dual-task paradigm. Performance under the verbal task conditions showed predicted left hemispheric dominance for speech production in the normal hearing children. No developmental trends in asymmetry were found, suggesting that speech lateralization is present in normal 3-year-old children. These data support the developmental invariance hypothesis of cerebral organization. Deaf children showed more symmetrical patterns of cerebral control for speech production. No developmental trends in functional brain organization were observed among prepubescent deaf children.     

An empirical investigation of self-esteem as a composite construct

Three measures of chronic self-esteem, plus four measures developed to assess situational components of self-esteem (task-specific self-esteem and social self-esteem), were administered to 238 undergraduates at a large, urban university and a community college in the southeastern United States. Evidence for a composite construct of self-esteem was found. Results also indicate task-specific self-esteem correlates as high as .42 (p < .01) with chronic self-esteem and as high as .76 (p < .01) with social self-esteem. Task-specific self-esteem was found to be a better predictor of grade point average than chronic or social self-esteem. Suggestions are made for further research on the situational components of self-esteem to extend current findings.     

Helping as a function of empathic responses and sociopathy

The present study reports two experiments which investigated helping as a function of empathic anxiety (anxiety in response to modeled distress) and individual differences in sociopathic tendencies. The first experiment concerned the effects of empathic anxiety, sociopathy, and perceived similarity/dissimilarity to a distressed person on helping. As predicted, subjects who experienced high levels of empathic anxiety helped more than subjects who experienced low levels of empathic anxiety. High sociopathic subjects experienced lower levels of empathic anxiety and helped less than did low sociopathic subjects. However, a path analysis disclosed that sociopathy's relationship to helping was not due to (or mediated by) empathic anxiety. The similarity manipulation did not influence empathic anxiety or helping. In the second experiment, subjects were classified as primary or secondary sociopaths (based on their levels of trait anxiety). As in the first experiment, empathic anxiety and sociopathy were significantly related to helping. Primary sociopaths displayed less empathic anxiety than secondary sociopaths, but the two groups did not differ in their willingness to help. Thus, in neither study could the sociopath's behavior be explained by empathic anxiety. The discussion concerned empathy as a mediational variable in helping and the role of personality variables in helping. A post hoc explanation of the sociopath's behavior, based on Schwartz' theory of the characteristics of helpers, was proposed.     

Response elimination in rats with schedules of omission training, including yoked and response-independent reinforcement comparisons

After rats were trained to lever press, response elimination began with factorial combinations of fixed vs variable and adjusting vs constant omission training schedules. A time interval scheduling reinforcement remained the same in a constant schedule, and its length was increased as response rate declined in the adjusting schedule. A variable time (VT) response-independent reinforcement schedule followed response elimination to test the durability of response cessation. Experiment I included groups whose reinforcement was yoked to that received by the omission schedule groups. Rate of response elimination was faster with an adjusting than a constant schedule, and slightly faster with a variable than a fixed schedule. There were no significant differences in rate of response elimination between omission schedule and yoked groups. Shorter delay of reinforcement tended to increase rate of response elimination. In the subsequent VT durability test all groups displayed near-zero response rates. In Experiment II adjusting fixed and variable omission schedules, including yoked groups, were compared with fixed time (FT) and VT reinforcement schedules. Response elimination was slower in the FT and VT groups, and they responded more in a subsequent VT durability test. It was concluded that differential reinforcement of other behavior fails to account for these omission training effects, and suggestions were made for an analysis based on the correlation between response and reinforcement rate.     

Factor structure of the McCarthy scales for school-age children with low GCIs

This study aimed to cross-validate the factor analysis of the McCarthy Scales and to determine the construct validity of these scales for children who score one standard deviation below the normative mean on general cognitive ability. The sample was comprised of 77 children aged 6 to $\text{8}\text{1}\text{2}$ with a mean General Cognitive Index (GCI) of 61.6. Principal factor analysis produced four meaningful factors which corresponded closely to four of the scales on McCarthy's battery. The present findings discourage the interpretation of the Quantitative Scale for school-age children with GCIs below 84. Other implications of the results for the interpretation of McCarthy profiles for low-scoring school-aged children are discussed.