Choice as a function of local versus molar reinforcement contingencies.

Rats were trained on a discrete-trial probability learning task. In Experiment 1, the molar reinforcement probabilities for the two response alternatives were equal, and the local contingencies of reinforcement differentially reinforced a win-stay, lose-shift response pattern. The win-stay portion was learned substantially more easily and appeared from the outset of training, suggesting that its occurrence did not depend upon discrimination of the local contingencies but rather only upon simple strengthening effects of individual reinforcements. Control by both types of local contingencies decreased with increases in the intertrial interval, although some control remained with intertrial intervals as long as 30 s. In Experiment 2, the local contingencies always favored win-shift and lose-shift response patterns but were asymmetrical for the two responses, causing the molar reinforcement rates for the two responses to differ. Some learning of the alternation pattern occurred with short intertrial intervals, although win-stay behavior occurred for some subjects. The local reinforcement contingencies were discriminated poorly with longer intertrial intervals. In the absence of control by the local contingencies, choice proportion was determined by the molar contingencies, as indicated by high exponent values for the generalized matching law with long intertrial intervals, and lower values with short intertrial intervals. The results show that when molar contingencies of reinforcement and local contingencies are in opposition, both may have independent roles. Control by molar contingencies cannot generally be explained by local contingencies.     

Stimulus control of Pavlovian facilitation

Two experiments were conducted using an autoshaping procedure with pigeons to examine whether dimensional stimulus control by a Pavlovian facilitator parallels the control established following operant discrimination training. Facilitation training consisted of the presentation of a black vertical line on a white background as the B stimulus in a feature-positive discrimination in which the A stimulus (white keylight) was followed by grain presentation only if preceded by B. In this way, B facilitates or sets the occasion for pecking at A. Subsequent testing for generalization along the line-orientation dimension produced decremental gradients when the facilitation paradigm incorporated an explicit feature-negative stimulus (B−). These results parallel the decremental control obtained following operant discrimination training and suggest that Pavlovian facilitators and instrumental discriminative stimuli are functionally equivalent.     

Accuracy of weightbearing at three target levels during bilateral upright stance in patients with neuropathic feet and control subjects

The purposes of this study were to (1) describe errors in weightbearing at three target levels for patients with neuropathic feet and control subjects, (2) compare the absolute errors at the three target levels between groups, and (3) identify predictor variables of errors in weightbearing by the neuropathic group. The groups of 26 subjects were matched for age and height. Weightbearing was measured with digital scales while subjects attempted to adjust their weight through a designated lower extremity to each target level (25, 50, and 75% of body weight). Analysis of variance indicated no significant difference in the percentage weightbearing between groups at the three target levels. There was a significant difference in errors made in weightbearing by the groups at the three target levels. Mean errors ranged from 8.5 to 9.7% for the neuropathic group and from 2.4 to 6.6% for the control group. The findings cast doubt on the utility (in the absence of feedback) of requesting individuals, particularly those with neuropathic feet, to weightbear at specific target levels.     

Comparison of two locus of control scales in predicting relapse in an alcoholic population

A 3-mo. follow-up was made of 64 male veterans who were discharged from a 21-day Alcohol Detoxification Treatment Program at the Veterans Affairs Medical Center at Lyons, NJ. Scores on the Rotter I-E and Alcohol Responsibility Scales were significantly correlated with tendencies toward a more external direction among the 13% who relapsed, significant on the I-E scale and nonsignificant on the Alcohol Responsibility Scale. When tests were compared as possible predictor variables of alcoholic relapse, the difference in favor of the I-E scale was statistically nonsignificant.     

Subliminal stimulation, choice behavior and some personality correlates of subliminal sensitivity

The aim of this study was to investigate the possible relations between specific personality variables and the effect of subliminal stimulation on choice behavior. It was hypothesized that subjects with low anxiety, less neuroticism, and external locus of control and the trait of extraversion would be more susceptible to subliminal stimulation. 38 undergraduate students were exposed to subliminal messages urging them to choose symbols instead of numbers or letters. Analysis showed that subliminal stimulation did not generate a preference for symbols over numbers or letters. No support was observed for the hypothesis of an association between susceptibility and personality variables. These results may be explained in terms of symbol choice being a neutral message that did not relate to the subjects' needs and motivation.     

Developmental perspectives on the localization and detection of auditory signals

Responsiveness of 1-, 3-, and 5-year-old children and adults to octave-band noises at .4 and 10 kHz was assessed with a go/no-go version of visual reinforcement audiometry (VRA) (Moore, Thompson, & Thompson, 1975) and a two-alternative, forced-choice version (Suzuki & Ogiba, 1961; Trehub, Schneider, & Endman, 1980). Infants performed better on the two-alternative, forced-choice version in quiet and in noisy backgrounds, and adults performed better on the two-alternative, forced-choice version in quiet but not in noisy backgrounds. Performance on the two tasks was essentially equivalent for 3- and 5-year-old children. Superior performance on two-alternative VRA over go/no-go may be due to lesser cognitive demands in the case of infants and to the engagement of superior decision strategies in the case of adults.     

On the scope of alcohol expectancy research: remaining issues of measurement and meaning

An article by Leigh (1989d) examined certain substantive and measurement-related limitations of research on alcohol outcome expectancies. Leigh (1989d) criticized research in this field on both conceptual and methodological grounds and speculated on future theoretical directions for research in the field. In their response, Goldman, Brown, Christiansen, and Smith (1991) contended that Leigh's critique is faulty in important respects. However, some of their points are based on misinterpretations of Leigh's comments, and they appear to have insufficient appreciation of conditions necessary for comprehensive measurement validation and for meaningful application of theories of memory to alcohol expectancy research. Despite the limitations of expectancy research, exciting avenues exist for further work.     

Neuropsychological correlates of hypertension: review and methodologic considerations.

Essential hypertension is a chronic disorder having many potential physical and behavioral sequelae. This article evaluates the impact of hypertension on neuropsychological test performance. First, cross-sectional and longitudinal studies that examine the neuropsychological correlates of hypertension are reviewed. In general, hypertensives are found to perform more poorly than normotensives, particularly on tests of memory, attention, and abstract reasoning, and less consistently on tests of perception, constructional ability, mental flexibility, and psychomotor speed. Next, the influence of variables that may moderate relationships between hypertension and neuropsychological performance--such as age, education, and medication usage--are examined. Finally, potential mechanisms, both physiological and psychological, underlying associations between hypertension and neuropsychological performance are discussed.