Concurrent schedules: Spatial separation of response alternatives

Four pigeons were exposed to independent concurrent variable-interval 20-second variable-interval 60-second schedules of reinforcement. A transparent partition was inserted midway between the two response keys. The length of the partition was systematically manipulated. Increasing partition length produced a decrease in changeover rate in Experiment 1. Over-matching was observed with a partition length of 20 centimeters. In Experiment 2 a four-second limited hold was added to the schedules. Increasing partition length produced a decrease in changeover rate that exceeded the decrease observed in Experiment 1. This manipulation produced nearly exclusive choice of the variable-interval 20-second component. The present results, together with results obtained in related research, suggest that deviation from matching is a function of procedural variables that determine the consequences of a changeover response.     

On the psychometric properties of the Maudsley Marital Questionnaire (MMQ): Evaluation of self-ratings in distressed and ‘normal’ volunteer couples based on the dutch version

The current preliminary study presents data on reliability and validity of the Maudsley Marital Questionnaire (MMQ), a short 20-item scale which was designed to assess degree of favourableness of attitude towards one's own marriage. The MMQ contains three scales related to marital, sexual and general life adjustment, whose composition was initially based on those of analogue scales of the Structured and Scaled Interview to Assess Maladjustment (SSIAM). In addition to providing substantial support for an almost perfect similarity between hypothetical and empirical MMQ dimensional representations, findings, based on self-ratings of 125 volunteer couples from the community and 50 distressed couples, demonstrated that the MMQ scales have high internal consistency, sufficient test-retest reliability and validity and are only slightly correlated with social desirability.     

Color-object interference: Further tests of an executive control account

Young children are slower in naming the color of a meaningful picture than in naming the color of an abstract form (Stroop-like color-object interference). The current experiments tested an executive control account of this phenomenon. First, color-object interference was observed in 6- and 8-year-olds but not in 12- and 16-year-olds (Experiment 1). Second, meaningful pictures did not interfere in 5- to 7-year-olds’ manual sorting of objects on the basis of color (Experiment 2) or in their naming the number of colored objects in the display, that is, subitizing (Experiment 3). These findings provide support for the view that color-object interference results from the children’s immature inhibition of the prepotent but irrelevant task of object naming.     

Cohort differences in Big Five personality factors over a period of 25 years

The notion of personality traits implies a certain degree of stability in the life span of an individual. But what about generational effects? Are there generational changes in the distribution or structure of personality traits? This article examines cohort changes on the Big Five personality factors Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness to Experience, among first-year psychology students in The Netherlands, ages 18 to 25 years, between 1982 and 2007. Because measurement invariance of a personality test is essential for a sound interpretation of cohort differences in personality, we first assessed measurement invariance with respect to cohort for males and females separately on the Big Five personality factors, as measured by the Dutch instrument Five Personality Factors Test. Results identified 11 (females) and 2 (males) biased items with respect to cohort, out of a total of 70 items. Analyzing the unbiased items, results indicated small linear increases over time in Extraversion, Agreeableness, and Conscientiousness and small linear decreases over time in Neuroticism. No clear patterns were found on the Openness to Experience factor. Secondary analyses on students from 1971 to 2007 of females and males of different ages together revealed linear trends comparable to those in the main analyses among young adults between 1982 onward. The results imply that the broad sociocultural context may affect personality factors.     

A computer-based system providing pictorial instructions and prompts to promote task performance in persons with severe developmental disabilities

This study was aimed at assessing a new computer-based system to promote task performance in three adults with severe developmental disabilities. The new system, which was small and battery powered, could provide auditory and vibratory prompts in addition to pictorial instructions concerning the task steps. To control for the effects of the computer-based system, the subjects were also exposed to a card system. The results showed that the subjects had a significantly higher level of correct performance on the tasks presented with the computer-based system than on the tasks presented with the card system. Two of the subjects, moreover, seemed to prefer the computer-based system to the card system. © 1998 John Wiley & Sons, Ltd.     

Personality and team performance: a meta‐analysis

Using a meta‐analytical procedure, the relationship between team composition in terms of the Big‐Five personality traits (trait elevation and variability) and team performance were researched. The number of teams upon which analyses were performed ranged from 106 to 527. For the total sample, significant effects were found for elevation in agreeableness (ρ = 0.24) and conscientiousness (ρ = 0.20), and for variability in agreeableness (ρ = ?0.12) and conscientiousness (ρ = ?0.24). Moderation by type of team was tested for professional teams versus student teams. Moderation results for agreeableness and conscientiousness were in line with the total sample results. However, student and professional teams differed in effects for emotional stability and openness to experience. Based on these results, suggestions for future team composition research are presented. Copyright © 2006 John Wiley & Sons, Ltd.     

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.

     

Concurrent schedules: Transient-state changeover behaviour

Ten pigeons responded in a two-alternative continuous-choice situation. Rein-forcers were programmed by a single variable-interval 30-sec schedule. The proportion of reinforcers assigned to one alternative was either 0.67 or 0.50 in different conditions. The changes in local changeover rates following changes of conditions were adequately described by an exponential function. This result can be explained by a model of changeover behaviour proposed by Myerson and Miezin (1980), if a simplifying assumption is made about reinforcement rates as controlling variables. A modification of the Myerson and Miezin model that accounts for the exponential function but does not make assumptions about reinforcement rates as controlling variables is presented.     

BRIEF REPORT: ENABLING BLIND PERSONS WITH SEVERE OR PROFOUND MENTAL RETARDATION TO OPERATE AN ACOUSTIC ORIENTATION SYSTEM INDEPENDENTLY

The aim of this study was to assess new technology for enabling two blind persons affected by severe or profound mental retardation to operate an acoustic orientation system independently. By operating this system, the subjects could move to different activity destinations within an occupational setting and carry out activities free from external assistance. The results showed that both subjects learned to operate the system on their own. The high level of independence they achieved is reviewed in relation to the new technology and the simplified responding it requires     

An analysis of emergent simple discrimination in children

In Experiment 1 eight five-year-old children received an arbitrary matching-to-sample task with sample stimuli A1 and A2 and comparison stimuli B1 and B2. This task was mixed with a simple, two-choice discrimination task with stimuli A1 and A2. In subsequent tests with B1 and B2 presented alone, the number of responses to B1 was greater when it had been paired with the correct stimulus of the simple discrimination task than when it had been paired with the incorrect stimulus. In Experiment 2 incorrect comparisons were omitted during the matching-to-sample task. Eight children were taught to point to either A1 or A2 first, and to either B1 or B2 second. Eight other children were taught to point to either B1 or B2 first, and to either A1 or A2 second. The effect of Experiment 1 was replicated with the first but not with the second group. The results of both experiments suggest that the functions of S+ and S- in a simple discrimination task can transfer to test stimuli if the training stimuli precede the test stimuli during paired presentations.