Concurrent fixed-interval variable-ratio schedules and the matching relation

Five rats responded under concurrent fixed-interval variable-ratio schedules of food reinforcement. Fixed-interval values ranged from 50-seconds to 300-seconds and variable-ratio values ranged from 30 to 360; a five-second changeover delay was in effect throughout the experiment. The relations between reinforcement ratios obtained from the two schedules and the ratios of responses and time spent on the schedules were described by Baum's (1974) generalized matching equation. All subjects undermatched both response and time ratios to reinforcement ratios, and all subjects displayed systematic bias in favor of the variable-ratio schedules. Response ratios undermatched reinforcement ratios less than did time ratios, but response ratios produced greater bias than did time ratios for every subject and for the group as a whole. Local rates of responding were generally higher on the variable-ratio than on the fixed-interval schedules. When responding was maintained by both schedules, a period of no responding on either schedule immediately after fixed-interval reinforcement typically was followed by high-rate responding on the variable-ratio schedule. At short fixed-interval values, when a changeover to the fixed-interval schedule was made, responding usually continued until fixed-interval reinforcement was obtained; at longer values, a changeover back to the variable-ratio schedule usually occurred when fixed-interval reinforcement was not forthcoming within a few seconds, and responding then alternated between the two schedules every few seconds until fixed-interval reinforcement finally was obtained.     

Factor structure of the Tennessee Self-Concept Scale for an institutionalized, disabled population

Separate factor analyses of responses to the Tennessee Self-concept Scale using item and scale data are reported for a sample of 255 disabled veterans. A global self-satisfaction factor and several subsidiary factors roughly approximate the external dimension of the scale. The internal dimension interacts with the external one in defining several factors but does not emerge as an independent dimension. Scale data yield a self-esteem factor incorporating both external and internal scales and a self-concept conflict-integration factor. The evidence supports the external dimension more than the internal dimension. The findings are consistent with previous studies that have not validated the two-dimensional design of the scale.     

Some implications of Jewish marriage philosophy for marital breakdown

A clarification of some of the roots of marital breakdown is sought through examining the love relationship in Viktor Frankl's logotherapy and its theological counterparts in Judaism. Frankl's implicit ethic of self-transcendence coincides with Judaism's view of the married state as shared destiny. Together these call into question the ethic of self-fulfillment which appears to underlie much marital distress.Dr. Bulka is Rabbi of Congregation Machzikei Hadas in Ottawa, Ontario, and Editor of theJournal of Psychology and Judaism. His address is: 1747 Featherston Drive, Ottawa, Ontario, Canada K1H 6P4.     

Constrained least squares estimators of oblique common factors

An expression is given for weighted least squares estimators of oblique common factors, constrained to have the same covariance matrix as the factors they estimate. It is shown that if as in exploratory factor analysis, the common factors are obtained by oblique transformation from the Lawley-Rao basis, the constrained estimators are given by the same transformation. Finally a proof of uniqueness is given.The research reported in this paper was partly supported by Natural Sciences and Engineering Research Council Grant No. A6346.     

Feedback interventions and driving speed: A parametric and comparative analysis

Five experiments were conducted to assess the effects of several variables on the efficacy of feedback in reducing driving speed. Experiment 1 systematically varied the criterion used to define speeding, and results showed that the use of a lenient criterion (20 km/hr over the speed limit), which allowed for the posting of high percentages of drivers not speeding, was more effective in reducing speeding than the use of a stringent criterion (10 km/hr over the speed limit). In Experiment 2 an analysis revealed that posting feedback reduced speeding on a limited access highway and the effects persisted to some degree up to 6 km. Experiments 3 and 4 compared the effectiveness of an unmanned parked police vehicle (Experiment 3) and a police air patrol speeding program (Experiment 4) with the feedback sign and determined whether the presence of either of these enforcement variables could potentiate the efficacy of the sign. The results of both experiments demonstrated that although the two enforcement programs initially produced larger effects than the feedback sign, the magnitude of their effect attenuated over time. Experiment 5 compared the effectiveness of a traditional enforcement program with a warning program which included handing out a flier providing feedback on the number and types of accidents occuring on the road during the past year. This experiment demonstrated that the warning program produced a marked reduction in speeding and the traditional enforcement program did not. Furthermore, the warning program and a feedback sign together produced an even greater reduction in speeding than either alone.     

A generalization of comparative probability on finite sets

Let ? be a binary relation on a finite algebra $\text{A}$ of events A, B,…, where A ? B is interpreted as “A is more probable than B.” Conventional subjective probability is concerned with the existence of a probability measure P on $\text{A}$ that agrees with ? in the sense that A ? B ? P(A) > P(B). Because evidence suggests that some people's comparative probability judgments do not admit an agreeing probability measure, this paper explores a more flexible scheme for representing ? numerically. The new representation has A ? B ? p(A, B) > 0, where p is a monotonic and normalized skew-symmetric function on $\text{A}$ × $\text{A}$ that replaces P's additivity by a conditional additivity property. Conditional additivity says that $\text{p(A ? B, C) + p(?, C) = p(A, C) + p(B, C)}$ whenever A and B are disjoint. The paper examines consequences of this representation, presents examples of ? that it accommodates but which violate the conventional representation, formulates axioms for ? on $\text{A}$ that are necessary and sufficient for the representation, and discusses specializations in which p in separable in its arguments.     

Motor strategies in lifting movements: a comparison of adult and child performance

The experiment compares the performances of children six to nine years old and adults in a simple, monoarticular lifting task. Overt behaviors, as described by the kinematic features of the movement, do not differ qualitatively in the two groups. The patterns of motor commands, as expressed by the electromyographic recordings, are however strikingly different. Adults plan the movement with a careful balance between agonist muscle activity and passive, viscoelastic forces, whereas children use both agonist and antagonist active forces. It is argued that the motor strategy adopted by adults depends upon an internal representation of the properties of the motor system and of the size/weight covariation in natural objects, and that this representation is not yet fully developed at nine years of age.     

The development of walking: new findings and old assumptions

I have argued that a behavioral-cognitive perspective may shed light on some aspects of motor development generally, and unaided walking, specifically. Individual components of walking-stepping, standing, and placing, for example-are present at birth and can be maintained with practice. Moreover, consistent use can produce an earlier onset of unaided walking. Nonetheless, independent erect locomotion rarely occurs before about 9 months in most societies, implying that there is a maturational constraint. Independent research on changes in the quality of object use imply that the maturational limitation may be cognitive, in part. Changes in motor development-both the onset of unaided walking and the emergence of functional use-may be dictated by an underlying change in information processing ability. It is hypothesized that the infant's capacity to generate ideas or access different associations from memory rapidly may define the nature of this change. Improved access to memory may permit the necessary integrative capacity for balance and coordination to occur, thereby permitting unaided walking to develop. Weiss and Zelazo found that the capacity to perform two distinct actions in rapid succession in an independent environment-water-also appears to emerge from about 9 through 12 months. Not only may a cognitive change influence motor development, but mental and motor ability may develop asynchronously in some instances-a particularly important implication for developmental assessment. Procedures to distinguish information processing ability independent of gross and fine motor measures and productive language can lead to treatment that will reduce delays on conventional tests and contribute to the validity of this argument.