Behavioral contrast in fixed-interval components: effects of extinction-component duration.

Seven albino rats were exposed to a multiple schedule of reinforcement in which the two components (fixed interval and extinction) alternated such that a presentation of the extinction component followed each fixed-interval reinforcement. In baseline sessions, the duration of the extinction component was constant and always one-third of the fixed-interval value. Probe sessions contained a probe segment in which the duration of the extinction component was increased; the response rate in fixed-interval components during the probe segment was compared with the response rate in the segments preceding and following the probe. The effect of increasing the duration of the extinction component was studied under three values of fixed interval: 30 s, 120 s, and 18 s, in three successive conditions. Response rate within fixed intervals was a direct function of duration of the extinction component. Pausing at the beginning of the fixed interval decreased as extinction duration increased. These effects were larger and more consistent for the shorter fixed-interval values (18 s and 30 s). These results indicate a functional relation between relative component duration and responding. For the component providing more frequent reinforcement, this could be stated as an inverse relationship between relative component duration and response rate. This relation is similar to findings regarding the ratio of trial and intertrial duration in Pavlovian conditioning procedures, and suggests that behavioral contrast may be related to Pavlovian contingencies underlying the multiple schedule.     

Social and emotional loneliness: an examination of Weiss's typology of loneliness

This study examined Weiss' conceptualization of social and emotional loneliness. Using data from an extensive survey of undergraduate and graduate students at the University of Iowa, we measured social and emotional loneliness, students' affective and behavioral reactions to loneliness, students' social relationships, and their judgments of the degree to which their relationships supply the six social provisions described by Weiss. As expected, we found differences in the subjective experiences of social and emotional loneliness, although both forms of loneliness were also characterized by a common core of experiences. The results generally supported Weiss's ideas concerning the determinants of social and emotional loneliness. Predictions concerning the affective and behavioral consequences associated with each type of loneliness, however, were only partly supported, although the two forms of loneliness were associated with different affective reactions and coping behaviors. The implications of these findings for Weiss's typology of loneliness are discussed.     

SOCIOBIOLOGY AND ITS THEOLOGICAL IMPLICATIONS

Abstract. The broad character of the arguments used by sociobiologists is assessed, particularly in relation to criticisms coming from anthropology. The implications of sociobiology for theology are developed with respect to the general impact of evolutionary ideas, the reductionist assumptions of sociobiologists, whether or not "survival" can be a value, and more holistic accounts of the physical and biological grounding of the mental and spiritual lives of human beings.     

THERMODYNAMICS AND LIFE

Abstract. The basic features of thermodynamics as the "science of the possible" are outlined with a special emphasis on the role of the concept of entropy as a measure of irreversibility in natural processes and its relation to "order," precisely defined. Natural processes may lead to an increase in complexity, and this concept has a subtle relationship to those of order, organization, and information. These concepts are analyzed with respect to their relation to biological evolution, together with other ways of attempting to quantify it. Thermodynamic interpretations of evolution are described and critically compared, and the significance of dissipative structures, of "order through fluctuations," is emphasized in relation both to the evolutionary succession of temporarily stable forms and to kinetic mechanisms producing new patterns.     

Factor analysis by generalized least squares

Aitken's generalized least squares (GLS) principle, with the inverse of the observed variance-covariance matrix as a weight matrix, is applied to estimate the factor analysis model in the exploratory (unrestricted) case. It is shown that the GLS estimates are seale free and asymptotically efficient. The estimates are computed by a rapidly converging Newton-Raphson procedure. A new technique is used to deal with Heywood cases effectively.The work on this project was done when the first author was Research Statistician at Educational Testing Service, Princeton, N. J. The second author was in part supported by a grant from the Research Committee of the University of Wisconsin Graduate School. The authors wish to thank Michael Browne for many helpful comments and Marielle van Thillo for valuable assistance in the numerical computations.     

Limits on the applicability of signal detection theories

Two auditory signals were presented in random sequences in which the more intense signal came on.2, .5, or.8a/the trials. Each trial began with an intermediate tone which was identified in the instructions as either the standard for comparison or simply as a warning tone. Half the Os were instructed to discriminate whether the signal was “louder” or “softer” than the standard, the other half to recognize which signal had been presented. For both discrimination and recognition tasks, the total proportion of ldlouder” judgments was independent of the presentation probabilities, accuracy for each signal varying inversely with its probability of presentation. These results suggest strict limitations on the response optimization posited by theories of signal detection.     

Similarity of cardiac CR forms in the rhesus monkey during several experimental procedures

Cardiac rates of rhesus monkeys were observed in a variety of different conditioning procedures, each of which involved a visual stimulus (CS) followed by an electric shock (US). With a 30-sec CS, cardiac rate accelerated rapidly after CS onset, reached a maximum in the middle of CS, and decelerated thereafter, with a terminal CS rate often at the level of, or below, pre-CS levels. A similar biphasic cardiac rate response in CS was also observed under subsequent exposure to intermittent pairings of CS and US, avoidance of US, response-produced termination of US, and when CS-US pairings were superimposed upon an avoidance baseline, even when CS duration was varied from 12 to 60 seconds. The unusual regularity of cardiac rate responses in several different procedures may result from one or more of these factors: (a) characteristics of the rhesus monkey, (b) initial exposure to Pavlovian conditioning, or (c) the uniformity of measurement of cardiac rate employed in this study.     

Peer Relationships and Male Academic Achievement: A Review and Suggested Clarification

Earlier reviews of the research have reached conflicting conclusions about the relationship between social behavior and academic achievement. A brief but comprehensive review is presented. It is suggested that there is greater consistency in this research area than has previously been noted. When the research is categorized according to sample age level, it is found among younger subjects that high achievers tend to be more socially active than low achievers, while among college-age students, low achievers tend to be the more socially active. Questions are raised which future research might investigate.