Resistance to reinforcement change in multiple and concurrent schedules assessed in transition and at steady state

Behavioral momentum theory relates resistance to change of responding in a multiple-schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple-schedule conditions in which a variable-interval 40-s schedule arranged reinforcers for pecking in one component and a variable-interval 360-s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable-interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response-independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable-interval 80-s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short-term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short-term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.     

Biasing the pacemaker in the behavioral theory of timing

In the behavioral theory of timing, pacemaker rate is determined by overall rate of reinforcement. A two-alternative free-operant psychophysical procedure was employed to investigate whether pacemaker period was also sensitive to the differential rate of reinforcement. Responding on a left key during the first 25 s and on a right key during the second 25 s of a 50-s trial was reinforced at variable intervals, and variable-interval schedule values during the two halves of the trials were varied systematically. Responding on the right key during the first 25 s and on the left key during the second 25 s was not reinforced. Estimates of pacemaker period were derived from fits of a function predicted by the behavioral theory of timing to right-key response proportions in consecutive 5-s bins of the 50-s trial. Estimates of pacemaker period were shortest when the differential reinforcer rate most strongly favored right-key responses, and were longest when the differential reinforcer rate most strongly favored left-key responses. The results were consistent with the conclusion that pacemaker rate is influenced by relative reinforcer rate.     

An extension of the concept of specific objectivity

Comparisons of subjects are specifically objective if they do not depend on the items involved. Such comparisons are not restricted to the 1-parameter logistic latent trait model, but may also be defined within ordinal independence models and even within the 2-parameter logistic model.     

Risk perception and the location of a repository for spent nuclear fuel

This study investigates lay people's reactions to a repository for nuclear waste. Risk perception is seen as a complex concept, comprising both affective and cognitive components. Attitude towards nuclear power and trust in experts and authorities had a substantial impact on risk perception, while personal knowledge about nuclear waste disposal had no effect. Thus, the more positive one's attitude towards nuclear power is and the more trust one has in experts and authorities, the lower one's risk perception is. Also, reactions were expected to vary with distance between the home district and the location of a repository. These variations differed in nature for people with alternative levels of risk judgement. The distance between the home and a repository affected approval of the proposed site. Distance between home and repository also had an effect on risk feelings and somewhat less on beliefs about consequences. Estimated total risk was directly mediated by beliefs about consequences, but even more so by risk feelings. With regard to risk, one can conclude that it is important to make a distinction between an emotional and a cognitive component of risk perception.     

Content variations and performance on formal operational tasks by gender,social class and ability1

The role of task content, gender, social class and cognitive ability in performance on two formal operational tasks is explored in this paper. The participants were 110 Icelandic 12-year-olds, early and late developers, males and females from all socio-economic groups. Two tasks of variable isolation (the pendulum and three content versions of the “plant” problem) and two measures of volume conservation (three traditional tasks and three tasks formally identical whose content was pictorial social play) were presented individually in a school setting. The results suggest that content variations have differential consequences for the performance of early and late developers at age 12. Both the nature of logical competence and task content affect solutions, as suggested by Overton and collaborators in 1987. Some social class and gender differences were observed on two Piagetian tasks (pendulum and volume), which was reduced by changing the task content in the case of social class but not in that of gender. As the gender difference in volume conservation was not reflected ins chool achievement nor on other cognitive tasks it was interpreted as a gender bias. The findings are discussed in view of recent literature on the development of cognitive theory with increased emphasis on context and meaning in a post-structural intellectual climate.     

Toward culturally sensitive intervention with arab families in Israel

Over the past three decades, Arab society in Israel has been undergoing processes of transition. These processes are manifested by changes in the economy, education, the status of women, family structure, and by socio-cultural changes and transformations in patterns of coping with social problems. There is a serious lack of empirical research on the implications of this process for the value systems of Arab society and families in Israel and a dearth of relevant intervention-oriented literature. This article outlines the basic cultural values in the Arab society in Israel in an attempt to illuminate the relevance of these values for family structure and for direct interventions with Arab families in Israel.     

Psychological and educational characteristics of instruction for people with severe disabilities: Interacting systems of responding

This paper presents a behavioral model which proposes that operants are organized and regulated into systems of responding. Multi-operant theory proposes that operants are organized into response systems that interact to adapt behavior to the complexities of the environment. The operant is the interaction between behavior and the environment which includes the conditions under which responses may occur, the class of behavior that is likely to be effective in producing outcomes, and the antecedent conditions that define the context of behavior. A central feature of this theory is that operants within a repertoire are organized into regulated systems of responding. The mechanisms of regulation are themselves operants that are learned and controlled by processes that are the same as those that govern more overt behavior. Operants stand in relationship to each other in coordinated response systems with some operants directly affecting and organizing the performance of other operants. An important implication of the systemic nature of behavioral repertoires is that bringing some aspect of a behavior class under control of new variables may demonstrate a spread throughout the entire operant system depending on past histories linking the classes.deceased     

Brain dynamics,psychophysiological uncertainty and behavioral learning

The present paper takes a first step toward the integration of recent findings on brain dynamics and learning into established fields of psychophysiological science. Leading-edge studies of brain dynamics have shown that the brain manifests an inherent variability and that, when new stimuli (i.e., “problems”) are presented to the organism, brain chaos increases.     

My place,your place,and no place: Behavior settings as a risk factor for HIV-related injection practices of drug users in Baltimore,Maryland

Information is sparse on the social context of illicit drug injection behaviors and their relationship to HIV infection. This study examined relationships between injection settings, injecting with others, and HIV risk behaviors of sharing needles and not cleaning contaminated needles in a sample of 630 inner-city injecting drug users in Baltimore, MD. Through open-ended interviews, five primary settings of injection behavior were identified. These settings included one's own, friends' and mother's residence, shooting galleries, and semipublic areas. Most participants reported injecting in their own residence (92%) and friends' residence (86%) in the prior 6 months. In a multiple regression analysis, injecting at friends' residence, in shooting galleries, and in semipublic areas and frequency of injecting with others were significantly associated with frequency of sharing uncleaned needles, “slipping” (i.e., failure to disinfect shared needles), and not always cleaning used needles before injecting. Results suggest that interventions may benefit from targeting settings as well as behaviors to reduce the spread of HIV. This research was supported by grants DA04334, DA05911, DA06313, and DA08985 from the National Institute on Drug Abuse.     

COSMOLOGY FROM ALPHA TO OMEGA

Abstract. This paper focuses on four passages in the journey of the universe from beginning to end: its origin in the Big Bang, the production of heavy elements in first generation stars, the buzzing symphony of life on earth, and the distant future of the cosmos. As a physicist and a Christian theologian, I will ask how each of these passages casts light on the deepest questions of existence and our relation to God, and in turn how these questions are being explored through ongoing research into the interaction between Christian theology and the natural sciences.