Memory storage and retrieval processes in category learning

The detailed course of learning is studied for categorization tasks defined by independent or contingent probability distributions over the features of category exemplars. College-age subjects viewed sequences of bar charts that simulated symptom patterns and responded to each chart with a recognition and a categorization judgment. Fuzzy, probabilistically defined categories were learned relatively rapidly when individual features were correlated with category assignment, more slowly when only patterns carried category information. Limits of performance were suboptimal, evidently because of capacity limitations on judgmental processes as well as limitations on memory. Categorization proved systematically related to feature and exemplar probabilities, under different circumstances, and to similarity among exemplars of categories. Unique retrieval cues for exemplar patterns facilitated recognition but entered into categorization only at retention intervals within the range of short-term memory. The findings are interpreted within the framework of a general array model that yields both exemplar-similarity and feature-frequency models as special cases and provides quantitative accounts of the course of learning in each of the categorization tasks studied.     

On the Dialectics of Liberation Theology

In this article the author argues that no coherent theology of liberation is possible if that theory's rational grounding of historical analysis is based on the dialectics of scientific socialism. After a brief outline of the affinities between the Marxist and Christian salvation histories, the author discusses the scientific status of the dialectical laws, highlights the role that dialectics play in the theology of liberation developed by Gustavo Gutierrez (1973), and reflects on the future development of liberation theology.     

Disturbances in exploratory behavior and functional recovery in the Y and radial mazes following dopamine depletion of the lateral septum

The effects of 6-hydroxydopamine (6-OHDA) injected into the lateral septum in rats were investigated for spontaneous alternation behavior in a Y maze and for spatially oriented behavior in an 8-arm radial maze. The performance of the animals in these tests was assessed under two physiological states, food-satiated and food-deprived. The selective depletion of septal dopaminergic concentrations leads to behavioral disturbances in both the Y and the radial mazes. These deficits disappeared when the animals with 6-OHDA lesions were food-deprived. These results confirm other studies from our laboratory and support two conclusions. First, lesions of dopaminergic neurons lead to behavioral impairments which resemble those found after the total lesion of the structure they innervate. Second, these behavioral impairments are responsive to therapeutic treatments, manipulations of the internal or external environment, or the level of arousal, since under certain conditions a recovery of function can occur in the absence of dopaminergic neurons. These two points provide additional support for a nonspecific role for the dopaminergic neurons originating in the ventral tegmental area. These neurons could have a permissive role in the functioning of the forebrain structures they innervate.     

Behavioral effects of sucrose on preschool children

Despite speculation that sucrose consumption affects behavior, little empirical information is available. Accordingly, this study investigated the effect of sucrose consumption on the behavior of eight preschool children. Children were tested individually using a double-blind, crossover design. On separate mornings each child received 6 ounces of juice, sweetened on one morning with sucrose and on the other with an artificial sweetener. Children were observed for 90 minutes following the drinks, alternating between 15-minute sessions of work on structured tasks and 15-minute sessions of free play. Following the sucrose drink the children showed a decrement in performance in the structured testing situation, and they demonstrated more inappropriate behavior during free play. These differences in behavior were most pronounced approximately 45 to 60 minutes after the drinks. Thus, the study provides objective evidence in young children of a rather subtle, yet significant, time-dependent behavior effect of sucrose ingestion.This research was funded in part by grants from the General Research Grants Committee, University Hospital, Boston University Medical Center, and from the University of Connecticut Research Foundation. The project was conducted at the Clinical Research Center, Massachusetts Institute of Technology (National Institute of Health/General Clinical Research Center Grant 5M01-RR00088-20). We would like to express our appreciation to the many staff members of the Clinical Research Center for their extensive cooperation in helping us to plan and carry out this study, and to the director and staff of Technology Children's Center for their assistance in helping us to reach interested families. We also would like to thank the parents and children who participated in the study. Portions of this paper were presented at the annual meeting of the American Psychological Association, Toronto, August 1984.     

Effects of treatments and their outcomes on peer perceptions of a hyperactive child

In an exploration of the social impacts of treatments for hyperactivity, two age groups (kindergarteners and first-graders vs. fourth- and fifth-graders) heard about a hyperactive child whose problem was treated either by an internal and controllable means (effort) or by an external and uncontrollable means (medication) and whose behavior either did or did not improve. The attributions and affective responses of both age groups were influenced by both the nature and the effectiveness of treatment, and there was only weak support for the hypothesis that younger children are more influenced by treatment outcome than older children are. However, older children, conforming to attribution theory predictions, held target children more accountabe for the success or failure of their own efforts than for the outcomes of medication, particularly valuing the child whose own efforts succeeded. By contrast, young children judged the child whose efforts failed as more worthy of pride and more likable than the child whose medication failed. Implications for peer acceptance of hyperactive children over the childhood years are discussed.Portions of this paper were presented at the annual meeting of the Southeastern Psychological Association, Atlanta, March 1985. Thanks are extended to the staff and students of the Model Laboratory School.     

Health as a value: methodological and theoretical considerations

The concept of value placed on health is very important in several different theoretical approaches to the study of health behavior. In practice, however, health value is generally assumed to be universally high rather than being directly measured. If this assumption is incorrect, then theories that include health value have rarely been adequately tested. This paper presents a short 4-item Likert scale designed to measure the value placed on health. Norms from the utilization of this scale in five different samples are presented. Health value is found to increase with age among girls, but the increase apparently stops by late adolescence, before full adult levels of health value are achieved. Middle-aged women place a higher value on health than do middle-aged men, although no comparable sex difference appears in a sample of undergraduates. Consistent with theoretical predictions, both health locus of control beliefs and beliefs in the efficacy of certain preventive health behaviors correlate more highly with the performance of those same behaviors 5 to 9 months later among respondents who place a high value of health relative to those who do not value health so highly. However, this interaction is found only when it can be safely assumed that health is the primary value underlying the behavior. The importance of considering a variety of values in addition to health as possible motivators of preventive health behavior is stressed.     

A Comparison of Two Cases of Counseling with the Same Counselor

Process analyses revealed that interpretations and exploration of feelings were helpful across two cases. Other interventions were helpful for one case but not the other.     

A post hoc correction procedure for systematic errors in time-sampling duration estimates

Numerous previous studies have shown that partial-interval sampling in direct observation systematically overestimates duration and underestimates frequency. Whole-interval sampling systematically underestimates both duration and frequency. This paper presents a post hoc method through which the systematic errors in duration estimates in partial-interval sampling and whole-interval sampling can be minimized.     

Psychopathology subtypes and symptom correlates among former prisoners of war

Psychopathology and symptom patterns were studied in 60 former prisoners-of-war (POWs) by administering standardized tests including the Minnesota Multiphasic Personality Inventory (MMPI), an adjustment problem checklist, and a structured clinical interview. Most POWs showed marked psychological impairment, but modal profile analysis identified two prototypic MMPI patterns, which differed in pervasiveness and type of psychopathology. Profile subtypes were defined by unique clusters of clinical symptoms and differed in confinement stress severity. The typology of symptoms argues against a homogeneous conceptualization of stress-induced disorders and suggests the need for definition of the severity and subtype of stress phenomena and individual difference factors in responding to trauma.