A cost-benefit analysis of demand for food.

Laboratory studies of consumer demand theory require assumptions regarding the definition of price in the absence of a medium of exchange (money). In this study we test the proposition that the fundamental dimension of price is a cost-benefit ratio expressed as the effort expended per unit of food value consumed. Using rats as subjects, we tested the generality of this "unit price" concept by varying four dimensions of price: fixed-ratio schedule, number of food pellets per fixed-ratio completion, probability of reinforcement, and response lever weight or effort. Two levels of the last three factors were combined in a 2 x 2 x 2 design giving eight groups. Each group was studied under a series of six FR schedules. Using the nominal values of all factors to determine unit price, we found that grams of food consumed plotted as a function of unit price followed a single demand curve. Similarly, total work output (responses x effort) conformed to a single function when plotted in terms of unit price. These observations provided a template for interpreting the effects of biological factors, such as brain lesions or drugs, that might alter the cost-benefit ratio.     

Developmental psychology in the real world: A paradigm of parent education

Twenty years ago, William Kessen, Greta Fein and I developed and tested a model of parent education, a model which involved variation in curricular content, didactic approaches, and child outcomes–experimentally contrasted. Our experience yielded some valuable lessons about the extent to which researchers can influence parents' behaviour, and parents their children's development. In the present article I suggest that these lessons might be useful for researchers now as they were for us then. I present some observations about the research that developmental psychologists have done in the intervening two decades and suggest that we could learn much by using such a model of parent education to answer questions about the effets of parents' behaviour on children's development. Carefully done, parent education studies can yield valuable information about many of the questions raised in recent correlational research. Parent training research can suggest hypotheses that can be tested with data collected non-interventively and analysed in causal model analyses–and vice versa. What is more, because one reason for studying parent effects is so that we can offer guidance to parents about rearing their children, this design has a particular advantage; it is both the medium and the message.     

Cross-sex comparisons: A word of caution

A cross-sex difference on one variable is often hypothesized to be related to a gender difference on a second variable. However, caution should be exercised in making such comparative hypotheses. We gathered the expected and actual examination grades for 168 female and 163 male college students. As in prior research, males had higher expectancies than females (p<.05). But analysis of the intrasex regression equations indicated that the relationship of expectancies to performance was different for women than it was for men. Thus, a cross-sex difference in expectancies did not correspond to a parallel difference in grades. This finding highlights the potential hazards of making certain cross-sex comparisons, and we argue for more caution in their application.     

The Effectiveness of Encounter Groups: Implications of Research for Counselling Practice

In the past decade, encounter groups have become a widely recognised technique of intervention for counsellors. Empirical research on encounter groups is confusing. Trends in research are obscured by a diversity of definitions, methodologies and subjects. This review considers the most significant research on the effectiveness of encounter groups, focusing on positive and negative effects, leader behaviour, group characteristics, participant characteristics, and the maintenance of change. Conclusions are drawn relating the research to practice, with some suggested guidelines for use of encounter groups in counselling interventions.     

A preliminary study of Hare's “Research Scale for the Assessment of Psychopathy” in mentally-abnormal offenders

The abbreviated (15-item) version of Hare's Research Scale for the Assessment of Psychopathy (RSAP) was investigated in a sample of male admissions to Broadmoor Special Hospital (N = 50), along with five MMPI measures relevant to psychopathy (Impulsivity, Sociability, Psychopathic Deviate, Anxiety and Sociopathy). Patients were assigned to one of four clinical diagnostic groups: Personality Disorder, Mixed (personality disorder with schizophrenia), Schizophrenia and Affective Disorder. Results indicated that while both psychopathic groups (Mixed and Personality Disorder) showed high scores on almost all RSAP items, the Affective Disorder group showed low scores on almost all items. Results of a discriminant function analysis indicated that Hare's RSAP was superior to the MMPI measures at discriminating between psychopaths and non-psychopaths. Use of the discriminant function to re-allocate patients to criterion groups showed a high hit rate (94%) for psychopathic patients but a hit rate of only 61% for non-psychopathic patients. Half of the schizophrenic patients were mis-allocated to the psychopathic group. The results support the idea of an affective deficit common to psychopaths and schizophrenics, but suggest that psychopaths additionally show a deficit which may be characterized by a lack of goal-directed behaviour.     

Manipulation of self-destruction in three retarded children

The study attempted to isolate some of the environmental conditions that controlled the self-destructive behavior of three severely retarded and psychotic children. In the extinction study subjects were placed in a room where they were allowed to hurt themselves, isolated from interpersonal contact. They eventually ceased to hurt themselves in that situation, the rate of self-destruction falling gradually over successive days. In the punishment study, subjects were administered painful electric shock contingent on the self-destructive behavior. (1) The self-destructive behavior was immediately suppressed. (2) The behavior recurred when shock was removed. (3) The suppression was selective, both across physical locales and interpersonal situations, as a function of the presence of shock. (4) Generalized effects on other, non-shock behaviors, appeared in a clinically desirable direction. Finally, a study was reported where self-destructive behavior increased when certain social attentions were given contingent upon that behavior.     

Anxiety and the spelling and use in sentences of threat/neutral homophones

The disambiguation of threat/neutral homophones was investigated in high- and low-trait anxiety subjects who had been exposed to either a positive or a negative mood manipulation procedure. Subjects were required first to spell each auditorily presented word and second, to generate and speak a sentence using the word. Difference indices were calculated for the spelling and the sentence usage data, i.e. the number of threat minus neutral interpretations. Examination of these indices revealed that subjects exposed to the negative mood manipulation procedure produced relatively more threat than neutral interpretations (for both spelling and sentence usage) than did subjects exposed to the positive mood manipulation procedure. Multiple regression analyses revealed that both the trait anxiety and mood manipulation variables contributed significantly to the prediction of the difference index on the spelling task. In the analysis of the use of homophones in sentences, only the mood manipulation variable contributed significantly to the prediction of the difference index on the sentence usage task.