Drug effects on repeated acquisition: comparison of cumulative and non-cumulative dosing

Pigeons acquired a different four-response chain each session by responding sequentially on three keys in the presence of a sequence of four colors. The response chain was maintained by food presentation under a fixed-ratio schedule. Errors produced a brief timeout but did not reset the chain. Each day there were four 15-minute sessions, with a 10-minute inter-session interval. Cumulative dose-effect curves for phencyclidine, pentobarbital, and d-amphetamine were obtained by giving an injection before each of the four sessions; successive injections increased the cumulative dose in equally spaced logarithmic steps. For comparison, non-cumulative doses of each drug (i.e., doses not preceded by other doses on the same day) were also tested. As the cumulative dose of each drug increased, the overall response rate decreased, the percent errors increased, and there was less within-session error reduction (acquisition). With phencyclidine and pentobarbital, the rate-decreasing and error-increasing effects tended to be greater with a non-cumulative dose than with the corresponding cumulative dose. In contrast, with d-amphetamine, the effects were considerably greater with the cumulative doses. The results indicate that although the cumulative-dosing procedure saved a substantial amount of time in determining dose-effect curves, there were quantitative differences in effects between cumulative and non-cumulative doses.     

Visuospatial ability, accuracy of size estimation, and bulimic disturbance in a noneating-disordered college sample: a neuropsychological analysis

The relationship between visuospatial ability and size accuracy in perception was assessed in 69 normal college females. In general, correlations indicated small associations between visuospatial defects and size overestimation and little relationship between visuospatial ability and level of bulimic disturbance. Implications for research on the size overestimation of body image are addressed.     

Peer support telephone dyads for elderly women: Was this the wrong intervention?

Tested a preventive intervention in which peer telephone dyads were developed for low-income, community-living, elderly women with low perceived social support. After an initial assessment, respondents were randomly assigned to either an assessment-only control or received 10 weeks of friendly staff telephone contact. After a second assessment, participants receiving the staff contact were randomly assigned to continue that contact or were paired in dyads to continue phone contact with one another. Dependent variables were measures of perceived social support, morale, depression, and loneliness. All groups, particularly the staff contact group, showed some improvement in mental health scores over time, but there were no significant differences between intervention groups, or between intervention and assessment-only control groups. The results suggest that participation in the study and in personal assessment interviews at home were probably morale enhancing, and that additional telephone contact did not significantly add to that effect. Evidence also indicates that, in this sample, low perceived family support was significantly related to poor mental health, so it is possible that a program designed to increase friend support may have been the wrong intervention.     

The effects of late-life spousal bereavement over a 30-month interval

Self-report measures of grief, depression, and general psychopathology were studied in widows and widowers over a 2.5-year period following death of their partner. A comparison sample of men and women was also followed for the same period. Differences in severity of depression and psychopathology previously reported at 2 months postloss (Gallagher, Breckenridge, Thompson, & Peterson, 1983) diminished to nonsignificant levels at 12 and 30 months. However, significant differences between bereaved and comparison subjects on measures of grief were still apparent 30 months after spousal loss. A main effect of gender for depression and psychopathology (but not for grief) was found at 2 and 12 months: Women reported more distress than men regardless of bereavement status. Results indicate that the experience of grief persists for at least 30 months in both older men and women who have lost their spouse.     

Gender differences in autonomous and social achievement orientations

This research examined gender differences in orientations toward autonomous and social achievement. Three independent samples of subjects (total N= 359 males and 574 females) completed measures of achievement orientation (including Strumpfer's [1975] Autonomous Achievement Values and Social Achievement Values scales) and relevant cognitive, affective, and behavioral variables. Correlational and factor analyses clearly identified distinct autonomous and social achievement factors for both men and women in each of the samples. Examination of the correlates of achievement orientation indicated that whereas an autonomous achievement orientation is similarly expressed in males and females, there are considerable sex differences in the expression of an orientation toward social achievement. In particular, a social achievement orientation was associated with concerns over social approval and responsiveness to social influence among males, but was generally unrelated to these factors among females. Findings are discussed in terms of several recent hypotheses concerning the effects of sex role norms on the development and expression of achievement needs in men and women.     

An experimental analysis of the effects of d-amphetamine and cocaine on the acquisition and performance of response chains in monkeys.

In one component of a multiple schedule of food presentation, monkeys acquired a different four-response chain each session by responding sequentially on three keys in the presence of four geometric forms (learning). In the other component, the four-response chain was the same each session (performance). Both d-amphetamine and cocaine, at the higher doses, disrupted the behavior in the learning component; the overall response rate decreased, the overall accuracy was impaired (i.e., percent errors increased), and there was less within-session error reduction. The performance component was generally less sensitive than the learning component to the disruptive effects of both drugs on rate and accuracy. After pre-feeding or during an extended session, the response rate decreased in both components, but accuracy was generally unaffected. When the four discriminative stimuli in both components were removed, the behavior was disrupted to a greater extent in the performance component. The disruptive effects of both drugs on behavior in the learning component were attenuated when the drugs were administered during the session after the response chain had been acquired. It was concluded that the greater sensitivity of the learning component to disruptive drug effects is related to the relatively weak stimulus control and/or the lower rate of reinforcement associated with that component.