Digital measurement of operant disk press force maintained in CD-1, BALB/c, and C57BL/6 mice

Force of disk press responses by inbred (C57BL/6 and BALB/c) and outbred (CD-1) mice were measured with a PC/DOS-based system, which allowed for continuous measurement of pressing, as well as for control of reinforcer presentation on the basis of response-force dimensions. Photobeam-based measurement of mouse entry into a hopper where reinforcers were presented provided additional information about anticipatory and consumatory behavior in relation to environmental stimuli leading up to reinforcer delivery Disk pressing was generated and measured with the use of an analog-to-digital interface with all three mouse strains. The strains differed in the physical and temporal characteristics of the disk press, as well as in the behavioral chain leading to reinforcer presentation. These measurement methods appear well suited for quantitating functional behavioral differences occasioned by genetic variations in mice.     

Effects of contingency violations on the extinction of a conditioned fear inhibitor and a conditioned fear excitor

Rats were used in a conditioned-suppression paradigm to assess the effects of contingency variations on responding to a conditioned inhibitor (CS-) and a conditioned excitor (CS+). In Experiment 1, various unconditioned stimulus (US) frequencies were equated across the presence and absence of a CS- in the context of either background cues (continuous-trial procedure) or an explicit neutral event (discrete-trial procedure). With both procedures, a CS-alone treatment enhanced inhibition, whereas treatments involving 50% or 100% reinforcement for the CS- eliminated inhibition without conditioning excitation to that CS. The latter outcome also occurred in Experiment 2, with discrete-trial training equating considerably reduced US frequencies for the presence and absence of the CS-. In further evidence that inhibition was eliminated without conditioning excitation to the CS-, Experiment 3 showed that a novel CS did not acquire excitation when 25%, 50%, or 100% reinforcement was equated across the presence and absence of that CS in the context of a discrete-trial event. Using the procedures of Experiment 1, Experiment 4 showed that a CS+ was extinguished by a CS-alone treatment but was substantially maintained by treatments involving 50% or 100% uncorrelated reinforcement. These effects for a CS+ and a CS- implicate CS-US contiguity, rather than contingency, as the factor determining the extinction of a CS.     

Germ-line gene therapy and the clinical ethos of medical genetics

Although the ability to perform gene therapy in human germ-line cells is still hypothetical, the rate of progress in molecular and cell biology suggests that it will only be a matter of time before reliable clinical techniques will be within reach. Three sets of arguments are commonly advanced against developing those techniques, respectively pointing to the clinical risks, social dangers and better alternatives. In this paper we analyze those arguments from the perspective of the client-centered ethos that traditionally governs practice in medical genetics. This perspective clarifies the merits of these arguments for geneticists, and suggests useful new directions for the professional discussion of germ-line gene therapy. It suggests, for example, that the much discussed prospect of germ-line therapy in human pre-embryos may always be more problematic for medical genetics than adult germ-line interventions, even though the latter faces greater technical difficulties.     

The Perception of Teasing Scale (POTS): a revision and extension of the Physical Appearance Related Teasing Scale (PARTS)

This article describes the development and validation of a revised measure for the assessment of history of being teased about physical appearance. Study 1 involved the preliminary psychometric evaluation of the questionnaire on a sample of 227 college women, Two factors emerged: Weight-Related Teasing (WT) and Teasing About Abilities/Competencies (Competency Teasing; CT). The integrity of the factor structure of these two scales was established in Study 2 with a sample of 87 college women. Internal consistency ratios in this sample were also found to be acceptable. In Study 3, 92 college women were administered measures of body image, eating disturbance, and self-esteem to test for convergence with the Perception of Teasing Scale. Subjects also rated teasing items for frequency and effect (e.g., how upset they were by the teasing). Two-week test-retest reliabilities for these measures were acceptable. Weight-Related Teasing correlated to a greater degree with other measures than Competency Teasing. Regression analyses revealed the importance of a frequency versus effect dimension. Findings are discussed in light of recent research on developmental factors in body image and eating disturbance.     

Encouraging College Males to Perform Testicular Self-Examination: Evaluation of a Persuasive Message Based on the Revised Theory of Reasoned Action1

This study evaluated the effect of a persuasive message derived from a revised version of the theory of reasoned action on the performance of testicular self-examination (TSE). Subjects (114 male college students) were randomly assigned to listen to a taped persuasive message challenging unfavorable outcome beliefs (as suggested by the theory of reasoned action), a message on testicular cancer information, or no message. All subjects then completed a questionnaire operationalizing the components of the theory of reasoned action (revised to incorporate self-efficacy). As predicted, there was a significant relationship between exposure to the persuasive message and self-reported TSE performance (χ²(2) = 15.66, p < .0001). Sixty-three (71.23%) of the subjects contacted at a 4-week follow-up reported performing the exam. Of those, 44.23% had heard the theory-based message, 36.54% had heard the informational message, and 19.23% had not been exposed to a message. A path analysis of the relationships among components of the theoretical model provided partial support for the hypothesized causal pathways between message exposure and TSE intention and behavior.     

The Nature and Correlates of Psychological Adjustment in Gay Men with AIDS-Related Conditions1

This study assessed differences in the psychological adjustment of gay men who tested positive for the antibody to the human immunodeficiency virus (HIV). Twenty-one were symptomatic for AIDS, and 27 were asymptomatic. A group of 15 gay men who tested negative for the HIV was included as a comparison group. Men in the three groups were equivalent on demographic variables. Symptomatic men reported more health problems than either asymptomatic or seronegative men. Relative to men who were symptomatic, those who were asymptomatic reported more death anxiety, less optimism, and greater severity of psychological distress, and reported more frequent use of avoidance and distancing as coping strategies. The poor psychological functioning of asymptomatic subjects was attributed to the uncertainty regarding their future health status. Generally, positive psychological well-being of symptomatic and asymptomatic men was related to the infrequent use of avoidance coping strategies and high satisfaction with perceived social support.