One-trial overshadowing

Two experiments on conditioned suppression in rats examined the extent to which conditioning to a tone was overshadowed by the presence of a light. When animals received four conditioning trials, a light of moderate intensity significantly overshadowed the tone. On the first trial of conditioning, however, the light had no effect on conditioning to the tone, unless (Experiment I) its intensity was increased, or (Experiment II) it occurred in closer temporal contiguity to reinforcement than the tone. The results establish that overshadowing can occur on the first trial of conditioning, contrary to the predictions of several theories, but suggest that this may be for different reasons from those operating to produce overshadowing over a series of conditioning trials.     

Upsetting Behavior: Reactions to Personal and Bystander Sexual Harassment Experiences

The current research was designed to examine objective and contextual factors related to the appraisal of potentially sexually harassing situations. Working female participants (n = 208) from a mid-sized southwestern university completed a workplace experiences survey in small groups. The majority of participants were Hispanic/Latina (77.9%). We predicted that characteristics of personal harassment experiences (e.g., number of distinct types of behaviors experienced, frequency, duration) and bystander harassment experiences would contribute independently to how upset women were by their own sexual harassment experiences. Results indicated that characteristics of personal harassment experiences and bystander experiences did predict how upset women were by their own gender harassment and by unwanted sexual attention experiences. Results are discussed in terms of the importance of considering multiple types of workplace stressors (e.g., personal and bystander sexual harassment experiences) and their relation to the appraisal process.     

Taxometric Investigation of PTSD: data from two nationally representative samples

Current psychiatric nosology depicts posttraumatic stress disorder (PTSD) as a discrete diagnostic category. However, only one study has examined the latent structure of PTSD, and this study suggested that PTSD may be more accurately conceptualized as an extreme reaction to traumatic life events rather than a discrete clinical syndrome. To build on the existing literature base, the present research examined the latent structure of posttraumatic stress reactions by applying three taxometric procedures (MAXEIG, MAMBAC, and L-Mode) to data collected from large nationally representative samples of women (ns = 2684 and 3033) and adolescents (n = 3775). Results consistently provided evidence for a dimensional PTSD solution across samples and statistical procedures. These findings have important implications for the theory, assessment, and investigation of posttraumatic stress reactions.     

A neural correlate of consciousness related to repression

In previous research Libet (1966) discovered that a critical time period for neural activation is necessary in order for a stimulus to become conscious. This necessary time period varies from subject to subject. In this current study, six subjects for whom the time for neural activation of consciousness had been previously determined were administered a battery of psychological tests on the basis of which ratings were made of degree of repressiveness. As hypothesized, repressive subjects had a longer critical time period for neural activation of consciousness, suggesting the possibility that this neurophysiological time factor is a necessary condition for the development of repression.