Decline of maternal behavior in the virgin and lactating rat.

Sensitized virgins and postpartum lactating mothers, both exhibiting maternal behavior, were given donor litters that increased in age by 1 day, for 28 days, starting at the onset of maternal behavior. Each day females were tested for maternal behavior with pups 4-8 days old: Maternal care (i.e., nursing/crouching, retrieving, nest building and licking) and maternal withdrawal, rejection, and prevention of nursing were recorded. After the ninth day, females were also tested with the progressively older pups from 10 to 28 days of age with which they were living. Virgins and lactating mothers showed generally similar patterns of maternal care although some differences were found, and they declined in maternal behavior toward the older pups in a similar manner. Maternal behavior did not decline in tests with younger pups. The results are interpreted as supporting the hypothesis that the decline as well as the maintenance of maternal behavior postpartum is nonhormonally mediated.     

Electrical aversion therapy with alcoholics: An analogue study

Chronic alcoholic patients matched on age, education and length of problem drinking were assigned to one of three treatment conditions, with 10 subjects in each group: (1) Electrical Aversion Conditioning (high shock paired with alcohol sips); (2) Control Conditioning (very low shock paired with alcohol sips); and (3) Group Therapy (confrontation psychotherapy). Groups 2 and 3 were included to control for possible ‘attention-placebo’ and expectancy factors involved in the conditioning procedures. Subjects in each group were given instructions designed to produce high expectancy for therapeutic success. Pre-post measures of alcohol consumption and attitudes toward alcohol were obtained using an analogue ‘taste test’ assessment procedure. No statistically significant differences in reduced alcohol consumption or attitudes toward alcohol were found among the groups. Trends in the data support the contention that effects of electrical aversion may be more related to such factors as therapeutic instructions, expectancy, specificity of the procedure or experimental demand characteristics than to conditioning factors.     

Natural and contrived experience in a reasoning problem

This study is concerned with the effects of prior experience on a deceptive reasoning problem. In the first experiment the subjects (students) were presented with the problem after they had experienced its logical structure. This experience was, on the whole, ineffective in allowing subsequent insight to be gained into the problem. In the second experiment the problem was presented in “thematic” form to one group, and in abstract form to the other group. Ten out of 16 subjects solved it in the thematic group, as opposed to 2 out of 16 in the abstract group. Three hypotheses are proposed to account for this result.     

Some anomalies in the study of experimental pain

The experiment was designed in an attempt to throw some light on certain anomalies connected with the assessment of pain threshold by the Limiting Method. It is argued that an anchoring effect, similar to that described by Helson (1947), accounts for the low pain threshold values found when a small stimulus-interval is used.     

Human Psychophysical Functions,an Update: Methods for Identifying their form; Estimating their Parameters; and Evaluating the Effects of Important Predictors

Stevens’ power law for the judgments of sensation has a long history in psychology and is used in many psychophysical investigations of the effects of predictors such as group or condition. Stevens’ formulation \(\varPsi = {aP}^{n}\), where \(\varPsi \) is the psychological judgment, P is the physical intensity, and \(n\) is the power law exponent, is usually tested by plotting log \((\varPsi )\) against log (P). In some, but by no means all, studies, effects on the scale parameter, \(a\), are also investigated. This two-parameter model is simple but known to be flawed, for at least some modalities. Specifically, three-parameter functions that include a threshold parameter produce a better fit for many data sets. In addition, direct non-linear computation of power laws often fit better than regressions of log-transformed variables. However, such potentially flawed methods continue to be used because of assumptions that the approximations are “close enough” as to not to make any difference to the conclusions drawn (or possibly through ignorance the errors in these assumptions). We investigate two modalities in detail: duration and roughness. We show that a three-parameter power law is the best fitting of several plausible models. Comparison between this model and the prevalent two parameter version of Stevens’ power law shows significant differences for the parameter estimates with at least medium effect sizes for duration.     

Behavioral and Psychophysiological Effects of a Yoga Intervention on High-Risk Adolescents: A Randomized Control Trial

The purpose of this study was to conduct a pilot randomized control trial to test whether a mindful yoga intervention had a beneficial impact on substance use and its psychological and psychophysiological correlates in high-risk adolescents. Research on yoga has generated growing evidence for its positive effects on physical and emotional health. However, most studies are conducted with adults, with few controlled studies conducted with youth. We designed a 20-session mindful yoga intervention for adolescents attending a school for students at high-risk for dropping out. The 50-min classes were offered three times a week. The participants (mean age = 16.7 years) were randomly assigned to control and intervention groups. Multi-rater (student, teacher), multi-method (survey, cognitive, psychophysiological) data were collected before and after the yoga curriculum. At post-test, students in the yoga condition, as compared to control students, exhibited trends toward decreased alcohol use and improved teacher-rated social skills (p < .10); and showed a non-significant increase in arousal in response to relevant stimuli as measured in skin conductance. Significant effects were not found on hypothesized proximal measures of self-regulation, mood, mindfulness, or involuntary engagement coping. Future research is needed to replicate and expand upon our findings. Studies are also needed with larger samples to further investigate potential mediators and moderators of yoga’s effects.     

Revisiting the mediating role of leader–member exchange in transformational leadership: the differential impact model

Transformational leadership (TFL) has been proposed as an essential antecedent of leader–member exchange (LMX), which in turn affects outcomes in organizations. We extend this mediation hypothesis in two ways by proposing a differential impact model, which we test on three organizational outcomes: employee job satisfaction, employee organizational commitment, and leader effectiveness. First, we extend LMX’s mediational impact—which has previously only been tested for employee outcomes—to leader effectiveness. Second, we argue that this mediation will be stronger for outcomes that are more proximal rather than distal to dyadic relations between leader and followers (high proximity: job satisfaction; medium proximity: organizational commitment; low proximity: leader effectiveness). Meta-analytic structural equation modelling based on 132 studies revealed that LMX mediates TFL’s relationships with employee outcomes (more strongly for job satisfaction than for commitment), but not with leader effectiveness, whereas TFL showed a stronger direct link to leader effectiveness. The findings suggest that TLF and LMX contribute differentially to organizational outcomes depending on their proximity to dyadic relations between leaders and followers. The differential impact model uncovers leadership effectiveness processes, integrates influential leadership theories, and highlights the importance of distinguishing between different outcome measures and the processes facilitating them.