Psychology

Male rats carrying the testicular feminization mutation (Tfm-affected males) are insensitive to androgens, resulting in a female-typical peripheral phenotype despite possession of inguinal testes that are androgen secretory. Androgen-dependent neural and behavioral processes may likewise show atypical sexual differentiation. Interestingly, these mutant rats display elevated serum corticosterone, suggesting a chronic anxiety phenotype and dysregulated hypothalamic–pituitary–adrenal axis. In order to understand if elevated anxiety-like behavior is a possible mediating variable affecting the display of certain androgen-dependent behaviors, we compared the performance of Tfm-affected males to wild type males and females in the elevated plus maze (EPM). Two well-established indicators of anxiety-like behavior in the EPM were analyzed: total percentage of time spent on the open arms, and the percentage of open arm entries. We also analyzed the total number of open arm entries. Interestingly, Tfm-affected males spent less percentage of time on the open arms than both males and females, suggesting increased anxiety-like behavior. Percentage of open arm entries and the total number of arm entries was comparable between the groups, indicating that the observed decrease in the percentage of time spent on the open arms was not due to a global reduction in exploratory behavior. These data, in contrast to earlier reports, thus implicate androgen receptor-mediated functions in the expression of anxiety behaviors in male rats. Given that anxiety is widely reported as a precipitating factor in depression, studying the role of the androgen receptor in anxiety may give insights into the pathogenesis of major depressive disorder.

(BACKGROUND). Evidence that avoiding axillary lymph node dissection (AxD) strikes an appropriate balance between morbidity and recurrence risk in patients with invasive breast carcinoma generally is anecdotal and without a formally quantified basis. The current study presents a decision analysis of the difference in 5‐year disease free survival (DFS) rate between treatment scenarios with and without routine AxD. (METHODS). To derive quantitative estimates of the effect of avoiding AxD on 5‐year DFS, the authors examined outcomes for women undergoing 2 treatment scenarios: AxD or no AxD with adjuvant therapy decisions based on risk factors in the primary tumor. Eligible patients belonged to 2 lymph node metastases risk groups: low (patients without palpable lymph nodes and lymphatic or vascular invasion [LVI] negative tumors ≤ 0.5 cm in greatest dimension) and moderate (patients with mammographically detected, LVI negative tumors, between 0.6‐2.0 cm in greatest dimension or patients with palpable LVI negative tumors between 0.6‐1.0 cm in greatest dimension with nonpalpable lymph nodes). Along with observed data regarding treatment and recurrence, the authors employed estimates of the efficacy of chemotherapy, tamoxifen, and regional radiation therapy derived from published randomized trials to estimate the 5‐year DFS rate for treatment scenarios with and without AxD. (RESULTS). Patients in the low risk group had a 5% risk of lymph node metastases. In these women, eliminating AxD and treating no patients with chemotherapy and/or tamoxifen resulted in a < 1% decrease in the 5‐year DFS rate. Patients in the moderate risk group had a 10% risk of lymph node metastases. Eliminating AxD and treating only those women with Grade 3 tumors > 1 cm in greatest dimension with chemotherapy and/or tamoxifen resulted in a 1.8% decrease in the 5‐year DFS rate. However, if all patients in this group were treated with chemotherapy and/or tamoxifen and no AxD, the 5‐year DFS rate increased by 2.7%. (CONCLUSIONS). In patients with a low risk of lymph node metastases, it was estimated that eliminating AxD may result in only minimal changes in the estimated 5‐year DFS rate.

It is commonly assumed that the desire for a thin female physique and its pathological expression in eating disorders result from a social pressure for thinness. However, such widespread behavior may be better understood not merely as the result of arbitrary social pressure, but as an exaggerated expression of behavior that may have once been adaptive. The reproductive suppression hypothesis suggests that natural selection shaped a mechanism for adjusting female reproduction to socioecological conditions by altering the amount of body fat. In modern Western culture, social and ecological cues, which would have signaled the need for temporary postponement of reproduction in ancestral environments, may now be experienced to an unprecedented intensity and duration.

Post-adoption service use and unmet service needs were examined longitudinally in three matched groups of children: children adopted from Romanian orphanages following a minimum of eight months' institutional experience (RO: n = 36); children from Romania who were destined for orphanages but were adopted early in infancy (EA: n = 25); and Canadian born non-adopted children (CB: n = 42). Data were collected when the adoptees had been in their adoptive homes for 11 months, at age 4.5 years and 10.5 years. Results indicated higher rates of service use and unmet service needs across time in the RO group. Unmet service needs in the RO group may be due in part to the unique challenges faced by post-institutionalized adoptees. Service use in the EA group jumped significantly at Phase 3, suggesting that the impact of their lesser degree of early deprivation was seen later in development under the additional challenge and stress of the demands of school. Findings, particularly from the EA group, supported the suggestion that adoptive parents have a lower threshold for referring their children for clinical services than do non-adoptive parents. Service needs of adoptees changed over time and those with unmet needs experienced greater challenges than those whose service needs were met.

The Dark Triad Traits (DTT: consisting of Psychopathy, Machiavellianism, and Narcissism) are clearly linked to deceptive and manipulative behaviour, yet little is known about whether people with high levels of DTTs deceive themselves in order to convince others. This online study investigated whether the DTTs predicted false memory levels, assessed by the DRM paradigm (Deese, 1959: Deese & McDermott, 1995), which was modified to include three neutral word lists and three word lists constructed around DTT-related lures (Power, Control, and Status). The sample (n=161) consisted of 136 females and 25 males from the undergraduate research pool and through social networks. Among the three DTTs, psychopathy was most closely predictive of self-reported dishonesty. However, results showed that psychopathy and narcissism significantly predicted lower rates of adopting false memories for neutral lures, whereas Machiavellianism was somewhat predictive of adopting higher false memory levels, particularly for the DTT lure (control). These findings indicate that among the DTTs, psychopathy and narcissism are associated with a lower likelihood of self-deception, while Machiavellianism may increase the probability of self-deception.

There is considerable evidence that people process information in a manner that favours prior beliefs, and that they are resistant to evidence against those beliefs. People who believed in an afterlife were recruited, and they all indicated their level of confidence. This study analyzed the effect of self-construal, mood, and nationality on openness to belief-contradicting evidence. Our study used a 2 (self-construal: rational vs fallible) X 2 (mood: positive vs negative) X 2 (nationality: Western vs non-Western) factorial design. Self-construal was manipulated through the use of questionnaires, while mood was manipulated with videos. All participants were exposed to arguments that contradicted their beliefs, and they indicated how convincing the arguments were. Their ratings of the arguments were our measure of openness to belief-contradicting evidence. There was a strong negative correlation between initial belief confidence and ratings of the arguments. Participants who were more confident in their beliefs tended to find the arguments unconvincing, but participants with less confidence tended to find the arguments convincing. Self-construal did not produce significant differences in ratings of the arguments, and neither did the mood manipulation. There was also no significant difference in average ratings between Westerners and non-Westerners. However, there was an unexpected interaction between nationality and self-construal. A fallible self-construal led to significantly lower ratings of the arguments for Westerners, while it led to higher ratings of the arguments for non-Westerners. Possible explanations of this finding are discussed, including identity threat and differences is self-serving bias.

Although there has been extensive research on the independent predictor variables of high school drop out, less research has been dedicated to explaining the relationships among these variables. This exploratory study examined the relationship between socioeconomic status (SES) and academic self-efficacy, specifically to see if delay discounting could be acting as a moderator between the two variables. Participants were 20 high school students from a medium-sized city in Western Canada, all enrolled in a dropout prevention program. Data was collected via surveys on three separate occasions throughout the program. The results indicated a non-significant positive correlation between SES measures and academic self-efficacy. Delay discounting, defined as lack of willingness to wait for larger, but delayed rewards, had a non-significant negative correlation with both academic self-efficacy and two of three SES measures. Delay discounting was a significant moderator of the relationship between SES and academic self-efficacy. Lastly, the early school-leaving sample was found to have significantly higher levels of delay discounting than a college-based comparison sample. These findings suggest that the individual difference variable of delay discounting may help explain inconsistent relationships between socioeconomic background and likelihood of academic success.

Caffeine is one of the most ubiquitous drugs in the world, and is often consumed for its cognitive enhancing properties. The current research investigated the influence of caffeine on two commonly used measures of risky decision making (the Iowa Gambling Task and the Balloon Analogue Risk Task). Findings indicated that caffeine improved performance on the IGT but not on the BART. However, inclusion of individual differences on decision making style and impulsivity generated regression models that explained a significant proportion of variance in performance on the IGT and BART. Multiple significant correlations existed among a variety of individual difference trait measures of decision-making style, impulsive tendencies and risk-taking behaviour. Results and implications are discussed in terms of two prominent decision-making theories as well as prior research, and further research directions are suggested that may help elucidate the apparently contradictory effects of caffeine on two distinct measures of risky decision making. Author keywords:

This study observed Systems 1 (heuristic) and Systems 2 (cognitively effortful) decision making styles in individuals undergoing high and low intensity exercise versus a no exercise control group. The attraction effect and delay discounting were measured to test the hypothesis that post exercise hyperglycaemia can reduce heuristic-based decision making and increase cognitively effortful decisions. Individual differences in decision making traits were also assessed using the General Decision Making Styles questionnaire. Results showed that high-intensity exercise can induce elevation in blood glucose; however this effect was observed only in half the sample. Participants in the high intensity exercise condition were significantly more likely than those in the low intensity exercise condition to elicit post exercise hyperglycaemia. Additionally, results from this study show that higher blood glucose is associated with a greater probability of choosing the non-heuristic option in the apartment task; thus signifying less reliance on heuristic based System 1 decision making. Furthermore, in the delay discounting task, exploratory analyses suggest that high-intensity exercise-induced hyperglycaemia may rescue optimal decision-making for individuals who tend to make more intuitive decisions (i.e., are more reliant on System 1). Further studies with larger sample sizes are needed to further elucidate the effects of exercise on decision making, taking into account blood glucose changes and individual difference profiles.