Additive factors analysis of reaction time with alphanumericals and line orientations as stimuli

Most additive factors method (AFM) analyses of choice reaction time (CRT) have used alphanumerics whereas tests of single process models have often used line length or line orientation. The suggestion is raised that commonly observed additive effects of variables on CRT might not apply to stimuli of the latter category. This would mean a severe limitation of the AFM in that the stage structure of choice reactions would be stimulus specific. The issue is addressed in two experiments. The first showed additive effects of stimulus quality and stimulus-response compatiblility for both alphanumerics and line orientations as stimuli. The second showed that for both stimulus categories the effect of stimulus quality was fully reflected in visual fixation time. Together the results argue against a single central process and favour a stage model of CRT.     

Toward the content validity of premenstrual dysphoric disorder: do anger and irritability more than depressed mood represent treatment-seekers' experiences?

The content validity of Premenstrual Dysphoric Disorder in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM-IV-TR) has been questioned in the literature. We tested whether mood-related symptoms reported by 26 women seeking treatment for premenstrual disorders were among the proposed criteria. These women were asked to list their premenstrual symptoms and rate the severities of listed symptoms daily for two menstrual cycles before treatment. They completed semistructured interviews to differentiate symptoms of Premenstrual Dysphoric Disorder from those of other psychiatric disorders in women who had other disorders. All participants reported functional interference due to the symptoms. 19 symptoms of or similar to those of Premenstrual Dysphoric Disorder were among the 22 most frequent premenstrual symptoms experienced. Premenstrual depressed mood was less frequent than premenstrual irritability or anger when other psychiatric disorders such as major depression were taken into account. Results suggest that the DSM-IV-TR criteria have generally good content validity but may need revision to represent treatment-seekers experiences more accurately.     

Yoga-based guided relaxation reduces sympathetic activity judged from baseline levels

35 male volunteers whose ages ranged from 20 to 46 years were studied in two sessions of yoga-based guided relaxation and supine rest. Assessments of autonomic variables were made for 15 subjects, before, during, and after the practices, whereas oxygen consumption and breath volume were recorded for 25 subjects before and after both types of relaxation. A significant decrease in oxygen consumption and increase in breath volume were recorded after guided relaxation (paired t test). There were comparable reductions in heart rate and skin conductance during both types of relaxation. During guided relaxation the power of the low frequency component of the heart-rate variability spectrum reduced, whereas the power of the high frequency component increased, suggesting reduced sympathetic activity. Also, subjects with a baseline ratio of LF/HF > 0.5 showed a significant decrease in the ratio after guided relaxation, while subjects with a ratio < or = 0.5 at baseline showed no such change. The results suggest that sympathetic activity decreased after guided relaxation based on yoga, depending on the baseline levels.     

Age differences in overlapping-task performance: evidence for efficient parallel processing in older adults

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T1) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T1 at least as efficiently as younger adults.     

Angry adolescents who worry about becoming violent

In the present study, 31 of 89 adolescents responded affirmatively to the following statement: "Sometimes I get so angry that I worry I will become violent." These adolescents (the anger group) were compared with the nonanger group, and several differences were found. The anger group (1) reported less intimacy with parents, received less support from them, and was less close to siblings; (2) had more opposite-sex friends, dated more frequently, and more frequently had a boyfriend or girlfriend; (3) had a lower grade point average; (4) were more depressed; and (5) used marijuana more frequently. Results of a regression analysis revealed that depression and dating were the only significant predictors of anger, explaining 17% of the variance.     

Deletion of the mu opioid receptor results in impaired acquisition of Pavlovian context fear

The mu opioid receptor may constitute a critical component of a negative feedback system that regulates Pavlovian fear conditioning. We investigated context fear conditioning acquisition and expression in mu opioid receptor knockout mice (on an inbred, C57 genetic background). We discovered that the mu receptor knockout results in an unexpected and significant deficit in context fear acquisition. Mice lacking the mu receptor showed normal fear acquisition when subjected to a 1-day fear conditioning protocol but evinced deficient fear learning when acquisition was conducted across 5 days. The knockout mice showed normal reactivity to footshock in both fear conditioning protocols. Finally, we confirmed the effectiveness of the receptor deletion in the C57 strain by subjecting the mice to a test of morphine analgesia in the hot-plate assay. As has been seen with mixed genetic background, the receptor deletion resulted in a complete lack of analgesic response to 10 mg/kg morphine. Surprisingly, mice with a single copy of the mu receptor gene (heterozygous knockouts) showed intact sensitivity to morphine but a significant deficit in Pavlovian fear conditioning. The results indicate that deletion of the mu receptor gene impairs fear conditioning and that the conditioning and analgesia effects of heterozygous deletion are dissociable. The conditioning deficit seen in this line of mice may be related to impairment in hippocampus function.     

A longitudinal study of gender-related cognition and behaviour

Gender schema theory proposes that children's acquisition of gender labels and gender stereotypes informs gender-congruent behaviour. Most previous studies have been cross-sectional and do not address the temporal relationship between knowledge and behaviour. We report the results of a longitudinal study of gender knowledge and sex-typed behaviour across three domains in children tested at 24 and 36 months (N = 56). Although both knowledge and sex-typed behaviour increased significantly between 2 and 3 years, there was no systematic pattern of cross-lagged correlations between the two, although some concurrent relationships were present at 24 months. Future longitudinal work might profitably focus on younger children using reliable preverbal measures of gender knowledge and employing a shorter lag between measurement times.     

Associations in the course of personality disorders and Axis I disorders over time

In this study, the authors examined time-varying associations between schizotypal (STPD), borderline (BPD), avoidant (AVPD), or obsessive-compulsive (OCPD) personality disorders and co-occurring Axis I disorders in 544 adult participants from the Collaborative Longitudinal Personality Disorders Study. The authors tested predictions of specific longitudinal associations derived from a model of crosscutting psychobiological dimensions (L. J. Siever & K. L. Davis, 1991) with participants with the relevant Axis I disorders. The authors assessed participants at baseline and at 6-, 12-, and 24-month follow-up evaluations. BPD showed significant longitudinal associations with major depressive disorder and posttraumatic stress disorder. AVPD was significantly associated with anxiety disorders (specifically social phobia and obsessive-compulsive disorder). Two of the four personality disorders under examination (STPD and OCPD) showed little or no association with Axis I disorders.     

Priming of non-speech vocalizations in male adults: the influence of the speaker's gender

Previous research reported a priming effect for voices. However, the type of information primed is still largely unknown. In this study, we examined the influence of speaker's gender and emotional category of the stimulus on priming of non-speech vocalizations in 10 male participants, who performed a gender identification task. We found a significant priming effect, which was greater for female than male vocalizations. In contrast, the emotional category of the stimuli did not appear to modulate the magnitude of priming. These data suggest that different aspects of the information conveyed in non-speech vocalizations may contribute differently to behavioral priming, possibly influenced by task relevance.