Psychometric properties of the life events checklist

The Life Events Checklist (LEC), a measure of exposure to potentially traumatic events, was developed at the National Center for Posttraumatic Stress Disorder (PTSD) concurrently with the Clinician Administered PTSD Scale (CAPS) to facilitate the diagnosis of PTSD. Although the CAPS is recognized as the gold standard in PTSD symptom assessment, the psychometric soundness of the LEC has never been formally evaluated. The studies reported here describe the performance of the LEC in two samples: college undergraduates and combat veterans. The LEC exhibited adequate temporal stability, good convergence with an established measure of trauma history -- the Traumatic Life Events Questionnaire (TLEQ) -- and was comparable to the TLEQ in associations with variables known to be correlated with traumatic exposure in a sample of undergraduates. In a clinical sample of combat veterans, the LEC was significantly correlated, in the predicted directions, with measures of psychological distress and was strongly associated with PTSD symptoms.     

Most of the girls are alright, but some aren't: Personality trajectory groups from ages 14 to 24 and some associations with outcomes

Personality traits show normative patterns of development toward maturity during adolescence. Yet individuals follow these normative patterns to differing degrees. This study used growth mixture modeling to characterize personality development patterns and their associations with outcomes in a population-based sample of 1,537 girls aged 14 to 24. The authors used latent class analysis to identify 3 trajectory groups labeled alright (47%), growing up (42%), and trouble (11%). Alright group members were more likely at age 24 to have completed college, remained involved with their families, and obtained good jobs. Trouble group members were more likely to be involved with drugs and alcohol, to display interpersonal problems, and to behave antisocially. Growing up group members fell in between.     

The effect of restraint beliefs on alcohol-seeking behavior

Individuals who believe that they have high levels of restraint over motivated behaviors such as cigarette smoking are, paradoxically, more likely to engage in those behaviors when tempted (Nordgren, Van Harreveld, & Van Der Pligt, 2009). Our aim was to experimentally manipulate heavy drinkers' beliefs about their drinking restraint to examine the effect on drinking behavior. Sixty heavy drinkers completed an implicit association test and a stop-signal task before receiving bogus feedback on their task performance that indicated that they had either high or low levels of drinking restraint. Participants then completed a bogus taste test in which they were able to consume beer and a soft drink. Results indicated that the group falsely led to believe that they had a high level of drinking restraint subsequently consumed more beer than the group led to believe that they had a low level of drinking restraint. This study demonstrates that beliefs about drinking restraint can influence drinking behavior, in that individuals who overestimate their control over drinking are at greater risk of drinking to excess when exposed to tempting situations.     

Personality stability in late adulthood: a behavioral genetic analysis

A sample of 833 twins from the Minnesota Twin Study of Adult Development and Aging completed the Multidimensional Personality Questionnaire (MPQ; Tellegen, 1982) twice, averaging 59.4 (sd=9.7) years of age at first and 64.4 (sd=10.2) years of age at second testing (average retest interval 5.0 years, sd=2.36, range 1.0-10.4 years). Both means and standard deviations of scale scores were extremely stable from first to second testing. In addition, sample participants tended to retain their rank order on the scales (average r=.76 across scales). Bivariate biometric analyses showed that the genetic influences on most of the scale scores were almost perfectly correlated across the two waves (range .95 to 1.00). The nonshared environmental influences were also highly correlated across the two waves (range .53 to .73). Models specifying identical variance components at the two time points and fixing the genetic correlation to 1.00 provided improved fit. The results suggest that the high stability of personality in later adulthood has a strong genetic foundation, supplemented by stability of environmental effects.     

Sex differences in parietal lobe morphology: relationship to mental rotation performance

Structural magnetic resonance imaging (MRI) studies of the human brain have reported evidence for sexual dimorphism. In addition to sex differences in overall cerebral volume, differences in the proportion of gray matter (GM) to white matter (WM) volume have been observed, particularly in the parietal lobe. To our knowledge there have been no studies examining the relationship between the sex differences in parietal lobe structure and function. The parietal lobe is thought to be involved in spatial ability, and particularly involved in mental rotation. The purpose of this study is to examine whether sex differences in parietal lobe structure are present, and if present to relate these differences to performance on the mental rotations test (MRT). We found that women had proportionately greater gray matter volume in the parietal lobe compared to men, and this morphologic difference was disadvantageous for women in terms of performance on the MRT. In contrast, we found that men compared to women had proportionately greater parietal lobe surface area, and this morphologic difference was associated with a performance advantage for men on mental rotation. These findings support the possibility that the sexual dimorphism in the structure of the parietal lobe is a neurobiological substrate for the sex difference in performance on the mental rotations test.