Observers can voluntarily shift their psychometric functions without losing sensitivity

Psychometric sensory discrimination functions are usually modeled by cumulative Gaussian functions with just two parameters, their central tendency (μ) and their slope (1/σ). These correspond to Fechner's "constant" and "variable" errors, respectively. Fechner pointed out that even the constant error could vary over space and time and could masquerade as variable error. We wondered whether observers could deliberately introduce a constant error into their performance without loss of precision. In three-dot vernier and bisection tasks with the method of single stimuli, observers were instructed to favour one of the two responses when unsure of their answer. The slope of the resulting psychometric function was not significantly changed, despite a significant change in central tendency. Similar results were obtained when altered feedback was used to induce bias. We inferred that observers can adopt artificial response criteria without any significant increase in criterion fluctuation. These findings have implications for some studies that have measured perceptual "illusions" by shifts in the psychometric functions of sophisticated observers.     

Elevated suicide rates at high altitude: sociodemographic and health issues may be to blame

Suicide rates are higher at high altitudes; some hypothesize that hypoxia is the cause. We examined 8,871 suicides recorded in 2006 in 15 states by the National Violent Death Reporting System, with the victim's home county altitude determined from the National Elevation Dataset through FIPS code matching. We grouped cases by altitude (low<1000m; middle=1000-1999m; high≥2000m). Of reported suicides, 5% were at high and 83% at low altitude, but unadjusted suicide rates per 100,000 population were higher at high (17.7) than at low (5.7) altitude. High and low altitude victims differed with respect to race, ethnicity, rural residence, intoxication, depressed mood preceding the suicide, firearm use and recent financial, job, legal, or interpersonal problems. Even after multivariate adjustment, there were significant differences in personal, mental health, and suicide characteristics among altitude groups. Compared to low altitude victims, high altitude victims had higher odds of having family or friends report of a depressed mood preceding the suicide (OR 1.78; 95%CI:1.46-2.17) and having a crisis within 2weeks before death (OR 2.00; 95%CI:1.63-1.46). Suicide victims at high and low altitudes differ significantly by multiple demographic, psychiatric, and suicide characteristics; these factors, rather than hypoxia or altitude itself, may explain increased suicide rates at high altitude.     

Examining classification criteria: a comparison of three cut score methods

This study compared 3 different methods of creating cut scores for a screening instrument, T scores, receiver operating characteristic curve (ROC) analysis, and the Rasch rating scale method (RSM), for use with the Behavioral and Emotional Screening System (BESS) Teacher Rating Scale for Children and Adolescents (Kamphaus & Reynolds, 2007). Using the BESS norm data set, we compared the methods across 7 classification indices. Additional information about accuracy was used with a subset of children who had been given a prior diagnosis for selected disorders. The results showed that the methods were generally in concordance, with similarities identified across methods. RSM and ROC analysis methods performed similarly, with both methods identifying the same optimal cut-point. The method based on T scores appeared to be more conservative, identifying a lower cut score as optimal.     

Cognitive culture: theoretical and empirical insights into social learning strategies

Research into social learning (learning from others) has expanded significantly in recent years, not least because of productive interactions between theoretical and empirical approaches. This has been coupled with a new emphasis on learning strategies, which places social learning within a cognitive decision-making framework. Understanding when, how and why individuals learn from others is a significant challenge, but one that is critical to numerous fields in multiple academic disciplines, including the study of social cognition.     

Visual threat detection during moderate- and high-intensity exercise

The aim of the study was to assess performance on a visual threat-detection task during concurrently performed vigorous exercise on a cycle ergometer. Thirty (15 female) participants completed a baseline condition of seated rest and then moderate- and high-intensity exercise. Moderate- and high-intensity exercise conditions were completed on the 2nd day in a counterbalanced order. During each exercise condition, participants responded to 3 × 3 picture matrices (256 trials in each condition) that contained discrepant fear-relevant and discrepant fear-irrelevant pictures (?hman, Flykt, & Esteves, 2001). Response accuracy was significantly greater, and reaction time was significantly faster, during moderate- and high-intensity exercise compared with the rest condition (ps < .001). The discrepant fear-relevant matrix type was detected significantly more accurately than a discrepant fear-irrelevant matrix (p < .001). The discrepant fear-relevant matrix was detected significantly faster than all other matrix types (p < .001). These results suggest that exercise at a moderate and high intensity may enhance the efficiency of visual detection of both threatening and nonthreatening targets.     

An inductive exploration of the social effectiveness construct space

ABSTRACT There is no agreement regarding the nature or number of dimensions that make up the social effectiveness domain. We inductively explore the relationships between a set of social effectiveness measures with the intention of identifying an initial set of dimensions. An exploratory factor analysis of the Social Competence Inventory (SCI, Schneider, 2001 ) resulted in the identification of four factors: Social Potency, Social Appropriateness, Social Emotional Expression, and Social Reputation. A joint factor analysis between the SCI and a set of extant measures resulted in the identification of the same four factors. A fifth factor emerged when a set of scales from an emotional intelligence measure was included in the analysis, suggesting that emotional intelligence is not captured within the common factor space defined by measures of social effectiveness. This study represents a first step in the establishment of a set of common social effectiveness dimensions.     

Diagnostic accuracy of the MMPI-2 Malingering Discriminant Function Index in the detection of malingering among inmates

The MMPI-2 Malingering Discriminant Function Index (M-DFI) was designed to detect malingerers educated about MMPI-2 validity indicators. However, given current attorney practices, the clinical utility of the M-DFI lies in its ability to detect examinees who are cautioned about the indicators. In this study, we compared 45 inmate simulators cautioned to avoid detection on the MMPI-2 with 46 psychiatric inmates who completed the MMPI-2 under standard instructions. Logistic regression analyses indicated that although the M-DFI performed better than several individual indicators, results were mixed for combinations of indicators, and the M-DFI did not outperform different sets of existing indicators. These findings support existing strategies to detect malingering on the MMPI-2. We discuss considerations concerning the clinical applicability of M-DFI.     

Staying or returning: Pre‐migration influences on the migration process of German migrants to New Zealand

Changes in migrants' backgrounds and societies sending and receiving migrants might increase adaptation issues and reduce retention. To enhance migrants' well‐being/health and their likelihood of staying it is necessary to gain an understanding of psychological and social factors that contribute to resilience and adaptation. This paper presents findings from a qualitative study that investigated the experiences, interpretations and actions of German migrant couples to New Zealand throughout the whole migration process to identify these factors. In depth, episodic interviews were conducted with four couples who decided to stay in New Zealand and four couples who decided to return to Germany. Interview data were complemented with participant observation. This paper provides insights into how the pre‐migration experiences, interpretations and actions of German migrants to New Zealand influenced their establishment, their interpretations and actions and consequently adaptation, well‐being/health and the decision whether to stay in New Zealand or to return to Germany. The findings illuminate the influence of psychological and social factors on migration experiences, interpretations and actions throughout the migration process. The paper offers some solutions for addressing the identified barriers to successful migration and integration into host societies. Copyright © 2008 John Wiley & Sons, Ltd.