Suicide among adolescents and young adults: a cross-national comparison of 34 countries

Few cross-national reports have examined suicide rates among adolescents and young adults. A survey of suicides among 15-24-year-olds in 34 of the wealthiest nations demonstrated that 15,555 youths killed themselves in a 1-year study period. Thirty-four percent of these suicides were firearm-related. Finland led the participating nations in total and firearm-related suicide rates. An association was found between divorce rates and youth suicide rates, firearm-related suicide among youths, and suicide rates among young males. For a smaller sample of countries, an association was found between firearm availability and firearm-related suicide rates among youths and suicide rates among young males.     

The locus of semantic priming in RSVP target search

At what stage does semantic priming affect accuracy in target search? In two experiments, participants viewed two streams of stimuli, each including a target word among distractors. Stimulus onset asynchronies (SOAs) between the targets (T1 and T2) ranged from 53 to 213 msec. A word semantically related to one or neither of the targets preceded each trial. In Experiment 1, participants were instructed to report both targets. Although more primed than unprimed targets were reported, there was no cost for unprimed words. A strong interaction between SOA and T1 versus T2 was found, but priming did not interact with either variable. In Experiment 2, only related targets were reported. Performance was similar to that for primed targets in Experiment 1. Semantic priming does not seem to modulate how attentional resources are initially allocated between targets, but instead affects a later stage of processing, the point at which a target word reaches lexical identification.     

Mother Teresa versus Ebenezer Scrooge: mortality salience leads proselfs to endorse self-transcendent values (unless proselfs are reassured)

Recently, Jonas, Schimel, Greenberg, and Pyszczynski demonstrated that mortality salience (MS) increased contributions to (an ingroup) charity (i.e., the Scrooge effect). The authors examined whether individual differences in social value orientations would moderate the Scrooge effect. In line with an Ebenezer shift hypothesis, proselfs were less likely than prosocials to endorse self-transcendent values in a dental pain control condition but were indistinguishable from prosocials in an MS condition as proselfs increased endorsement of self-transcendent values under MS (Experiments 1 and 2a). However, when participants gave their impressions of an unfavorable prosocial or a favorable proself prior to the MS manipulation, proselfs were again less likely than prosocials to endorse self-transcendent values (Experiments 2a and 2b), suggesting that proselfs are unlikely to transform into prosocials under conditions of MS when given reasons to disidentify with prosocial values or identify with proself values.     

Compatibility effects based on stimulus and response numerosity

Four choice reaction time experiments documented a stimulus-response (S-R) compatibility effect involving the numbers of stimuli and responses. In Experiment 1, the stimulus consisted of one or two tones, and the correct response was either one or two taps of a response key. Responses were much faster with a compatible S-R assignment, in which the number of taps matched the number of tones, than with an incompatible assignment in which these numbers mismatched. Experiments 2 and 3 replicated this effect, using visual stimuli and bimodal stimuli, respectively, suggesting that auditory/manual rhythmic compatibility is not essential to it. Experiment 4 showed that an analogous but smaller effect is obtained when stimuli are the digits 1 and 2. This new numerosity-based compatibility effect has general theoretical implications regarding the mechanisms responsible for compatibility effects and practical implications for interface design.     

Threshold estimation in two-alternative forced-choice (2AFC) tasks: the Spearman-Kärber method

The Spearman-K?rber method can be used to estimate the threshold value or difference limen in two-alternative forced-choice tasks. This method yields a simple estimator for the difference limen and its standard error, so that both can be calculated with a pocket calculator. In contrast to previous estimators, the present approach does not require any assumptions about the shape of the true underlying psychometric function. The performance of this new nonparametric estimator is compared with the standard technique of probit analysis. The Spearman-K?rber method appears to be a valuable addition to the toolbox of psychophysical methods, because it is most accurate for estimating the mean (i.e., absolute and difference thresholds) and dispersion of the psychometric function, although it is not optimal for estimating percentile-based parameters of this function.     

Effects of redundant visual stimuli on temporal order judgments

Four experiments were conducted in order to compare the effects of stimulus redundancy on temporal order judgments (TOJs) and reaction times (RTs). In Experiments 1 and 2, participants were presented in each trial with a tone and either a single visual stimulus or two redundant visual stimuli. They were asked to judge whether the tone or the visual display was presented first. Judgments of the relative onset times of the visual and the auditory stimuli were virtually unaffected by the presentation of redundant, rather than single, visual stimuli. Experiments 3 and 4 used simple RT tasks with the same stimuli, and responses were much faster to redundant than to single visual stimuli. It appears that the traditional speedup of RT associated with redundant visual stimuli arises after the stimulus detection processes to which TOJs are sensitive.     

A function of form: terror management and structuring the social world

Drawing on lay epistemology theory, the authors assessed a terror management analysis of the psychological function of structuring social information. Seven studies tested variations of the hypothesis that simple, benign interpretations of social information function, in part, to manage death-related anxiety. In Studies 1-4, mortality salience (MS) exaggerated primacy effects and reliance on representative information, decreased preference for a behaviorally inconsistent target among those high in personal need for structure (PNS), and increased high-PNS participants' preference for interpersonal balance. In Studies 5-7, MS increased high-PNS participants' preference for interpretations that suggest a just world and a benevolent causal order of events in the social world.     

A computer program for Spearman-Kärber and probit analysis of psychometric function data

PMETRIC is a computer program for the analysis of observed psychometric functions. It can estimate the parameters of these functions, using either probit analysis (a parametric technique) or the Spearman-Kärber method (a nonparametric one). For probit analysis, either a maximum likelihood or a minimum χ² criterion may be used for parameter estimation. In addition, standard errors of parameter estimates can be estimated via bootstrapping. The program can be used to analyze data obtained from either yes-no orm-alternative forced-choice tasks. To facilitate the use of PMETRIC in simulation work, an associated program, PMETGEN, is provided for the generation of simulated psychometric function data. Use of PMETRIC is illustrated with data from a duration discrimination task.     

Topiramate in the preventive treatment of episodic migraine: a combined analysis from pilot,double-blind,placebo-controlled trials

The safety and efficacy of medications for preventive treatment of migraine is the subject of current concern and investigation in health care. Two single-center, double-blind, placebo-controlled studies were conducted to evaluate the efficacy and safety of topiramate for migraine prophylaxis. Seventy patients with a diagnosis of migraine were randomly assigned to topiramate-treated and placebo groups. The studies consisted of a 4-week baseline phase, a 6-8 week titration, and 8-12 weeks of maintenance. Topiramate was titrated from an initial dose of 25 mg/day to a target dose of 100 mg BID. The primary efficacy measure, the mean 28-day migraine frequency, was lower in topiramate-treated patients than in the placebo group (3.2 versus 3.8, P=.001). Similarly, topiramate treatment resulted in a significantly greater mean reduction in migraine frequency than did placebo (1.55 versus 0.47, P=.001) and a significantly higher responder rate (35.3% versus 8.3%, P=.008). Paresthesia was the most common side effect reported with topiramate treatment. Other topiramate-associated adverse events included altered taste, memory impairment, diarrhea, and appetite suppression/weight loss. The rates of discontinuation were similar for the topiramate group (n=10) and the placebo group (n=8). These results suggest that topiramate is effective and well tolerated in the preventive treatment of migraine headaches.