Combining speed and accuracy to assess error-free cognitive processes

Both the speed and accuracy of responding are important measures of performance. A well-known interpretive difficulty is that participants may differ in their strategy, trading speed for accuracy, with no change in underlying competence. Another difficulty arises when participants respond slowly and inaccurately (rather than quickly but inaccurately), e.g., due to a lapse of attention. We introduce an approach that combines response time and accuracy information and addresses both situations. The modeling framework assumes two latent competing processes. The first, the error-free process, always produces correct responses. The second, the guessing process, results in all observed errors and some of the correct responses (but does so via non-specific processes, e.g., guessing in compliance with instructions to respond on each trial). Inferential summaries of the speed of the error-free process provide a principled assessment of cognitive performance reducing the influences of both fast and slow guesses. Likelihood analysis is discussed for the basic model and extensions. The approach is applied to a data set on response times in a working memory test. The authors wish to thank Roger Ratcliff, Christopher Chabris, and three anonymous referees for their helpful comments, and Aureliu Lavric for providing the data analyzed in this paper.     

An implicit test of the associations between children and sex in pedophiles

Pedophiles are motivated to disguise their thoughts and feelings about their sexual beliefs and attraction toward children. New developments using implicit measures of associations have been successful in accessing socially stigmatic beliefs, even in cases in which the participant is resistant to this disclosure. Using an implicit measure, the authors show that pedophiles have an association between children and sex, whereas nonpedophilic offenders have an association between adults and sex. The task can therefore identify a core cognitive abnormality that may underpin some pedophilic deviant sexual behavior.     

Different strategies for using motion-in-depth information in catching

Previous studies on ball catching have had the limitation that the catcher was restricted to lateral hand movements. The authors investigated catching behavior in the more natural situation in which hand movements were unconstrained. Movements of the hand were tracked as participants tried to "catch" an approaching ball simulated with changing size and/or changing disparity. Participants used 1 of 2 distinct interception strategies: (a) a "cutting-off" strategy where time to passage (TTP) information was used to guide movements of the hand in depth such that the ball was caught farther in front of the face when the ball was approaching more slowly and (b) a "waiting" strategy where the hand was moved along a frontoparallel plane that was constant across ball trajectories and speeds. Cue dissociation and selective adaptation manipulations demonstrated that the catcher's estimates of TTP and crossing distance were based on a combination of binocular and monocular information.     

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.     

Attending to the execution of a complex sensorimotor skill: expertise differences, choking, and slumps

A simulated baseball batting task was used to compare the relative effects of attending to extraneous information (tone frequency) and attending to skill execution (direction of bat movement) on performance and swing kinematics and to evaluate how these effects differ as a function of expertise. The extraneous dual task degraded batting performance in novices but had no significant effect on experts. The skill-focused dual task increased batting errors and movement variability for experts but had no significant effect on novices. For expert batters, accuracy in the skill-focused dual task was inversely related to the current level of performance. Expert batters were significantly more accurate in the skill-focused dual task when placed under pressure. These findings indicate that the attentional focus varies substantially across and within performers with different levels of expertise.     

Direct observations of pandanus-tool manufacture and use by a New Caledonian crow (<Emphasis Type="Italic">Corvus moneduloides</Emphasis>)

New Caledonian crows are reported to have impressive pandanus-tool manufacture abilities. These claims are based on an extensive artefact record. However, inferring behavioural and cognitive abilities without direct observation of tool manufacture is problematic. Here we report (and document on video) direct observations of a crow making and using stepped pandanus tools at Pic Ningua. We observed (1) a bias for making tools on left edges consistent with that previously found at the site, (2) faithful manufacture of a stepped design with high overall congruence in the shapes of tools, (3) the use of convergent rips to first form the tapered end working away from the trunk then the wide end working towards the trunk, (4) appropriate functional use of stepped tools by use of the leaf-edge barbs to hook food from holes, and (5) consistent holding of tools on the left side of its head when using them. Our observations verify most of the claims based on the artefact record, but the crows exact manufacture technique was slightly different to that inferred previously.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

ESID,Dissemination, and Community Psychology: A Case of Partial Implementation?

Dissemination, the second stage of Experimental Social Innovation and Dissemination (ESID) is a critical, if not defining, element of this social change model. This paper attempts to assess the extent to which community psychology has adopted and implemented ESID's dissemination focus in its training and publications. We identify four levels of commitment to dissemination: dissemination advocate, dissemination activist, dissemination researcher, and experimental dissemination researcher. Content analyses of textbooks, journal publications, and conference papers and a brief survey of doctoral training in the field were conducted. Findings suggest that the dissemination aspects of ESID have been modestly and partially implemented within the field. That is, although there is some evidence of a commitment to dissemination practice (advocate, activist), there is much less evidence of a commitment to dissemination research. The implications of these findings for the effectiveness of the ESID model and for training and practice in community psychology are discussed.     

Changes in behavior and behavioral intentions among middle-age women: results from an osteoporosis prevention program

The purpose of this study was to evaluate changes in behaviors and behavioral intentions that occurred among 342 middle-age women (M age 49.5 yr.) after participating in an Osteoporosis Prevention Program. The valid and reliable Osteoporosis Preventing Behaviors Survey (developed by Doheny and Sedlak) and a survey developed for this work were measures. Significant changes in behaviors were reported, especially increases in weight-bearing physical activity, dairy product intake, and decreases in consumption of caffeine-containing beverages. Many subjects reported intentions to increase physical activity and calcium intake. An Osteoporosis Prevention Program may help promote osteoporosis prevention behaviors, but intents must be followed up to check actual change.