Separating response‐execution bias from decision bias: Arguments for an additional parameter in Ratcliff's diffusion model

Diffusion model data analysis permits the disentangling of different processes underlying the effects of experimental manipulations. Estimates can be provided for the speed of information accumulation, for the amount of information used to draw conclusions, and for a decision bias. One parameter describes the duration of non‐decisional processes including the duration of motor‐response execution. In the default diffusion model, it is implicitly assumed that both responses are executed with the same speed. In some applications of the diffusion model, this assumption will be violated. This will lead to biased parameter estimates. Consequently, we suggest accounting explicitly for differences in the speed of response execution for both responses. Results from a simulation study illustrate that parameter estimates from the default model are biased if the speed of response execution differs between responses. A second simulation study shows that large trial numbers (N>1,000) are needed to detect whether differences in response‐execution times are based on different execution times.     

Medikamentöse Therapieoptionen bei sekundär progredienter Multipler Sklerose

Anders als bei Patienten mit schubf?rmiger Multipler Sklerose, insbesondere jenen, die erst kurze Zeit erkrankt sind, sind unsere therapeutischen M?glichkeiten für Patienten mit sekund?r chronisch progredienter Multipler Sklerose leider noch immer nicht ausreichend. Dies bedeutet erstens, dass wir unsere zur Verfügung stehenden Therapien frühzeitig im Verlauf der Erkrankung einsetzen müssen, um überhaupt erst einen übergang in eine sekund?re Progredienz zu verhindern. Andererseits kann man, wenn ein Patient bereits in der sekund?r progredienten Phase ist, durch sorgf?ltig überlegten Einsatz Krankheitsmodifizierender medikament?ser Therapien, symptomatischer Therapien und Rehabilitation eine lange Stabilisierung der Multiplen Sklerose bei guter Lebensqualit?t erreichen.     

The facing bias in biological motion perception: Effects of stimulus gender and observer sex

Under orthographic projection, biological motion point-light walkers offer no cues to the order of the dots in depth: Views from the front and from the back result in the very same stimulus. Yet observers show a bias toward seeing a walker facing the viewer (Vanrie, Dekeyser, & Verfaillie, 2004). Recently, we reported that this facing bias strongly depends on the gender of the walker (Brooks et al., 2008). The goal of the present study was, first, to examine the robustness of the effect by testing a much larger subject sample and, second, to investigate whether the effect depends on observer sex. Despite the fact that we found a significant effect of figure gender, we clearly failed to replicate the strong effect observed in the original study. We did, however, observe a significant interaction between figure gender and observer sex.     

The structure of the relationship between attention and intelligence

The relationship between attention and general intelligence was investigated considering the different types of attention: alertness, sustained attention, focused attention, attentional switching, divided attention, attention according to the supervisory attentional system, attention as inhibition, spatial attention, attention as planning, interference, attention as arousal, and attention according to the assessment tradition. In a sample of 197 participants the relationship of attention and intelligence was investigated by means of structural equation modeling. The results revealed that each type of attention was substantially related to intelligence on the latent level. Furthermore, a high degree of overlap in predicting intelligence was observed for the various types of attention. Comprehensive models based on resources theory and Posner's dimensions were also investigated. The best model of the relationship between attention and intelligence included two first-order and one second-order latent variables of attention and one of intelligence. It predicted 32% of the variance of intelligence.     

The Changing Values of Children and Preferences Regarding Family Size in South Africa

Cette recherche élargit à un contexte africain avec la problématique suivante les études en cours sur les relations entre les générations et les valeurs attribuées aux enfants: dans quelle mesure la structure des valeurs projetées sur les enfants (VOC) repérée dans des études antérieures peut‐elle être retrouvée en Afrique du Sud et quelles sont les préférences des femmes concernant la taille des familles petite, nombreuse et idéale. L’échantillon était constitué de trois cohortes de femmes noires sud‐africaines originaires de la province de Limpopo. Des analyses factorielles ont montré que les dimensions de la VOC apparue en Afrique du Sud étaient un agrégat de différentes valeurs. Ont été isolées comme dimensions relatives au désir d’enfants Social/Emotionnel et Traditionnel/Utilitaire. Pour ce qui est des motifs expliquant le choix de ne pas avoir d’enfants sont apparus l’enfant comme source de contraintes et les contraintes que constitue le fait d’avoir un enfant. Les comparaisons entre les générations montrent des variations dans l’importance des dimensions des valeurs accordées aux enfants et dans les préférences concernant la taille de la famille. Les valeurs dont les enfants sont porteurs pour les jeunes mères étaient liées au nombre d’enfants que ces femmes avaient et à leurs préférences relatives à la taille de la famille. La discussion sur les résultats tient compte de l’évolution du contexte sociopolitique de l’Afrique du Sud. This study extends the ongoing studies on values of children and intergenerational relations into an African context with the following key questions: To what extent can the structure of values of children (VOC) identified in previous studies be found in South Africa and what are women's preferences regarding the size of small, large, and ideal families? The sample consisted of three cohorts of Black South African women from the Limpopo Province. Factor analyses showed that the dimensions of VOC found in South Africa are a conglomeration of different values. Identified dimensions were Social/Emotional and Traditional/Utilitarian with respect to reasons for wanting children. Regarding reasons for not wanting children, Child as Source of Constraints and Constraints to Have a Child were identified. Intergenerational comparisons showed variations in the importance of value of children dimensions and in preferences regarding family size. Values of children of younger mothers were related to the number of children these women had and to their preferences regarding family size. The findings are discussed within the changing socio‐political context of South Africa.     

CONFESSIONS OF A PRACTICING NATURALISTIC THEIST: A RESPONSE TO HARDWICK,PEDERSON, AND PETERSON

Abstract. In my response to the comments of Charley Hardwick, Ann Pederson, and Greg Peterson, I continue the narrative, confessional mode of my writing in Dancing with the Sacred. First, I sketch some methodological decisions underlying my naturalistic, evolutionary, practical theology. I then respond to the encouraging suggestions of my commentators by further developing my ideas about naturalism, mystery, creativity as God, the place of ecological responsibility in my thinking, sin, and eschatology. I offer suggestions as to how I might widen the practical applications of my theology beyond environmental and medical ethics to other areas of moral responsibility in relation to the creative process. I do all this with much appreciation for the care and careful critical reflection that my commentators have devoted to my thinking.     

Looking back versus looking ahead: framing of time and work at different stages of a project

Progress on a well‐defined project can be described along a task dimension in terms of amount done, or as amount of work still to be completed. Time‐limited projects can also be described on a temporal dimension in terms of time spent versus time left. Five experiments are reported showing that such frames have predictable implications for speakers as well as for listeners: Statements by a team leader about time spent and work left are perceived as suggestions to “hurry up,” whereas complementary statements about work done and time left indicate that the team can take it more easy. The first set of statements further implies that the team is behind schedule, whereas the last two statements suggest that the team is ahead of the plan. In line with this, speakers preferred work done and time left statements when they were ahead of schedule, but not when they were behind. “Hurry up” and “behind schedule” interpretations were also shown to be dependent upon stage, being more prominent in the final stages than during the initial stages of a project. Copyright © 2005 John Wiley & Sons, Ltd.     

Motivational sources of confirmation bias in criminal investigations: the need for cognitive closure

In two experiments, criminal investigators (N = 50) and undergraduate students (N = 68) read a set of facts from the preliminary investigation of a homicide case. Participants' initial hypothesis regarding the crime was manipulated by providing background information implying that the prime suspect had a jealousy motive or that there might be an alternative perpetrator. Students displayed a framing effect, such that guilt was ascribed to the prime suspect only when a potential motive was presented, whereas investigators did so regardless of hypothesis, thus being less sensitive to alternative interpretations. Investigators' need for cognitive closure (NFC) moderated the effect of the hypothesis on perceptions of the strength of the evidence against the prime suspect; high (v low) NFC investigators were less likely to acknowledge inconsistencies in the material when presented with a potential motive, but were more likely to do so when made aware of the possibility of an alternative perpetrator. Interpretations are somewhat clouded by the fact that dispositional NFC did not seem to affect in a consistent manner participants' motivation toward the experimental task. Copyright © 2005 John Wiley & Sons, Ltd.     

Hierarchical Multinomial Processing Tree Models: A Latent-Class Approach

Multinomial processing tree models are widely used in many areas of psychology. Their application relies on the assumption of parameter homogeneity, that is, on the assumption that participants do not differ in their parameter values. Tests for parameter homogeneity are proposed that can be routinely used as part of multinomial model analyses to defend the assumption. If parameter homogeneity is found to be violated, a new family of models, termed latent-class multinomial processing tree models, can be applied that accommodates parameter heterogeneity and correlated parameters, yet preserves most of the advantages of the traditional multinomial method. Estimation, goodness-of-fit tests, and tests of other hypotheses of interest are considered for the new family of models. The author thanks Bill Batchelder, Edgar Erdfelder, Thorsten Meiser, and Christoph Stahl for helpful comments on a previous version of this paper. The author is also grateful to Edgar Erdfelder for making available the data set analyzed in this paper.     

Application of virtual reality graphics in assessment of concussion.

Abnormal balance in individuals suffering from traumatic brain injury (TBI) has been documented in numerous recent studies. However, specific mechanisms causing balance deficits have not been systematically examined. This paper demonstrated the destabilizing effect of visual field motion, induced by virtual reality graphics in concussed individuals but not in normal controls. Fifty five student-athletes at risk for concussion participated in this study prior to injury and 10 of these subjects who suffered MTBI were tested again on day 3, day 10, and day 30 after the incident. Postural responses to visual field motion were recorded using a virtual reality (VR) environment in conjunction with balance (AMTI force plate) and motion tracking (Flock of Birds) technologies. Two experimental conditions were introduced where subjects passively viewed VR scenes or actively manipulated the visual field motion. Long-lasting destabilizing effects of visual field motion were revealed, although subjects were asymptomatic when standard balance tests were introduced. The findings demonstrate that advanced VR technology may detect residual symptoms of concussion at least 30 days post-injury.