Millisecond accuracy video display using OpenGL under Linux

To measure people’s reaction times to the nearest millisecond, it is necessary to know exactly when a stimulus is displayed. This article describes how to display stimuli with millisecond accuracy on a normal CRT monitor, using a PC running Linux. A simple C program is presented to illustrate how this may be done within X Windows using the OpenGL rendering system. A test of this system is reported that demonstrates that stimuli may be consistently displayed with millisecond accuracy. An algorithm is presented that allows the exact time of stimulus presentation to be deduced, even if there are relatively large errors in measuring the display time.     

Differential developmental trajectories for egocentric, environmental and intrinsic frames of reference in spatial memory

We studied the development of spatial frames of reference in children aged 3-6 years, who retrieved hidden toys from an array of identical containers bordered by landmarks under four conditions. By moving the child and/or the array between presentation and test, we varied the consistency of the hidden toy with (i) the body, and (ii) the testing room. The toy's position always remained consistent with (iii) the array and bordering landmarks. We found separate, additive performance advantages for consistency with body and room. These effects were already present at 3 years. A striking finding was that the room effect, which implies allocentric representations of the room and/or egocentric representations updated by self-motion, was much stronger in the youngest children than the body effect, which implies purely egocentric representations. Children as young as 3 years therefore had, and greatly favoured, spatial representations that were not purely egocentric. Viewpoint-independent recall based only on the array and bordering landmarks emerged at 5 years. There was no evidence that this later-developing ability, which implies object-referenced (intrinsic) representations, depended on verbal encodings. These findings indicate that core components of adult spatial competence, including parallel egocentric and nonegocentric representations of space, are present as early as 3 years. These are supplemented by later-developing object-referenced representations.     

What is Genetic Information,and why is it Significant? A Contextual,Contrastive, Approach

abstract Is genetic information of special ethical significance? Does it require special regulation? There is considerable contemporary debate about this question (the ‘genetic exceptionalism’ debate). ‘Genetic information’ is an ambiguous term and, as an aid to avoiding conflation in the genetic exceptionalism debate, a detailed account is given of just how and why ‘genetic information’ is ambiguous. Whilst ambiguity is a ubiquitous problem of communication, it is suggested that ‘genetic information’ is ambiguous in a particular way, one that gives rise to the problem of ‘significance creep’ (i.e., where claims about the significance of certain kinds of genetic information in one context influence our thinking about the significance of other kinds of genetic information in other contexts). A contextual and contrastive methodology is proposed: evaluating the significance of genetic information requires us to be sensitive to the polysemy of ‘genetic information’ across contexts and then examine the contrast in significance (if any) of genetic, as opposed to nongenetic, information within contexts. This, in turn, suggests that a proper solution to the regulatory question requires us to pay more attention to how and why information, and its acquisition, possession and use, come to be of ethical significance.     

Generation and context memory

Generation enhances memory for occurrence but may not enhance other aspects of memory. The present study further delineates the negative generation effect in context memory reported in N. W. Mulligan (2004). First, the negative generation effect occurred for perceptual attributes of the target item (its color and font) but not for extratarget aspects of context (location and background color). Second, nonvisual generation tasks with either semantic or nonsemantic generation rules (antonym and rhyme generation, respectively) produced the same pattern of results. In contrast, a visual (or data-driven) generation task (letter transposition) did not disrupt context memory for color. Third, generating nonwords produced no effect on item memory but persisted in producing a negative effect on context memory for target attributes, implying that (a) the negative generation effect in context memory is not mediated by semantic encoding, and (b) the negative effect on context memory can be dissociated from the positive effect on item memory. The results are interpreted in terms of the processing account of generation. The original, perceptual-conceptual version of this account is too narrow, but a modified processing account, based on a more generic visual versus nonvisual processing distinction, accommodates the results.     

Emotional expressions forecast approach-avoidance behavior

The contention that basic behavioral intentions are forecasted by emotional expressions has received surprisingly little empirical support. We introduce a behavioral task that gauges the speed with which movement of angry and fearful faces (toward or away from an expressor's gaze) are accurately detected. In two studies we found that perceivers were faster to correctly detect approaching anger faces (i.e., faces that moved in the direction of their own gaze). The opposite, however, was not true for fear expressions. These findings offer evidence that, at least for anger displays, the basic behavioral intent to approach is strongly transmitted and at very low-levels of processing, even priming congruent behavioral responses in observers. The null results for fear faces may indicate that these signal a “freezing” response or behavioral inhibition rather than flight per se. The results of this work are discussed in relation to contemporary theories of emotion.     

Genetics and delusional disorder

This article gives an overview of genetic research approaches and their application to delusional disorder. Most studies have been based on small samples and have had other methodological limitations, so it is not clear whether there is a genetic contribution to the aetiology of delusional disorder. It is unlikely that delusional disorder is strongly related genetically to affective disorder or schizophrenia, but more subtle relationships cannot be ruled out. The rarity of multiply affected families prohibits linkage studies and, to date, molecular genetic investigations have been mainly limited to small association studies of dopamine receptor polymorphisms. A range of considerably larger, epidemiologically rigorous studies is required, but the uncommonness and other features of the disorder put strong limitations on the prospects for ascertaining adequate samples.     

Large-scale investigation of the role of trait activation theory for understanding assessment center convergent and discriminant validity

This study used trait activation theory as a theoretical framework to conduct a large-scale test of the interactionist explanation of the convergent and discriminant validity findings obtained in assessment centers. Trait activation theory specifies the conditions in which cross-situationally consistent and inconsistent candidate performances are likely to occur. Results obtained by aggregating correlations across 30 multitrait-multimethod matrices supported the propositions of trait activation theory, shedding a more positive light on the construct validity puzzle in assessment centers. Overall, convergence among assessment center ratings was better between exercises that provided an opportunity to observe behavior related to the same trait, and discrimination among ratings within exercises was generally better for dimensions that were not expressions of the same underlying traits. Implications for assessment center research and practice are discussed.