Reliability estimates for the immediate and delayed memory tasks

The Immediate and Delayed Memory Tasks are variations of the Continuous Performance Test. While previous research with the tasks has focused on group performance across multiple blocks and sessions, reliability estimates have not been established. We estimated reliability (1) between blocks of a single testing session (N=106), (2) across four sessions within a single testing day (N=20), and (3) across sessions on four consecutive testing days (N=20). Analyses indicated that the primary variable of interest, i.e., commission of errors, showed acceptable reliability within and across testing periods.     

Temporal stability of the Wisconsin Card Sorting Test in a chronic traumatic brain injury sample

The aim of the present study was to investigate the temporal stability of the Wisconsin Card Sorting Test (WCST) in a clinical population with documented brain pathology, stable cognitive deficits, and for whom repeated testing is common: chronic severe traumatic brain injury (TBI). Participants were 34 patients at least 1 year post severe TBI living at a large residential rehabilitation facility. The WCST was administered in standard fashion with both the standard and 64-card versions scored. All derived scores with norms were examined. Results indicated acceptable temporal stability of most scores for both the standard and short WCST, although the stability of the WCST-64 was poorer than for the standard WCST. Three sets of significant change indices are provided for clinical use.     

What We Owe to the Global Poor

This essay defends an account of the duties to the global poor that is informed by the empirical question of what makes countries rich or poor, and that tends to be broadly in agreement with John Rawlss account in The Law of Peoples. I begin by introducing the debate about the sources of growth and explore its implications for duties towards the poor. Next I explore whether (and deny that) there are any further-reaching duties towards the poor. Finally, I ask about the moral foundations for the duties to the poor of the sort that earlier parts argue there are.     

Rare targets are rarely missed in correctable search

Failing to find a tumor in an x-ray scan or a gun in an airport baggage screening can have dire consequences, making it fundamentally important to elucidate the mechanisms that hinder performance in such visual searches. Recent laboratory work has indicated that low target prevalence can lead to disturbingly high miss rates in visual search. Here, however, we demonstrate that misses in low-prevalence searches can be readily abated. When targets are rarely present, observers adapt by responding more quickly, and miss rates are high. Critically, though, these misses are often due to response-execution errors, not perceptual or identification errors: Observers know a target was present, but just respond too quickly. When provided an opportunity to correct their last response, observers can catch their mistakes. Thus, low target prevalence may not be a generalizable cause of high miss rates in visual search.     

Visual attention as a predictor of on-road driving performance of older drivers

With increasing numbers of older drivers on Australian roads, it is important to determine the functional abilities most closely related to driving ability among older adults. To this end, 90 drivers aged from 60 to 91 completed a battery of psychological, visual, physical and cognitive tests, and a standardised on-road driving test. A computerised test of visual attention, devised specifically for the study, was the best predictor of on-road driving performance. Other abilities that made independent contributions to the prediction of driving performance were contrast sensitivity and visuospatial memory. These functional abilities provided a better prediction of driving performance than chronological age, reinforcing the argument that drivers should only have their driving tested when their functional abilities decline, rather than when they reach a particular age.     

Size matters: saccades during scene perception

We investigated the effect of image size on saccade amplitudes. First, in a meta-analysis, relevant results from previous scene perception studies are summarised, suggesting the possibility of a linear relationship between mean saccade amplitude and image size. Forty-eight observers viewed 96 colour scene images scaled to four different sizes, while their eye movements were recorded. Mean and median saccade amplitudes were found to be directly proportional to image size, while the mode of the distribution lay in the range of very short saccades. However, saccade amplitudes expressed as percentages of image size were not constant over the different image sizes; on smaller stimulus images, the relative saccades were found to be larger, and vice versa. In sum, and as far as mean and median saccade amplitudes are concerned, the size of stimulus images is the dominant factor. Other factors, such as image properties, viewing task, or measurement equipment, are only of subordinate importance. Thus, the role of stimulus size has to be reconsidered, in theoretical as well as methodological terms.     

Speech Planning at Turn Transitions in Dialog Is Associated With Increased Processing Load

Speech planning is a sophisticated process. In dialog, it regularly starts in overlap with an incoming turn by a conversation partner. We show that planning spoken responses in overlap with incoming turns is associated with higher processing load than planning in silence. In a dialogic experiment, participants took turns with a confederate describing lists of objects. The confederate’s utterances (to which participants responded) were pre‐recorded and varied in whether they ended in a verb or an object noun and whether this ending was predictable or not. We found that response planning in overlap with sentence‐final verbs evokes larger task‐evoked pupillary responses, while end predictability had no effect. This finding indicates that planning in overlap leads to higher processing load for next speakers in dialog and that next speakers do not proactively modulate the time course of their response planning based on their predictions of turn endings. The turn‐taking system exerts pressure on the language processing system by pushing speakers to plan in overlap despite the ensuing increase in processing load.     

Models and scientific representations or: who is afraid of inconsistency?

I argue that if we make explicit the role of the user of scientific representations not only in the application but also in the construction of a model or representation, then inconsistent modeling assumptions do not pose an insurmountable obstacle to our representational practices.