Parallel,exhaustive processing underlies logarithmic search functions: Visual search with cortical magnification

Our lab recently found evidence that efficient visual search (with a fixed target) is characterized by logarithmic Reaction Time (RT) × Set Size functions whose steepness is modulated by the similarity between target and distractors. To determine whether this pattern of results was based on low-level visual factors uncontrolled by previous experiments, we minimized the possibility of crowding effects in the display, compensated for the cortical magnification factor by magnifying search items based on their eccentricity, and compared search performance on such displays to performance on displays without magnification compensation. In both cases, the RT × Set Size functions were found to be logarithmic, and the modulation of the log slopes by target–distractor similarity was replicated. Consistent with previous results in the literature, cortical magnification compensation eliminated most target eccentricity effects. We conclude that the log functions and their modulation by target–distractor similarity relations reflect a parallel exhaustive processing architecture for early vision.     

Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance

Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS—namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.     

Age-related effects in inter-trial inhibition of attention

Young and older adults indentified the shape of a color oddball in a visual search task, and both showed faster and more accurate responses when the distractor color was passively viewed in the preceding target-absent trial than when the target color was previewed. This inter-trial effect, known as the distractor previewing effect (DPE), reflects an attentional bias that prevents attention from focusing on recently inspected features that failed to produce a target. The results showed that the DPE pattern was preserved across the lifespan, and that the age-related increase in the magnitude of the DPE appeared rooted in age-related slowing, suggesting substantial sparing of this inhibitory effect in old age.     

Weighing the past and the future in decision making

Prior irreversible investments of money, time, or effort referred to as sunk costs frequently lead to decisions to continue a chosen course of action despite that this is irrational. With the aim of demonstrating that such escalation of commitment is a special case of a more general phenomenon, two experiments were carried out employing undergraduates as participants. Experiment 1 showed for fictitious personal and business investment scenarios that both prior losses and gains (sunk outcomes) affected choices to continue or discontinue the investment. In Experiment 2 the effect of sunk outcomes was reduced although not eliminated by a monetary bonus that in one condition depended on the future outcomes of the second gamble in two-stage gambles, in another condition on the future returns in personal investment scenarios. In support of a more inclusive theory subsuming escalation of commitment, the decisions were affected by both past and future outcomes and both gains and losses.     

What you see is what you get: functional equivalence of a perceptually filled-in surface and a physically presented stimulus

A perceptually filled-in surface, such as occurs during sustained attention to a peripheral stimulus (Troxler fading), can be functionally equivalent to a physically presented stimulus. Observers failed to detect probes that were presented in the location of a filled-in surface that had the same surface attributes as the probes; this was true even though, physically, the probes contrasted with the background. Probe stimuli with surface characteristics different from those of the filled-in surface were detected more often, though not quite as often as when there was no filled-in surface. Together, these findings support the idea that there are two components in perceptual filling: a neural filling-in component and a sustained-attention component, which actively suppresses perceptual processing at the filled-in location. More broadly, they illustrate the interplay of basic visual mechanisms in the creation and representation of visual surfaces and in the coding and detection of changes to these surfaces.     

Fruitful visual search: Inhibition of return in a virtual foraging task

Inhibition of return (IOR) has long been viewed as a foraging facilitator in visual search. We investigated the contribution of IOR in a task that approximates natural foraging more closely than typical visual search tasks. Participants in a fully immersive virtual reality environment manually searched an array of leaves for a hidden piece of fruit, using a wand to select and examine each leaf location. Search was slower than in typical IOR paradigms, taking seconds instead of a few hundred milliseconds. Participants also made a speeded response when they detected a flashing leaf that either was or was not in a previously searched location. Responses were slower when the flashing leaf was in a previously searched location than when it was in an unvisited location. These results generalize IOR to an approximation of a naturalistic visual search setting and support the hypothesis that IOR can facilitate foraging. The experiment also constitutes the first use of a fully immersive virtual reality display in the study of IOR.     

Spiritual care as eHealth: a systematic review

A systematic review was undertaken of the literature on the use of the Internet and other information and communication technologies (ICT's) in the provision and support of religious and spiritual care in healthcare. Indexes such as Medline, PsychoINFO and Proquest Religion were searched. The review found little systematic study of the effectiveness of the Internet and other ICT's in religious and spiritual care. It is believed that the results of this review provide a basis for promise spiri care in the further explora of the potential and of ICT's for tual healthcare.     

Avoiding the death risk of avoiding a dread risk: the aftermath of March 11 in Spain

Abstract-After the airplane attacks of September 11, 2001, in the United States, many Americans drove instead of flying, to avoid the risk of terrorism. As a result, there were extra car accidents in which many people died. This study tested whether a similar effect occurred in Spain after the train bombings of March 11, 2004, in Madrid. Data on train travel, highway traffic, and fatal highway accidents were analyzed for the months immediately following March 11. Results show that, like Americans, Spaniards avoided the dread risk of terror attacks, but unlike Americans, they did not confront the death risk of fatal accidents instead. A sociopolitical interpretation for these findings is offered.