Biomedical subjects

Yehoshua Tsal

Publications and source records attributed to Yehoshua Tsal.

6 recordsLinked to original sources

PubMed2006

The attentional white bear phenomenon: the mandatory allocation of attention to expected distractor locations.

The authors devised a prestimulus-probe method to assess the allocation of attention as a function of participants' top-down expectancies concerning distractor and target locations. Participants performed the flanker task, and distractor locations remained fixed. On some trials, instead of the flanker display, either 2 simultaneous dots or a horizontal line appeared. The dot in the expected distractor location was perceived to occur before the dot in the expected empty location, and the line appeared to extend from the expected distractor location to the expected empty location, suggesting that attention is allocated to expected distractor locations prior to stimulus onset. The authors propose that a process-all mechanism guides attention to expected locations of all stimuli regardless of task demands and that this constitutes a major cause for failures of selective attention.

Adult↗

PubMed2005

Localization judgments under various levels of attention.

We investigated the effects of attention on localization with two converging manipulations of attention. The results indicated that whereas attention improved localization, minimally attended stimuli were nonetheless localized fairly accurately. The distributions of localization responses around peripheral stimuli were asymmetric, with a greater dispersion along the axis linking fixation to stimulus location relative to its perpendicular axis. We propose that the unattended field comprises attentional receptive fields that are mediated by coarse location detectors. We speculate that attention produces fine localization by facilitating computations that integrate the relative activation of overlapping detectors.

Attention↗

PubMed2005

The lengthening effect revisited: a reply to Prinzmetal and Wilson (1997) and Masin (1999).

In the present study, the lengthening phenomenon (Tsal & Shalev, 1996), namely, the increase in perceived length of unattended lines, was reexamined in light of criticisms by Prinzmetal and Wilson (1997) and Masin (1999). Prinzmetal and Wilson suggested that the effect was not due to attentional factors but to the spatial interaction between the attended line and the cue used to direct attention. We have replicated the lengthening effect when both attended and unattended lines are preceded by cues at a nearby location, showing that the effect is not caused by spatial cues per se, but instead reflects an inherent property of the attentional system. Masin argued that the lengthening effect is not robust, because it occurs for some but not for all participants. In the present study, the lengthening effect was highly reliable, occurring for each participant for a variety of line lengths.

Attention↗

PubMed2003

Does a salient distractor capture attention early in processing?

Kim and Cave (1999) used spatial probes in order to measure the effects of bottom-up and top-down factors on the allocation of spatial attention over time. Subjects searched for a target with a unique shape, with a uniquely colored distractor present on each trial. The singleton distractor captured attention early in processing, whereas attention homed in on the target's location later on. Kim and Cave (1999) concluded that top-down factors cannot prevent the presence of a salient distractor from delaying target selection. The present study tested the idea that such results were obtained only because subjects adopted the strategy of searching for the most salient item. Kim and Cave's (1999) finding was replicated in Experiment 1. In Experiment 2, instead of a feature search, subjects performed a conjunction search-that is, a task that could not be performed using a salience-based strategy. Probe response times were longest at the salient distractor's location at both the short and the long stimulus onset asynchronies. These results suggest that, early in processing, top-down factors can exert their influence and prevent the capture of attention by a salient distractor.

Attention↗

PubMedDate not supplied

The wide attentional window: a major deficit of children with attention difficulties.

The present study assessed visual selective attention in children with attention difficulties compared to age-matched, typically achieving children. We used the flanker task, which requires participants to respond to a central target flanked by distractors, and the feature and conjunction visual search, which requires participants to search for a predesignated target embedded among a variable number of distractors. The results showed that children with attention difficulties encountered major problems only when responding to a central target flanked by adjacent incongruent distractors and when searching for a conjunctive target in a high-density display. These results suggest that children with attention difficulties have a characteristic inability to restrict visual attention to a limited spatial area so as to selectively process relevant information while effectively ignoring distracting information.

Attention Deficit Disorder with Hyperactivity↗

PubMedDate not supplied

The diversity of attention deficits in ADHD: the prevalence of four cognitive factors in ADHD versus controls.

The performance of participants with attention-deficit/hyperactivity disorder (ADHD) relative to control participants was measured on four tasks uniquely assessing the functions of selective attention, executive attention, sustained attention, and orienting of attention. The results showed that deficits in sustained attention were the most pronounced, characterizing most participants with ADHD and deficits in each of the other three functions characterized more than half of these participants. Different participants with ADHD revealed different clusters of attentional deficits. These results call for a revision of leading theories of ADHD that identify the core of the pathology as a sole deficit in executive functions.

Attention↗