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Biomedical subjects

Jan Theeuwes

Publications and source records attributed to Jan Theeuwes.

7 recordsLinked to original sources
PubMed2003

Attentional capture within and between objects.

The present study addressed the question whether attentional capture by abrupt onsets is affected by object-like properties of the stimulus field. Observers searched for a target circle at one of four ends of two solid rectangles. In the focused attention condition the location of the upcoming target was cued by means of a central arrowhead, whereas in the divided attention condition, the target location was not cued. Irrelevant abrupt onsets could appear either within the attended or within the non-attended object. The results showed that in the focused attention condition, onsets ceased to capture attention irrespective of whether the onset appeared within an attended object or within a non-attended object.

Adolescent↗
PubMed2003

Attentional and oculomotor capture with static singletons.

Previous research has shown that in visual search static singletons have the ability to capture attention (Theeuwes, 1991a, 1992). The present study investigated whether these singletons also have the ability to capture the eyes. Participants had to make an eye movement and respond manually to a shape singleton while a color singleton was present. When participants searched for a unique shape while a unique color singleton was present there was strong attentional and oculomotor capture (Experiment 1). However, when participants searched for a specific-shape singleton (a green circle) when a specific-color singleton (a red element) had to be ignored, there was attentional capture but no oculomotor capture (Experiment 2). The results suggest that an attentional set for a specific feature value defining both the target and the distractor (as in Experiment 2) allows such a fast disengagement of attention from the location of the distractor that a saccade execution to that location is prevented.

Attention↗
PubMed2002

Oculomotor capture and Inhibition of Return: evidence for an oculomotor suppression account of IOR.

Previous research has shown that when subjects search for a particular target object the sudden appearance of a new object captures the eyes on a large proportion of trials. The present study examined whether the onset affects the oculomotor system even when the eyes move directly towards the target. Using a modified version of the oculomotor paradigm (see Theeuwes, Kramer, Hahn, & Irwin, 1998) we show that when the eyes moved to the target object, subsequent saccades were inhibited from moving to a location at which a new object had previously appeared (inhibition-of-return; IOR). Whether or not a saccade to the onset was executed had no effect on the size of the inhibition. In particular conditions, the trajectories of saccades to the target objects were slightly curved in the opposite direction of the onset. The data are interpreted in the context of a novel hypothesis regarding oculomotor IOR.

Adult↗
PubMed2002

Programming of endogenous and exogenous saccades: evidence for a competitive integration model.

Participants were required to make a saccade to a uniquely colored target while ignoring the presentation of an onset distractor. The results provide evidence for a competitive integration model of saccade programming that assumes endogenous and exogenous saccades are programmed in a common saccade map. The model incorporates a lateral interaction structure in which saccade-related activation at a specific location spreads to neighboring locations but inhibits distant locations. In addition, there is top-down, location-specific inhibition of locations to which the saccade should not go. The time course of exogenous and endogenous activation in the saccade map can explain a variety of eye movement data, including endpoints, latencies, and trajectories of saccades and the well-known global effect.

Analysis of Variance↗
PubMed2002

Relation between glare and driving performance.

The present study investigated the effects of discomfort glare on driving behavior. Participants (old and young; U. S. and Europeans) were exposed to a simulated low-beam light source mounted on the hood of an instrumented vehicle. Participants drove at night in actual traffic along a track consisting of urban, rural, and highway stretches. The results show that the relatively low glare source caused a significant drop in detecting simulated pedestrians along the roadside and made participants drive significantly slower on dark and winding roads. Older participants showed the largest drop in pedestrian detection performance and reduced their driving speed the most. The results indicate that the deBoer rating scale, the most commonly used rating scale for discomfort glare, is practically useless as a predictor of driving performance. Furthermore, the maximum U. S. headlamp intensity (1,380 cd per headlamp) appears to be an acceptable upper limit.

Adolescent↗
PubMed2002

Irrelevant singletons capture attention: evidence from inhibition of return.

Previous research has shown that a salient feature singleton may capture attention in a stimulus-driven, bottom-up fashion (e.g., Theeuwes, 1992,1994b). This conclusion has been challenged by others claiming that the observed attentional capture by irrelevant singletons may not be stimulus driven but due to top-down attentional control settings and/or nonspatial filtering costs. In the present study, we show that inhibition of return (IOR) occurs at the location of an irrelevant singleton. Participants were slower to detect a target presented at the location of the irrelevant singleton, relative to other locations. Since IOR can be observed only as a result of an exogenous, stimulus-driven shift of spatial attention, it isun-likely that top-down control settings and/or nonspatial filtering costs played a role. In line with earlier claims, the present findings provide strong evidence that salient singletons capture spatial attention in a purely bottom-up way.

Adolescent↗