Biomedical subjects

Peter Wühr

Publications and source records attributed to Peter Wühr.

4 recordsLinked to original sources

PubMed2004

Action-induced blindness with lateralized stimuli and responses.

Previous dual-task studies showed that the selection and/or execution of a response interfere with concurrent visual encoding (action-induced blindness). Four experiments examined how the lateralization of stimuli and responses might affect action-induced blindness. Participants responded to tones (S1) by pressing keys with the left or right hand (R1), and simultaneously identified stimuli (S2) presented to the left or right visual field. Results revealed a complex pattern of cross-talk effects between response preparation and visual encoding. Firstly, preparing a response generally impaired concurrent visual encoding. Secondly, action-induced blindness was equally present for ipsilaterally and contralaterally presented stimuli. Thirdly, response preparation facilitated processing of visual stimuli at ipsilateral locations, probably a case of action-centered attention. Finally, the facilitatory effect of R1-S2 correspondence on visual encoding was complemented by a S2-R1 correspondence effect on response execution. Thus, acting while seeing can have both beneficial and detrimental effects on identification performance at the same time.

Adolescent↗

PubMed2004

Sequential modulations of logical-recoding operations in the Simon task.

The Simon effect consists of faster responses to the color (or another nonspatial feature) of spatially corresponding stimuli than to spatially noncorresponding stimuli. Recently, several studies observed the Simon effect after corresponding predecessor trials, but not after noncorresponding predecessor trials. To explain these sequential modulations, Stürmer et al. (2002) proposed a mechanism modulating the ability of stimulus position to automatically activate a response. The present study investigated which events are effectively triggering this mechanism in a variant of the Simon task, in which both stimuli and responses varied in color (participants wore colored gloves) as well as in horizontal position. In the same-color task (e.g., green stimulus-green response), a normal Simon effect showed up after corresponding trials, but no effect occurred after noncorresponding trials. In the alternate-color task (e.g., green stimulus-red hand), no effect occurred after spatially corresponding trials, whereas an inverted Simon effect was found after noncorresponding trials. Additional analyses showed that repetition (or alternation) effects did not affect the results. The results are discussed in terms of a conflict-monitoring account (Stürmer et al., 2002), and in terms of a feature-integration account (Hommel et al., 2002).

Adult↗

PubMed2003

Actions blind to conceptually overlapping stimuli.

Participants are worse at identifying spatial symbols (arrowheads) while performing spatially compatible manual key presses. The present experiments investigated the generality of this "blindness effect" to response-compatible stimuli. In Experiment 1 a left key press deteriorated the identification of left-pointing arrows, and a right key press deteriorated the perception of right-pointing arrows, independent of the hands used to press the key. Thus the blindness effect is based on codes of the distal response location rather than on the body-intrinsic anatomical connection of the hands. Experiment 2 extended the blindness effect to verbal responses and written position words (left, right, up, down). Vocalizing a position word blinded to directly compatible position words (e.g., left-left), but not to orthogonally compatible position words (e.g., left-down). This result suggests that the use of identical stimulus-response codes, and not the use of saliency-matching but distinct codes, suffices to produce blindness effects. Finally, Experiment 3 extended the blindness phenomenon beyond the spatial domain by demonstrating blindness between saying color words and perceiving color patches. Altogether, the experiments revealed action-induced blindness to be a phenomenon of broad empirical validity occurring whenever action and perception afford simultaneous access to the same conceptual codes.

Adolescent↗

PubMed2003

Object-based attentional selection can modulate the Stroop effect.

The Stroop (1935) effect is the inability to ignore a color word when the task is to report the ink color of that word (i.e., to say "green" to the word RED in green ink). The present study investigated whether object-based processing contributes to the Stroop effect. According to this view, observers are unable to ignore irrelevant features of an attended object (Kahneman & Henik, 1981). In three experiments, participants had to name the color of one of two superimposed rectangles and to ignore words that appeared in the relevant object, in the irrelevant object, or in the background. The words were congruent, neutral, or incongruent with respect to the correct color response. Words in the irrelevant object and in the background produced significant Stroop effects, consistent with earlier findings. Importantly, however, words in the relevant object produced larger Stroop effects than did the other conditions, suggesting amplified processing of all the features of an attended object. Thus, object-based processing can modulate the Stroop effect.

Adult↗