The role of attention for the Simon effect

Abstract

It has been claimed that spatial attention plays a decisive role in the effect of irrelevant spatial stimulus-response correspondence (i.e., the Simon effect), especially the way the attentional focus is moved onto the stimulus (lateral shifting rather than zooming). This attentional-movement hypothesis is contrasted with a referential-coding hypothesis, according to which spatial stimulus coding depends on the availability of frames or objects of reference rather than on certain attentional movements. In six experiments, reference objects were made available to aid spatial coding, which either appeared simultaneously with the stimulus (Experiments 1-3), or were continuously visible (Experiments 4-6). In contrast to previous experiments and to the attentional predictions, the Simon effect occurred even though the stimuli were precued by large frames surrounding both possible stimulus positions (Experiment 1), even when the reference object's salience was markedly reduced (Experiment 2), or when the precueing frames were made more informative (Experiment 3). Furthermore, it was found that the Simon effect is not reduced by spatial correspondence between an uninformative spatial precue and the stimulus (Experiment 4), and it does not depend on the location of spatial precues appearing to the left or right of both possible stimulus locations (Experiment 5). This was true even when the precue was made task-relevant in order to ensure attentional focusing (Experiment 6). In sum, it is shown that the Simon effect does not depend on the kind of attentional operation presumably performed to focus onto the stimulus. It is argued that the available data are consistent with a coding approach to the Simon effect which, however, needs to be developed to be more precise as to the conditions for spatial stimulus coding.

Time course analyses confirm independence of imitative and spatial compatibility.

“…By manipulating response time with respect to the irrelevant movement stimulus, it was possible to investigate the build-up and/or decay of the spatial compatibility and imitative compatibility effects over time within a trial. Hommel (1993;1994), in a spatial compatibility task, presented the discriminative stimulus 196 ms after the irrelevant spatial stimulus. This manipulation delayed the response time with respect to the processing of the irrelevant spatial stimulus, which resulted in a reduced spatial compatibility effect.…”

“…Hommel's (1993;1994) data suggested that a delay of 196 ms between the onset of the irrelevant movement stimulus and the discriminative stimulus was sufficient for the decay of the spatial compatibility effect. In order to investigate the intermediate stages of this decay, levels of offset giving delays of 80 ms and 160 ms were chosen whereby the discriminative stimulus was presented after the irrelevant movement stimulus.…”

How the speed of motor-response decisions, but not focal-attentional selection, differs as a function of task set and target prevalence

“…In localization tasks, a target item typically is present on each trial, and participants are required to indicate a spatial characteristic of the target (e.g., whether the target is positioned to the left or to the right of the vertical midline of the display). In such tasks, the S-R mapping can be spatially congruent (e.g., left-hand response for the left target position) or incongruent (e.g., left-hand response for right target position), with the latter inducing substantial RT costs (the Simon effect) (6,7). Note that in detection and localization tasks, it is sufficient to know either whether or where a target appeared in the display.…”

Colour in action: evidence for a redundancy signal effect when driving motor responses by combined colour and spatial cues

“…The conditional presumed ventral task (perceptual route, De Jong, Liang, & Lauber, 1994;Hommel, 1993;Kornblum, Hasbroucq, & Osman, 1990) was a motor response to a particular colour cue; for example: "press the left button on a response box if you see the fixation cross turns red". An unconditional, presumed dorsal task (action route, De Jong et al, 1994;Hommel, 1993;Kornblum et al, 1990) was a response which spatially corresponded to the stimulus location (spatial cues); for example: "press the left response box button if the fixation cross jumps to the left".…”

“…An unconditional, presumed dorsal task (action route, De Jong et al, 1994;Hommel, 1993;Kornblum et al, 1990) was a response which spatially corresponded to the stimulus location (spatial cues); for example: "press the left response box button if the fixation cross jumps to the left". The interference between colour and spatial cues was measured using a redundant-target paradigm (Miller, 1982(Miller, , 1986Mordkoff & Yantis, 1993).…”