Why does the effect of short-SOA exogenous cuing on simple RT depend on the number of display locations?

When the stimulus onset asynchrony (SOA) between the cue and target is short (i.e., less than 200 msec) and the number of display locations is small (e.g., only two), exogenous spatial cues produce a benefit in simple response time (RT). However, several recent experiments have found significant costs in these tasks when a large number of display locations is employed (e.g., eight), even at the very short SOAs that usually produce a benefit. The present study explored the dependence of exogenous cuing on the number of display locations and found evidence that both the overall validity of the cues and the specific validity of the cue on the previous trial have strong, additive effects. When a large number of display locations is used, both of these factorswork against a benefit of exogenous cuing on simple RT, reversing the typical finding into a cost. These two effects are suggested to occur within motor and perceptual processes, respectively.     

On the spatial metric of short-SOA costs of exogenous cuing

When the stimulus onset asynchrony (SOA) between the cue and the target is short, exogenous spatial cues usually produce a response time benefit. However, consistent with several recent studies, we have found that a short stimulus onset asynchrony is not sufficient. At least one more factor--the number of cue and target locations--also plays a role. Even more interesting, when 8 cue and target locations are used, the effect of an exogenous cue produces a cost on valid cue trials, and the spatial metric of this negative cuing effect depends on whether the cue remains visible at target onset.     

Parallel patterns of spatial compatibility and spatial congruence…as long as you don't look too closely

The effects of spatial compatibility and spatial congruence have both been explained in terms of a dual-route model under which spatial information about the stimulus, regardless of task relevance, is directly passed from perception to action. Recently, however, some alternatives to the dual-route model of the Simon Effect have been proposed (or re-introduced) as viable explanations. The present experiment compared the magnitudes of the effects of spatial compatibility and spatial congruence across a range of tasks that varied in their dimensional overlap. The results exhibited a remarkable parallel between the two phenomena when viewed only in terms of the interaction between stimulus set and response set. This could be taken as new evidence for a common origin. However, when the entire pattern of results was examined, a large difference between compatibility and congruence were also seen, which implies that there is at least one important difference between the two phenomena.     

Looking for the source of the simon effect: evidence of multiple codes

The Simon effect (SE) usually is described as the performance advantage that results when a target and its associated response share the same spatial code, as opposed to when they do not, even when the target's spatial code is task-irrelevant. To some, this task-irrelevant code represents the location of the target with respect to the participant (Simon & Craft, 1970), whereas to others (Umiltà & Nicoletti, 1992) it represents the location of the target with respect to the locus of attention. By using a spatial cuing procedure, we simultaneously tested both of these hypotheses and found evidence that both types of codes produce independent SEs, therefore providing evidence that multiple spatial codes can simultaneously influence performance in a Simon task.     

An apparent-motion confound causes the negative exogenous cuing effect at SOAs with larger numbers of target locations

Salient but irrelevant stimuli seem to cause an automatic orienting of covert attention, facilitating the detection of targets at the cued location for a brief period of time. However, this finding is highly dependent on the number of possible target locations, at least when the simple detection of targets is all that the task requires. Whereas small numbers of possible target locations (e.g., 2 or 3) produce the well-known advantage in response time for valid cue trials (i.e., a positive cuing effect), larger numbers of possible target locations (e.g., 6 or 8) produce a negative cuing effect. If not explained in terms of a nonattentional mechanism, this latter finding raises serious questions about the standard interpretation of positive cuing effects. The present experiment tested a particular nonattentional mechanism: that a confound between target presence and apparent motion, which occurs only on invalid cue trials, is responsible for negative cuing effect. We reduced or eliminated this confound by the use of a new type of catch trial and eliminated the negative cuing effect with large numbers of target locations.     

Contingent Capture at a very short SOA: Evidence against Rapid Disengagement

Salient cues that do not contain the target's defining attribute do not cause a spatial cueing effect in response time when presented 150 ms before the target. This can be explained by Contingent Capture (under which incongruent cues do not capture attention) and also by Rapid Disengagement (under which salient but incongruent cues cause only brief capture). To discriminate between these models, a very short SOA of 35ms was employed in the standard paradigm. As is true for longer SOAs, there was no evidence of attentional capture by salient but incongruent cues. Thus, the evidence to date favours Contingent Capture over Rapid Disengagement.     

Correction to: Effects of average uncertainty and trial-type frequency on choice response time: A hierarchical extension of Hick/Hyman law

Psychonomic Bulletin & Review - In Mordkoff (2017), the intention was to exclude from the analyses all trials that immediately followed an error.     

Observation: Three reasons to avoid having half of the trials be congruent in a four-alternative forced-choice experiment on sequential modulation

Sequential modulation is the finding that the sizes of several selective-attention phenomena--namely, the Simon, flanker, and Stroop effects--are larger following congruent trials than following incongruent trials. In order to rule out relatively uninteresting explanations of sequential modulation that are based on a variety of stimulus- and response-repetition confounds, a four-alternative forced choice task must be used, such that all trials with any kind of repetition can be omitted from the analysis. When a four-alternative task is used, the question arises as to whether to have the proportions of congruent and incongruent trials be set by chance (and, therefore, be 25% congruent and 75% incongruent) or to raise the proportion of congruent trials to 50%, so that it matches the proportion of incongruent trials. In this observation, it is argued that raising the proportion of congruent trials to 50% should not be done. For theoretical, practical, and empirical reasons, having half of the trials be congruent in a four-alternative task aimed at providing unambiguous evidence of sequential modulation should be avoided.     

An interactive race model of divided attention.

Two classes of models have been proposed to explain how redundant information extracted from separate sources comes to activate a single response. Each provides a fundamentally different account of why responses to redundant signals are typically faster than those to either signal alone (the redundant-signals effect). Independent race models assume that a race occurs between perceptual codes on independent channels and that only the winner activates the response. Coactivation models assume that there is some form of energy or activation-strength summation, with information being pooled across channels prior to decision. An intermediate class of models is introduced and a specific exemplar, the interactive race model, is tested in a series of redundant-target detection experiments. In particular, we examine the effects on performance of two types of contingency that have previously been overlooked as sources of task-relevant information. The results reveal that response times are significantly influenced by both interstimulus and stimulus-response contingencies. The interactive race model provides a natural account of these findings as well as several otherwise puzzling results in the divided-attention literature.     

Feature integration without visual attention: Evidence from the correlated flankers task

It is widely assumed that the separable features of visual objects, such as their colors and shapes, require attention to be integrated. However, the evidence in favor of this claim comes from experiments in which the colors and shapes of objects would have to be integrated and then also subjected to an arbitrary, instruction-based, stimulus-response (S-R) translation in order to have an observable effect. This raises the possibility that attention is not required for feature integration, per se, but is only required when color-shape conjunctions must undergo an arbitrary S-R translation. The present study conducted a more specific test and found strong evidence in favor of feature integration in the absence of attention. The implications of these results are discussed.