Biomedical subjects

Jason Ivanoff

Publications and source records attributed to Jason Ivanoff.

6 recordsLinked to original sources

PubMed2004

Stimulus-response probability and inhibition of return.

Inhibition of return (IOR) refers to slowed responding to targets at a location previously occupied by an irrelevant cue. Here we explore the interaction between stimulus-response (S-R) probability and IOR effects using go/no-go (Experiment 1) and two-choice discrimination tasks (Experiment 2). In both experiments, the IOR effect was larger for the likely S-R ensemble than for the unlikely one. In the first experiment, there were more false alarms for uncued targets than for cued targets, and this difference was larger for the unlikely S-R ensemble than for the likely one. In the second experiment, the same pattern was observed for incorrect keypress responses. As with voluntary orienting in response to predictive central cues, the results suggest that IOR affects late stages of processing by altering the criteria to respond to targets presented at the cued (previously attended) location.

Conditioning, Classical↗

PubMed2003

On spatial response code activation in a Simon task.

The Simon effect refers to the performance advantage for trials where the task-irrelevant location of a target spatially corresponds with the location of the response. It is thought that the irrelevant spatial code of the target facilitates responding by automatically pre-activating the spatially corresponding response code. This spatial code is thought to passively decay shortly after its activation. In this investigation, the response was selected according to the identity of a central cue. The selected response was executed or withheld depending the identity (Experiment 1) or the presence (Experiment 2) of the target. Varying the stimulus-onset asynchrony (SOA), between the central response cue and the peripheral target, allowed for a time-course analysis of the Simon effect. The results of two experiments provided no indication that the activation level of the irrelevant spatial code decayed while the relevant response was prepared. Although reaction times increased as the SOA decreased, the Simon effect was additive with SOA, suggesting that the automatic activation of the task-irrelevant spatial code was delayed until the task-relevant response code was mostly prepared, perhaps due to the capacity limitations of response selection.

Humans↗

PubMed2003

The interplay of stop signal inhibition and inhibition of return.

Inhibition of return (IOR) refers to slower responding to a stimulus that appears in the same rather than a different location as that of a preceding stimulus. The goal of the present study was to examine the relationship between IOR and stop signal inhibition. Participants were presented with two stimuli (S1 and S2) on each trial. On half of the trials (go trials), participants were required to make a speeded button-press response to report the location of S1; on the other half of trials (stop trials), they were required to cancel the response to S1, as indicated by the appearance of a stop signal at a variable delay (stop signal delay, SSD) after the appearance of S1. Success in cancelling an S1 response varied directly as a function of the SSD: The longer the delay, the more difficult it was for participants to cancel the prepared response. We examined the magnitude of IOR in the S2 reaction times as a function of whether participants made a correct go response to S1, made an erroneous non-cancelled response to S1, or successfully cancelled a response to S1. Our results indicated that the presentation of a stop signal increased the magnitude of IOR, even when the S1 response was not successfully cancelled. However, this was true only when the to-be-cancelled response involved the same effectors as the response used to reveal IOR. These results suggest that there may be a motor component to IOR that is sensitive to the same inhibitory processes that are used to cancel responses in a stop signal paradigm.

Adult↗

PubMed2003

Orienting of attention without awareness is affected by measurement-induced attentional control settings.

McCormick (1997) concluded that peripheral cues presented below a threshold of awareness could nevertheless attract attention because they facilitated target processing near the cue shortly after its presentation. Yet, whereas an exogenous shift of attention typically exhibits a biphasic pattern (initial facilitation followed by inhibition of return [IOR]), at late cue-target onset asynchronies, IOR was not observed by McCormick. In our study, targets requiring a detection response were preceded by masked and nonmasked, uninformative cues presented under two conditions: one in which the cue was ignored (no report) and one in which the cue was detected and localized following the response to the target (cue report). When participants were required to make cue judgments at the end of each trial, we replicated McCormick's pattern, finding facilitation (but not IOR) following both masked and nonmasked cues. When there was no requirement to judge the presence or location of the cues, IOR was present with and without masks, whereas facilitation was observed only when the cues were not masked. That the assessment of cue awareness increases attentional facilitation and prevents (or delays) the onset of IOR is attributed to attentional control settings put in place to perform the cue-awareness assessments in the cue-report condition.

Attention↗

PubMed2002

Inhibition of return interacts with the Simon effect: an omnibus analysis and its implications.

Previous research has reported that the Simon effect (a type of stimulus-response [S-R] compatibility effect) and the inhibition of return effect (IOR; a late cuing effect) do not interact. In this brief report, we analyzed published and unpublished experiments that have examined these effects and found that IOR actually increases the Simon effect. This is a remarkable finding because most factors that delay reaction times (as IOR does) actually decrease the Simon effect. We examine this interaction within the context of seven interpretations of the effect that IOR may have on the task-irrelevant S-R code and two interpretations of the effect that IOR may have on the task-relevant S-R code, two components that underlie the Simon effect. The results falsified more than half of these interpretations, thus permitting future investigations to further reduce the number of theoretical alternatives.

Attention↗

PubMed1999

Performance Asymmetries in Computer Mouse Control of Right-Handers, and Left-Handers with Left- and Right-Handed Mouse Experience.

Precision and general computer mouse aiming performance by right-handers (RH-RM) and left-handers with right-handed mouse experience (LH-RM) and by left-handers with left-handed mouse experience (LH-LM) were compared. A number of performance measures, such as reaction time, time to reach a target, time to click on target, and cursor trajectory, were analyzed. Superficially, specific hand experience seemed to dictate performance asymmetries, but a closer look revealed interactions between hand preference and hand performance. That finding has implications for theories of handedness. In addition, precision and general directional aiming with the mouse cursor showed a clear right hand superiority in reaction time in both RH-RM and LH-RM subjects, whereas LH-LM subjects showed no lateral asymmetries. Finally, the overall time taken for the task, averaged across groups and conditions, favored the experienced hand by some 180 ms. In practical terms, that is not a large difference, especially because the difference will be reduced with practice. Thus, the use of the inexperienced hand can be advocated when there is a need to forestall or ameliorate repetitive stress in the experienced hand.

Journal Article↗