Inhibition of return emerges with non-predictive spatial cueing of the stop-signal

Abstract

The ability to suppress an inappropriate response can be influenced by several factors, including providing information on where to pay attention. For example, the spatial prediction of the stop signal location enhances inhibitory control in a Stop Signal Task. Here, we test whether a non-predictive spatial cueing improves inhibitory control as well. In this experiment, participants observed a vertical bar moving from a central position toward one of two circles on the screen. They were asked to press a key when the bar's motion was interrupted (go signal). In 25% of the trials (stop signal trials), after a variable delay following the go signal, a visual target (stop signal) appeared in one of the circles, requiring participants to inhibit their response to the go signal. In half of these trials, the stop signal appeared on the same side as the go signal (valid condition), and in the other half, it appeared on the opposite side (invalid condition). Our results show a facilitation effect for stop trials in the invalid condition compared to the valid condition, for targets occurring from 300 ms onward the go signal. This suggests an involvement of Inhibition of Return (IOR) in affecting the stop signal detection during motor control. Our findings provide new insights into the interaction between attentional processes and motor control, highlighting a temporally focused influence of exogenous attention in shaping motor inhibition.

Keywords: attention; cognitive control; inhibition of return; motor inhibition; stop signal task.

Figure 1

Behavioral task. Trials begin with the presentation of a fixation screen consisting of two circles and a central gray rectangle with a black border on a white background. Subsequently, a black bar appears and starts moving toward one of the two circles in 150 ms steps. When the bar stops near one of the circles, that circle becomes a go signal, and the subject must respond. In stop trials, after a certain interval from the presentation of the go signal, a stop signal (i.e., the gray asterisk within the circle) appears. In this case, participants must attempt to inhibit their response. Stop trials can be classified as valid if the stop signal appears in the circle reached by the black bar, or invalid if it appears in the opposite circle. In the image, the stop signal has been enlarged to make it visible; for its actual size, see the Section 2.3.

Figure 2

Mean reaction times (in ms) and standard error (± 1 SEM) for the three experimental conditions. Three asterisks indicate a statistically significant difference at p < 0.001, as determined by a one-way repeated measures ANOVA conducted on RTs.

Figure 3

Inhibition function. Probability of response in relation to the stop condition (valid or invalid) and the Stop Signal Delay (100, 200, 300, 400 ms). One asterisk indicate a statistically significant difference at p < 0.05, as determined by a two-way repeated measures ANOVA conducted on probability of response.

Figure 4

Differences in probability of response (i.e., the probability of response in invalid trials minus that in valid trials of the specific Stop Signal Delay), also referred to as the validity effect, across every Stop Signal Delays (100, 200, 300, 400 ms). Positive values indicate that it was easier to inhibit in valid stop signal trials, whereas negative values indicate that inhibition was easier in invalid stop signal trials. Each small dot represents a single participant, while larger dots highlight clusters of participants with similar values. The vertical lines in each Stop Signal Delay plot represent the median for that specific delay.