Stopping in (e)motion: Reactive action inhibition when facing valence-independent emotional stimuli

Abstract

Emotions are able to impact our ability to control our behaviors. However, it is not clear whether emotions play a detrimental or an advantageous effect on action control and whether the valence of the emotional stimuli differently affects such motor abilities. One way to measure reactive inhibitory control is the stop-signal task (SST), which estimates the ability to cancel outright a response to the presentation of a stop signal by means of the stop signal reaction times (SSRT). Impaired as well as facilitated action control has been found when faced with emotional stimuli such as stop signals in SSTs and mixed results were observed for positive versus negative stimuli. Here, we aimed to investigate these unresolved issues more deeply. Action control capabilities were tested in 60 participants by means of a SST, in which the stop signals were represented by a fearful and a happy body posture together with their neutral counterpart. Results showed that both positive and negative body postures enhanced the ability to suppress an ongoing action compared to neutral body postures. These results demonstrate that emotional valence-independent emotional stimuli facilitate action control and suggest that emotional stimuli may trigger increased sensory representation and/or attentional processing that may have promote stop-signal processing and hence improved inhibitory performance.

Keywords: action inhibition; emotional body expression; emotions; stop-signal task (SST); valence-arousal.

FIGURE 1

Visual stimuli used as Stop-Signal stimuli. In the Fear-Body group, stimuli consisted of two different body pictures with fearful and neutral body expression, and in the Joy-Body group stimuli were represented by happy and neutral body postures, previously used and validated in Borgomaneri et al., 2012, ,,, , , .

FIGURE 2

Sequence of trials in the stop-signal task (SST). The experimental task includes both go- and stop-trials (Lappin and Eriksen, 1966; Logan and Cowan, 1984b; Logan et al., 2014; Verbruggen et al., 2019). Participants perform a short practice block and, immediately afterward, four experimental blocks. Each block includes a total of 128 trials, of which 96 are go-trials (75%) and 32 are stop-trials (25%). In go-trials, participants respond to the go-task (i.e., the direction of the arrow that appears on the screen) by pressing the corresponding arrow key on the keyboard. In stop-trials, the arrow is followed by a “Stop” signal after a variable stop-signal delay (FIX, fixation duration; SSD, stop signal delay; ITI, intertrial interval), instructing participants to suppress the imminent go response. The initial value of the SSD was set to 150 ms and adjusted individually and dynamically throughout the experiment (i.e., staircase procedure).

FIGURE 3

Bar graphs of the experimental results. In panel (A), the graph shows the mean stop-signal delay (SSD), demonstrating that the emotional content of stimuli influenced the participant’s action execution leading to a specific differentiation of SSD, given the successful staircase procedure. In panel (B), the graph shows the mean stop-signal reaction time (SSRT), demonstrating that participants showed a better inhibitory process when facing emotive Stop-signals as compared to neutral ones, regardless of the group. *Indicate significant comparisons (p < 0.05), and error bars represent S.E.M.