Affective states leak into movement execution: Automatic avoidance of threatening stimuli in fear of spider is visible in reach trajectories

Abstract

Approach-like actions are initiated faster with stimuli of positive valence. Conversely, avoidance-like actions are initiated faster with threatening stimuli of negative valence. We went beyond reaction time measures and investigated whether threatening stimuli also affect the way in which an action is carried out. Participants moved their hand either away from the picture of a spider (avoidance) or they moved their hand toward the picture of a spider (approach). We compared spider-fearful participants to non-anxious participants. When reaching away from the threatening spider picture, spider-fearful participants moved more directly to the target than controls. When reaching toward the threatening spider, spider-fearful participants moved less directly to the target than controls. Some conditions that showed clear differences in movement trajectories between spider-fearful and control participants were devoid of differences in reaction time. The deviation away from threatening stimuli provides evidence for the claim that affective states like fear leak into movement programming and produce deviations away from threatening stimuli in movement execution. Avoidance of threatening stimuli is rapidly integrated into ongoing motor behaviour in order to increase the distance between the participant's body and the threatening stimulus.

Keywords:

• Affective states
• Hand trajectories
• Reaching
• Spider phobia
• Threat

Acknowledgments

DK was supported by the Swiss National Foundation (SNF 10011-107768/1 and PDFM1-114417/1), MR by the Behavioural Science Institute, Nijmegen.

We are grateful to the reviewers for helpful comments on an earlier version of the article.