Elsevier

Vision Research

Volume 113, Part B, August 2015, Pages 188-197
Vision Research

Goal-directed action is automatically biased towards looming motion

https://doi.org/10.1016/j.visres.2014.08.005Get rights and content
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Highlights

  • Reaches are faster and more direct towards a target exhibiting looming motion.

  • Reaching movements are automatically attracted towards looming distractors.

  • Greater disruption from distractors looming on a collision path with the observer.

  • Reaching is a more sensitive tool to evaluate looming effects than psychophysics.

Abstract

It is known that looming motion can capture attention regardless of an observer’s intentions. Real-world behavior, however, frequently involves not just attentional selection, but selection for action. Thus, it is important to understand the impact of looming motion on goal-directed action to gain a broader perspective on how stimulus properties bias human behavior. We presented participants with a visually-guided reaching task in which they pointed to a target letter presented among non-target distractors. On some trials, one of the pre-masks at the location of the upcoming search objects grew rapidly in size, creating the appearance of a “looming” target or distractor. Even though looming motion did not predict the target location, the time required to reach to the target was shorter when the target loomed compared to when a distractor loomed. Furthermore, reach movement trajectories were pulled towards the location of a looming distractor when one was present, a pull that was greater still when the looming motion was on a collision path with the participant. We also contrast reaching data with data from a similarly designed visual search task requiring keypress responses. This comparison underscores the sensitivity of visually-guided reaching data, as some experimental manipulations, such as looming motion path, affected reach trajectories but not keypress measures. Together, the results demonstrate that looming motion biases visually-guided action regardless of an observer’s current behavioral goals, affecting not only the time required to reach to targets but also the path of the observer’s hand movement itself.

Keywords

Visually-guided action
Looming motion
Selection bias
Movement trajectories

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