title: Goal-directed action is automatically biased towards looming motion.
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.
authors.affiliation: Cognitive, Linguistic, & Psychological Sciences, Brown University, United States. Electronic address: jeff_moher@brown.edu.
authors.forename: Jeff
authors.initials: J
authors.lastname: Moher
authors.affiliation: Cognitive, Linguistic, & Psychological Sciences, Brown University, United States.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sit
authors.affiliation: Cognitive, Linguistic, & Psychological Sciences, Brown University, United States; Brown Institute for Brain Sciences, Brown University, United States.
authors.forename: Joo-Hyun
authors.initials: JH
authors.lastname: Song
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011601:Psychophysics; D055815:Young Adult
keywords: Looming motion; Movement trajectories; Selection bias; Visually-guided action