Motion disrupts dynamic visual search for an orientation change

Emily M Crowe,Christina J Howard,Iain D Gilchrist,Christopher Kent

doi:10.1186/s41235-021-00312-2

Abstract

Visual search in dynamic environments, for example lifeguarding or CCTV monitoring, has several fundamentally different properties to standard visual search tasks. The visual environment is constantly moving, a range of items could become targets and the task is to search for a certain event. We developed a novel task in which participants were required to search static and moving displays for an orientation change thus capturing components of visual search, multiple object tracking and change detection paradigms. In Experiment 1, we found that the addition of moving distractors slowed participants’ response time to detect an orientation changes in a moving target, showing that the motion of distractors disrupts the rapid detection of orientation changes in a moving target. In Experiment 2 we found that, in displays of both moving and static objects, response time was slower if a moving object underwent a change than if a static object did, thus demonstrating that motion of the target itself also disrupts the detection of an orientation change. Our results could have implications for training in real-world occupations where the task is to search a dynamic environment for a critical event. Moreover, we add to the literature highlighting the need to develop lab-based tasks with high experimental control from any real-world tasks researchers may wish to investigate rather than extrapolating from static visual search tasks to more dynamic environments.

Highlights

Most papers in the visual search literature begin with the description of a daily task which requires us to locate a target object amongst other distracting objects
We checked for any evidence for a second ‘guessing’ peak which would suggest that a participant applied a time threshold strategy and just responded after a set period of time without detecting an orientation change
The data from two participants was removed because their data suggested they either produced too many anticipatory responses or were inattentive

Summary

Introduction

Most papers in the visual search literature begin with the description of a daily task which requires us to locate a target object amongst other distracting objects. In some dynamic visual search tasks, we must track the changing spatial locations of target and distractor items as they move around the environment. Lifeguards are required to search dynamic aquatic environments for the occurrence of dangerous events such as drowning; and CCTV operators must monitor a bank of screens to detect suspicious behaviour In these examples the environment observed constantly changes with high possibilities of occlusion and changing motion patterns: factors that are commonly studied using an MOT paradigm In other related work, Tripathy and Barrett (2004) developed a task which assessed participants’ ability to detect a deviation from the linear trajectory of moving items In their Experiments 3 and 4, all items were potential targets (i.e., could deviate from a linear trajectory) requiring participants to monitor the trajectories of all items simultaneously.

Results and discussion

Conclusions