Redundant-target processing is robust against changes to task load

Stephanie A Morey,Jason S Mccarley,Nicole A Thomas

doi:10.1186/s41235-017-0088-x

Abstract

Monitoring visual displays while performing other tasks is commonplace in many operational environments. Although dividing attention between tasks can impair monitoring accuracy and response times, it is unclear whether it also reduces processing efficiency for visual targets. Thus, the current three experiments examined the effects of dual-tasking on target processing in the visual periphery. A total of 120 undergraduate students performed a redundant-target task either by itself (Experiment 1a) or in conjunction with a manual tracking task (Experiments 1b–3). Target processing efficiency was assessed using measures of workload resilience. Processing of redundant targets in Experiments 1–2 was less efficient than predicted by a standard parallel race model, giving evidence for limited-capacity, parallel processing. However, when stimulus characteristics forced participants to process targets in serial (Experiment 3), processing efficiency became super-capacity. Across the three experiments, dual-tasking had no effect on target processing efficiency. Results suggest that a central task slows target detection in the display periphery, but does not change the efficiency with which multiple concurrent targets are processed.

Highlights

Operators in high-stress domains often need to divide attention between the central and peripheral visual fields
Error rates Detection error rates were analyzed to ensure that participants had correctly followed instructions
Participants correctly responded to approximately 72 trials in each condition: M = 71.80 (Range = 67–75) for lefttargets, M = 71.68 (Range = 67–75) for right-targets, and M = 71.56 (Range = 66–74) for redundant targets

Summary

Introduction

Operators in high-stress domains often need to divide attention between the central and peripheral visual fields. An obvious technique to improve target detection is to increase target salience, the feature contrast between the target and its surroundings (Itti & Koch, 2000; Theeuwes, 2010). Alternative strategies for ensuring rapid target detection are, useful. One converging strategy is to present targets redundantly, that is, on multiple channels simultaneously. Redundant presentation generally speeds target detection (Miller, 1982; Todd, 1912), and is endorsed in human factors engineering as a method of promoting information security (Wickens & Hollands, 2000; Wickens, Prinet, Hutchins, Sarter, & Sebok, 2011). In aircraft settings, pilots respond faster to missile approach warnings as the number of informational channels delivering the warning increases (Selcon, Taylor, & McKenna, 1995)

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