Designing Touchscreen Menu Interfaces for In-Vehicle Infotainment Systems: the Effect of Depth and Breadth Trade-off and Task Types on Visual-Manual Distraction

TL;DR

This study investigates how menu depth, breadth, and task complexity affect visual-manual distraction in in-vehicle touchscreen interfaces, revealing that interaction effects influence driving safety and interface design considerations.

Contribution

It provides new insights into how secondary task types interact with menu structure to impact distraction, informing safer in-vehicle interface design.

Findings

Deeper menus increase visual demand during systematic reading tasks.

Optimal visual demand occurs at certain depths for search and memory tasks.

Design implications emphasize considering cognitive task types alongside menu layout.

Abstract

Multitasking with a touch screen user-interface while driving is known to impact negatively driving performance and safety. Literature shows that list scrolling interfaces generate more visual-manual distraction than structured menus and sequential navigation. Depth and breadth trade-offs for structured navigation have been studied. However, little is known on how secondary task characteristics interact with those trade-offs. In this study, we make the hypothesis that both menu's depth and task complexity interact in generating visual-manual distraction. Using a driving simulation setup, we collected telemetry and eye-tracking data to evaluate driving performance. Participants were multitasking with a mobile app, presenting a range of eight depth and breadth trade-offs under three types of secondary tasks, involving different cognitive operations (Systematic reading, Search for an item, Memorize items' state). The results confirm our hypothesis. Systematic interaction with menu items generated a visual demand that increased with menu's depth, while visual demand reach an optimum for Search and Memory tasks. We discuss implications for design: In a multitasking context, display design effectiveness must be assessed while considering menu's layout but also cognitive processes involved.