Nadine Chahine

Assessing the impact of typeface design in a text-rich automotive user interface

Text-rich driver–vehicle interfaces are increasingly common in new vehicles, yet the effects of different typeface characteristics on task performance in this brief off-road based glance context remains sparsely examined. Subjects completed menu selection tasks while in a driving simulator. Menu text was set either in a ‘humanist’ or ‘square grotesque’ typeface. Among men, use of the humanist typeface resulted in a 10.6% reduction in total glance time as compared to the square grotesque typeface. Total response time and number of glances showed similar reductions. The impact of typeface was either more modest or not apparent for women. Error rates for both males and females were 3.1% lower for the humanist typeface. This research suggests that optimised typefaces may mitigate some interface demands. Future work will need to assess whether other typeface characteristics can be optimised to further reduce demand, improve legibility, increase usability and help meet new governmental distraction guidelines. Practitioner Summary: Text-rich in-vehicle interfaces are increasingly common, but the effects of typeface on task performance remain sparsely studied. We show that among male drivers, menu selection tasks are completed with 10.6% less visual glance time when text is displayed in a ‘humanist’ typeface, as compared to a ‘square grotesque’.

Utilising psychophysical techniques to investigate the effects of age, typeface design, size and display polarity on glance legibility.

Abstract Psychophysical research on text legibility has historically investigated factors such as size, colour and contrast, but there has been relatively little direct empirical evaluation of typographic design itself, particularly in the emerging context of glance reading. In the present study, participants performed a lexical decision task controlled by an adaptive staircase method. Two typefaces, a ‘humanist’ and ‘square grotesque’ style, were tested. Study I examined positive and negative polarities, while Study II examined two text sizes. Stimulus duration thresholds were sensitive to differences between typefaces, polarities and sizes. Typeface also interacted significantly with age, particularly for conditions with higher legibility thresholds. These results are consistent with previous research assessing the impact of the same typefaces on interface demand in a simulated driving environment. This simplified methodology of assessing legibility differences can be adapted to investigate a wide array of questions relevant to typographic and interface designs. Practitioner Summary: A method is described for rapidly investigating relative legibility of different typographical features. Results indicate that during glance-like reading induced by the psychophysical technique and under the lighting conditions considered, humanist-style type is significantly more legible than a square grotesque style, and that black-on-white text is significantly more legible than white-on-black.

A Pilot Study Measuring the Relative Legibility of Five Simplified Chinese Typefaces Using Psychophysical Methods

In-vehicle user interfaces increasingly rely on screens filled with digital text to display information to the driver. As these interfaces have the potential to increase the demands placed upon the driver, it is important to design them in a way that minimizes attention time to the device and thus keeps the driver focused on the road. Previous research has shown that even relatively subtle differences in the design of the on-screen typeface can influence to-device glance time in a measurable and meaningful way. Here we outline a methodology for rapidly and flexibly investigating the legibility of typefaces in glance-like contexts, and apply this method to a comparison of 5 Simplified Chinese typefaces. We find that the legibility of the typefaces, measured as the minimum presentation time needed to read character strings and respond to a yes/no lexical decision task, is sensitive to differences in the typefaces design characteristics. The most legible typeface under study could be read 33.1% faster than the least legible typeface in this glance-induced context. Benefits and limitations of the methodology are discussed.

Empirical Assessment of the Legibility of the Highway Gothic and Clearview Signage Fonts

Older drivers represent the fastest-growing segment of the driving population. Aging is associated with well-known declines in reaction time and visual processing, and, as such, future roadway infrastructure and related design considerations will need to accommodate this population. One potential area of concern is the legibility of highway signage. FHWA recently revoked an interim approval that allowed optional use of the Clearview typeface in place of the traditional Highway Gothic typeface for signage. The legibility of the two fonts was assessed with color combinations that maximized the contrast (positive or negative) or approximated a color configuration used in highway signage. Psychophysical techniques were used to establish thresholds for the time needed to decide accurately—under glancelike reading conditions—whether a string of letters was a word, as a proxy for legibility. These thresholds were lower for Clearview (indicating superior legibility) than for Highway Gothic across all conditions. Legibility thresholds were lowest for negative-contrast conditions and highest for positive-contrast conditions, with colored highway signs roughly between the two extremes. These thresholds also increased significantly across the age range studied. The method used to investigate the legibility of signage fonts adds methodological diversity to the literature along with evidence supporting the superior legibility of the Clearview font over Highway Gothic. The results do not suggest that the Clearview typeface is the optimal solution for all signage but they do indicate that additional scientific evaluations of signage legibility are warranted in different operating contexts.

The Effect of Font Weight and Rendering System on Glance-Based Text Legibility

In-vehicle user interfaces increasingly rely on digital text to display information to the driver. Led by Apples iOS, thin, lightweight typography has become increasingly popular in cutting-edge HMI designs. The legibility trade-offs of lightweight typography are sparsely studied, particularly in the glance-like reading scenarios necessitated by driving. Previous research has shown that even relatively subtle differences in the design of the on-screen typeface can influence to-device glance time in a measurable and meaningful way. Here we investigate the relative legibility of four different weights (line thicknesses) of type under two different rendering systems (suboptimal rendering and optimal rendering). Results indicate that under suboptimal rendering, the lightest weight typeface renders poorly and is associated with markedly degraded legibility. Under optimal rendering, lighter weight typefaces show enhanced legibility compared to heavier typefaces. The reasons for this pattern of results, and its implications for design considerations in modern HMIs, are discussed.

These Labels are Nuts: Challenges to Safe Product Identification for Nut-Allergic Consumers

Allergen information on food labels is not standardized, making allergen avoidance difficult for consumers. This study investigated the speed and accuracy of allergen identification on commercial packaging across different types of warning labels. The results identified packaging label characteristics significantly correlated with faster and more accurate identification of allergens. Standardizing warning and safe-to-consume labels may reduce risk of accidental allergen exposure for consumers managing food allergies.

The effects of visual crowding, text size, and positional uncertainty on text legibility at a glance

Reading at a glance, once a relatively infrequent mode of reading, is becoming common. Mobile interaction paradigms increasingly dominate the way in which users obtain information about the world, which often requires reading at a glance, whether from a smartphone, wearable device, or in-vehicle interface. Recent research in these areas has shown that a number of factors can affect text legibility when words are briefly presented in isolation. Here we expand upon this work by examining how legibility is affected by more crowded presentations. Word arrays were combined with a lexical decision task, in which the size of the text elements and the inter-line spacing (leading) between individual items were manipulated to gauge their relative impacts on text legibility. In addition, a single-word presentation condition that randomized the location of presentation was compared with previous work that held position constant. Results show that larger text was more legible than smaller text. Wider leading significantly enhanced legibility as well, but contrary to expectations, wider leading did not fully counteract decrements in legibility at smaller text sizes. Single-word stimuli presented with random positioning were more difficult to read than stationary counterparts from earlier studies. Finally, crowded displays required much greater processing time compared to single-word displays. These results have implications for modern interface design, which often present interactions in the form of scrollable and/or selectable lists. The present findings are of practical interest to the wide community of graphic designers and interface engineers responsible for developing our interfaces of daily use.

The Cost of Cool: Typographic Style Legibility in Reading at a Glance

When designers typographically tweak fonts to make an interface look ‘cool,’ they do so amid a rich design tradition, albeit one that is little-studied in regards to the rapid ‘at a glance’ reading afforded by many modern electronic displays. Such glanceable reading is routinely performed during human-machine interactions where accessing text competes with attention to crucial operational environments. There, adverse events of significant consequence can materialize in milliseconds. As such, the present study set out to test the lower threshold of time needed to read and process text modified with three common typographic manipulations: letter height, width, and case. Results showed significant penalties for the smaller size. Lowercase and condensed width text also decreased performance, especially when presented at a smaller size. These results have important implications for the types of design decisions commonly faced by interface professionals, and underscore the importance of typographic research into the human performance impact of seemingly “aesthetic” design decisions. The cost of “cool” design may be quite steep in high-risk contexts.