Does empirical evidence from healthy aging studies predict a practical difference between visualizations for different age groups?

TL;DR

This paper reviews evidence from aging studies and proposes a model to predict how visual perception differences across age groups affect visualization effectiveness, emphasizing contrast and spatial frequency considerations.

Contribution

It introduces a new model linking age-related contrast sensitivity decline to visualization design guidelines based on psychophysical data.

Findings

Older adults have reduced contrast sensitivity at higher spatial frequencies.

Visualizations with contrast of 0.02 or higher are perceivable by all age groups.

Designing visualizations to avoid high spatial frequencies improves accessibility for older viewers.

Abstract

When communicating critical information to decision-makers, one of the major challenges in visualization is whether the communication is affected by different perceptual or cognitive abilities, one major influencing factor is age. We review both visualization and psychophysics literature to understand where quantitative evidence exists on age differences in visual perception. Using contrast sensitivity data from the literature we show how the differences between visualizations for different age groups can be predicted using a new model of visible frequency range with age. The model assumed that at threshold values some visual data will not be visible to older people (spatial frequency > 2 and contrast <=0.01). We apply this result to a practical visualization and show an example that at higher levels of contrast, the visual signal should be perceivable by all viewers over 20. Universally usable visualization should use a contrast of 0.02 or higher and be designed to avoid spatial frequencies greater than eight cycles per degree to accommodate all ages. There remains much research to do on to translate psychophysics results to practical quantitative guidelines for visualization producers.