Date of Award


Degree Name

MS in Industrial Engineering


Industrial and Manufacturing Engineering


Reza Pouraghabagher


Touch screen technology is rapidly increasing, and at the same time there is a shifting, aging population. As the percentage of the population over the age of 65 increases, adults of the age group are adopting smartphones and tablets more now than ever before. Although older adults are adopting touch screen devices, they face many challenges when interacting with said devices, such as not knowing how to navigate between pages, not knowing where to click for an action to occur, and the touch screen interface is often too sensitive or the buttons are not big enough. Furthermore, the challenges of aging, specifically sensory and cognitive decline resulting from aging affect comprehension and spacial processing, which are critical when navigating through an interface.

The purpose of this thesis was to better understand redundancy effect applied to females and males between the ages of 65 and 84. There were two tasks of different lengths, and for each task there were two designs. The first design included text only buttons, and the second included symbol + text buttons, the latter being the redundant interface. Quantitative results yielded no significant results for time for either task. Qualitative results included ratings for ease of navigation, general satisfaction, overall understanding, and button design preference. Preferences between text only buttons were statistically significant; for the task of online grocery shopping and booking a cruise, females prefer text only buttons and males prefer symbol + text buttons (p = 0.0068 and p = 0.0024). Although button design had no significance in completing a task, significant preference results indicate likelihood to return to a given website. Furthermore, although quantitative results were not significant, gender did influence average times per task and average ratings across categories. Further research could be conducted with larger sample sizes, other forms of redundancy, and larger tasks, however it is evident through this experiment that gender has an impact on how adults between 65 and 84 perceive and navigate through touch screen interfaces given the constraints of the symbols used, ages, and task designs. Therefore, concluding recommendations based on the qualitative data suggest that designers should create gender specific interfaces based on gender favored websites, or design based on the ability to customize the interface upon entering a website.

Included in

Ergonomics Commons