  Usage of smartphones and tablets have been increasing rapidly with
multi-touch interaction and powerful configurations. Performing tasks on mobile
phones become more complex as people age, thereby increasing their cognitive
workload. In this context, we conducted an eye tracking study with 50
participants between the age of 20 to 60 years and above, living in Bangalore,
India. This paper focuses on visual nature of interaction with mobile user
interfaces. The study aims to investigate how aging affects user experience on
mobile phones while performing complex tasks, and estimate cognitive workload
using eye tracking metrics. The study consisted of five tasks that were
performed on an android mobile phone under naturalistic scenarios using eye
tracking glasses. We recorded ocular parameters like fixation rate, saccadic
rate, average fixation duration, maximum fixation duration and standard
deviation of pupil dilation for left and right eyes respectively for each
participant. Results from our study show that aging has a bigger effect on
performance of using mobile phones irrespective of any complex task given to
them. We noted that, participants aged between 50 to 60+ years had difficulties
in completing tasks and showed increased cognitive workload. They took longer
fixation duration to complete tasks which involved copy-paste operations.
Further, we identifed design implications and provided design recommendations
for designers and manufacturers.
