How Old Do I Look? Exploring the Facial Cues of Age in a Tasked Eye-Tracking Study

Importance: This is the first eye-tracking study to use a tasked age estimation paradigm to explore the facial cues of age as seen by casual observers. Objectives: Determine where observers gaze on faces when tasked with estimating an individual's age. Design, Setting, and Participants: This was a prospective controlled experiment, which took place at an academic tertiary referral center. In total, 220 casual observers (80 untasked, 140 tasked) viewed frontal facial images of women while an infrared eye-tracking monitor recorded their eye movements and fixations in real time. Main Outcomes and Measures: Multivariate Hotelling's analysis followed by planned posthypothesis testing was used to compare fixation durations for predefined regions of interest, including the central triangle, upper face, midface, lower face, and neck between tasked and untasked observers. Results: A total of 80 observers (mean age 23.6 years, 53% female) successfully completed the first untasked eye-tracking experiment. A total of 140 observers (mean age 26.1 years, 60% female) successfully completed the second age estimation experiment. On multivariate analysis, there were significant differences in the distribution of attention between observers in the two experiments (T-2 = 99.70; F(5,2084) = 19.9012, p < 0.0001). On planned posthypothesis testing, observers attended significantly more to the lower third of the face (0.20 s, p < 0.0001, 95% confidence interval (CI) 0.14-0.27 s) and neck (0.05 s, p = 0.0074, 95% CI 0.01-0.08 s) and less to the upper third of the face (-0.27 s, p < 0.0001, 95% CI -0.40 to -0.14 s) when tasked. There was no significant difference in time spent on the whole face in the two experiments, suggesting that peripheral elements such as hair color or jewelry did not significantly influence gaze patterns. Conclusions and Relevance: Humans form judgments about others every day of their lives, and age perception colors their every interaction. To our knowledge, this study is the first to use eye tracking to investigate facial cues of age. The results showed that when tasked with estimating age, casual observer visual attention was shifted toward the lower face when compared with those who were untasked. These data inform our understanding of facial age perception and potential areas to target for facial rejuvenation.