An Eye Tracking Study on Vigilance Decrements in Closed Circuit Television Monitors

Abstract

Vigilance is the ability to sustain attention for a certain period of time. Vigilance decrements occur when a person is unable to maintain vigilance on a given task and performance suffers as a result. Vigilance decrements are common in long and monotonous tasks, such as Closed Circuit Television (CCTV) surveillance and can have detrimental consequences on the efficiency and safety of the system. There is thus a need to detect and inform users about these decrements. However, this requires analyzing eye tracking metrics over a shorter and earlier window of time than in previous studies. The overall goal of this study was to determine the attentional costs of vigilance decrements over a relatively short window of time. The application domain was CCTV surveillance. To this end, eighteen students from the American University of Beirut monitored a CCTV screen with four video feeds for suspicious events, such as taking the belongings of others. Performance measures were used to establish the presence of performance decrements. Eye tracking metrics were collected in two-minute intervals throughout the experiment as well as in two larger intervals. In general, the results revealed a trend of participants’ attention becoming faster and more spread out, as evidenced by shorter mean fixation duration and longer mean saccade length. The results can be used as the basis for further research on vigilance and eye tracking metrics over short windows of time, which can, in turn, help inform the design of adaptive displays that help prevent vigilance decrements.