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Vasudevan Lakshminarayanan, Aparna Raghuram; Aging and Estimation of time to collision. Journal of Vision 2004;4(8):755. doi: 10.1167/4.8.755.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Does perceived time to collision (ttc) estimates vary as a function of age? Methods: Data was collected from young subjects (20–30 years; n=10) and older subjects (65–81 years; n=4). Subjects viewed a square target moving horizontally towards an end point marked by a vertical line on a monitor. Stimulus motion was visible up to 50% of the overall distance to be covered and then disappeared from the screen. Subjects had to estimate the perceived ttc and press a button on the response box to record their percept. The difference between the actual and the perceived ttc was calculated. Data was collected for three different reference speeds and three different distances. Results: Both older and younger subjects underestimate the perceived ttc. The magnitude of underestimation was significantly higher for older subjects compared to younger subjects at p=0.000. The error in perception on the ttc task decreases as speed increases and as distance increases, except for the longest distance with the fastest reference speed tested. The trend was similar for both age groups. Central viewing condition resulted in better performance compared to peripheral viewing (p=0.000). No significant difference was observed for central viewing condition on the perceived ttc when the overall luminance was decreased from mesopic to scotopic levels. Conclusion: Error in perception on a ttc task varies as a function of age. This has implications for studies on driving performance.
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