. Author manuscript; available in PMC: 2011 May 1.

Published in final edited form as: Accid Anal Prev. 2010 May;42(3):818–826. doi: 10.1016/j.aap.2009.04.023

Table 1.

Means and Standard Deviations of Participants' Demographic Information and Results from Perceptual and Cognitive Tests

Variable	Younger		Older

	M	SD	M	SD
Age (years)^a	21.1	2.67	72.6	4.62
Years of education^a	14.0	1.3	16.8	2.1
Snellen Letter Acuity	10/10.8	1.7	10/13	2.3
Log Contrast Sensitivity^a,^b	1.75	0.06	1.62	0.19
Digit Span Forward	11.0	1.7	12.1	2.0
Digit Span Backward	7.6	2.9	8.0	2.1
Perceptual Encoding Manual^a	92.2	13.3	67.0	12.5
Kaufman Brief Intelligence Test	28.3	4.4	29.9	4.8

Differences between age groups were significant (p ≤ .05) for both sets of age groups.

Contrast sensitivity was measured using the Pelli Robson test (Pelli, Robson, & Wilkins, 1988).