Writing with the Eyes: The Effect of Age on Eye-Tracking Performance in Non-Disabled Adults and a Comparison with Bimanual Typing

Table 2

Typing speed and error rate across the 11 measurement sessions in the 3 age groups.

Variable	Age group		Session											Mean	95% confidence limit
			1	2	3	4	5	6	7	8	9	10	11
Typing speed	Young (N = 20)	Mean (char/s)	0.783	0.830	0.875	0.892	0.920	0.938	0.960	0.960	0.993	0.975	0.999	0.92	0.90–0.94
		SD	0.145	0.132	0.155	0.140	0.124	0.126	0.123	0.094	0.112	0.115	0.119
	Middle-aged (N = 23)	Mean (char/s)	0.608	0.676	0.708	0.738	0.771	0.798	0.822	0.821	0.829	0.839	0.867	0.77	0.75–0.79
		SD	0.098	0.122	0.105	0.108	0.108	0.096	0.116	0.110	0.114	0.108	0.113
	Elderly (N = 20)	Mean (char/s)	0.430	0.485	0.516	0.527	0.565	0.594	0.607	0.622	0.630	0.629	0.643	0.57	0.55–0.59
		SD	0.086	0.119	0.119	0.108	0.130	0.146	0.138	0.147	0.146	0.147	0.158
Error rate	Young (N = 20)	Mean (%)	4.706	3.529	2.941	2.059	1.176	1.765	0.294	1.471	0.588	1.176	1.471	1.93	1.46–2.39
		SD	4.516	4.003	4.476	3.454	3.077	2.766	1.315	3.757	1.811	3.077	3.236
	Middle-aged (N = 23)	Mean (%)	11.765	8.184	5.627	3.581	4.604	4.092	3.325	2.302	2.558	2.558	2.046	4.60	3.89–5.32
		SD	8.319	7.470	6.265	4.604	4.329	5.151	3.896	2.935	3.469	4.281	2.865
	Elderly (N = 20)	Mean (%)	17.647	16.471	15.294	11.471	8.824	7.353	6.176	4.412	4.412	4.118	4.412	9.14	8.05–10.24
		SD	8.746	9.466	7.489	9.247	6.748	7.361	3.002	4.214	4.626	4.714	3.757