Table 3. Summary of obstacle detection, collision and false reports.

The percentage of obstacle-present trials is reported in which the obstacle was detected, or for which collisions did not occur. The percentage of false reports of the obstacle being present for obstacle-absent trials is also reported. Performance under auditory guidance, SSD guidance, and for the “no-click” control experiment is reported. Under visual guidance, the obstacle was always detected, no collisions occurred, and there were no false reports.

	Normally sighted (mean, SD)	Blind non-echolocators (mean, SD)	BE (mean)
% of trials in which the obstacle was detected
Auditory guidance	75 (18)	96 (4)	100
SSD	100 (0)	100 (0)	100
“no-click” control experiment	21 (31)	81 (21)	83
% of trials where collision did not occur
Auditory guidance	58 (21)	88 (7)	94
SSD	93 (8)	90 (15)	83
“no-click” control experiment	11 (23)	69 (19)	50
% of false reports of obstacle being present
Auditory guidance	17 (22)	27 (23)	0
SSD	0 (0)	0 (0)	0
“no-click” control experiment	0 (0)	25 (46)	0