Abstract
Previous researchers have explored the effects of visual occlusion on egocentric distance perception and blind-walking down straight pathways. For example, Rieser et al. (1990) reported no systematic error in blind-walking distance of up to 22 m following an 8 sec occlusion time (OT). Tyrrell et al. (1993) reported a gradual decay in the distance blind-walked down a straight pathway as OTs increased. More recently, Tyrrell et al. (1997) and Brown et al. (2004) found that even after longer OTs, blind-walking participants did know where straight ahead was, but still suffered from decay in path-walking performance. To further explore the characteristics of blind-walking, the present study tested 25 college-aged participants using a 40 cm wide by 15 sm long pathway laid out on a gymnasium floor. Their instructions were to blind-walk down the pathway following 5, 30, or 60 sec OTs. On some trials, a target cone was placed in the path's center at 4 or 12 m, and instructions were to stop when they believed they had reached the cone. Distance walked within the path was measured on every trial; total distance walked and stopping location's lateral position from the path's center (veering) was measured on target-present trials. Similar to previous studies, there was an OT effect as participants walked shorter distances following longer OTs. Interestingly, when targets were present, path distances walked tended to be shorter at all OTs. There was more veering on 12 m target trials, and longer OTs tended to increase veer. On average, participants walked about 85% of target distances. Although inconclusive, preliminary results tended to show that longer OTs increase distances walked to shorter targets and reduce distances walked to further targets. In conclusion, longer OTs do seem to affect blind-walking, veering and distance perception differently from shorter ones.