Abstract
People tend to underestimate the time required to walk to a previewed target in imagined walking tasks (Kunz et al., 2007, 2008; Yamamoto & Philbeck, 2008). One explanation is that the initial target distance was visually underperceived. Other explanations are possible, however. Here, we tested two alternative hypotheses. First, people may overestimate walking speed in imagined walking. Second, imagined walking may be subject to errors of anticipation (the general tendency to terminate a response prematurely). To test these ideas, an experimenter marked out various time intervals (1–8 s), during which time blindfolded participants were to physically walk or to imagine walking. At the end of the specified interval, participants verbally estimated the distance they walked or imagined walking. In the real walking condition, participants were guided along a linear path at a fixed rate of 1 m/s. The experimenter determined the stopping point. In the imagined walking condition (conducted after the real walking condition), the experimenter specified the time interval by saying “start” and “stop”; during the specified interval, participants were required to imagine walking in the same manner as in the real walking condition. According to the first hypothesis, if there is a tendency to overestimate walking speed during imagined walking relative to real walking, estimated walked distances would be longer in the imagined walking condition. The second hypothesis predicts that similar distance estimates would be made in both conditions because participants had no prior knowledge about where they would be walking (and therefore errors of anticipation were removed). Results showed that there was no significant difference in distance estimates between real and imagined walking, indicating that the participants did not overestimate their walking speed in imagined walking. This finding suggests that the underestimation of imagined walking time is explained in part by errors of anticipation.
Supported by NIH 5R01NS052137-04