Figure 1.

Distance reproduction task. Subjects were initially presented at a random location within a field environment with a random placement of objects. In the production phase, subjects were required to walk toward the red sphere on the horizon. After a predetermined distance (d _p), unknown to the subject, subjects were stopped and told to reproduce the distance they had just walked. In the reproduction phase, subjects walked until they believed they had matched d _p, marking the reproduced distance (d _r) with a button press. Subjects were not aware of the range of distances presented, and did not receive feedback on their performance. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]