Witt, J. K., Proffitt, D. R., & Epstein, W. (2004). Perceiving distance: A role of effort and intent. Perception, 33(5), 577-590.

Perceiving egocentric distance is not only a function of the optical variables to which it relates, but also a function of people’s current physiological potential to perform intended actions. In a set of experiments, we showed that, as the effort associated with walking increases, perceived distance increases if the perceiver intends to walk the extent, …