Virtual arm's reach influences perceived distances but only after experience reaching.

Considerable empirical evidence has shown influences of the action capabilities of the body on the perception of sizes and distances. Generally, as one's action capabilities increase, the perception of the relevant distance (over which the action is to be performed) decreases and vice versa. As a consequence, it has been proposed that the body's action capabilities act as a perceptual ruler, which is used to measure perceived sizes and distances. In this set of studies, we investigated this hypothesis by assessing the influence of arm's reach on the perception of distance. By providing participant with a self-representing avatar seen in a first-person perspective in virtual reality, we were able to introduce novel and completely unfamiliar alterations in the virtual arm's reach to evaluate their impact on perceived distance. Using both action-based and visual matching measures, we found that virtual arm's reach influenced perceived distance in virtual environments. Due to the participants' inexperience with the reach alterations, we also were able to assess the amount of experience with the new arm's reach required to influence perceived distance. We found that minimal experience reaching with the virtual arm can influence perceived distance. However, some reaching experience is required. Merely having a long or short virtual arm, even one that is synchronized to one's movements, is not enough to influence distance perception if one has no experience reaching.