Abstract
Prior to performing a physical action in the environment, decisions must be made to select one from multiple potential actions and then from multiple ways of performing it. One of the chief factors involved in such decisions is the effort required to perform the action. Noting that effort can be difficult to measure, Rosenbaum, Brach, and Semenov (2010) implemented a two-alternative forced choice action procedure that required participants to choose between a short or long reach across a table to pick up a bucket, with the constraint that the choice would also determine how far they had to carry the bucket. Participants' action choices demonstrated a consistent trade-off between the costs of walking and reaching, indicating that the effort involved in individual components of an action sequence play a combined, predictable role in the choice of how to act. In the current study, we replicated their design with several additions. Of primary interest, participants' perception of one potential carrying distance was assessed on each trial prior to performing the actions. When the distance being estimated was one that they believed to require less combined reaching/walking effort (as indicated by the fact that they would later choose to carry the bucket over that distance instead of the alternative choice), the distance was perceived as shorter, and conversely when the distance being estimated was the one they believed to require more combined effort (i.e. they would later choose to carry the bucket over the alternate distance), the distance being estimated appeared farther. Thus, perception of a single component in an action sequence (distance to be walked) was influenced by a second component as well: the effort required to reach. In this respect, it may be that changes to conscious perception of spatial layout serve in part to guide complex action choices.