This is the latest in a series of studies showing that our perceptions are grounded firmly in our actions. Witt’s group has previously demonstrated that perceptions of goal size in golfers and softball players are apparently affected by performance. Other researchers have shown that perception is also influenced by the amount of effort required to perform an action. A location seems further away when one has to walk uphill to reach it, or if one is tired or in pain during the walk, and hills look steeper when one is carrying a heavy backpack. Similarly, objects that are just out of reach are perceived to be closer when one is holding atool that extends reach, while those that are positioned so that they are difficult to grasp are perceived as beign further away.
All of these studies show that perception does not merely involve reconstructing the geometry of one’s environment from visual information. Rather, our perceptions seem to be firmly grounded in, and strongly influenced by, the abilities, intentions and efforts of the perceiver. This may be because we view the environment in terms of energy costs, and plan our actions accordingly. Thus, a tired walker who perceives a hill to be steeper than it actually is will walk more slowly, and an athelete who perceives a target to be bigger will need to expend less energy and attention. Conserving energy is vital for survival, so such an adaptation would confer an important evolutionary advantage.