Visual–motor recalibration in geographical slant perception.

Abstract

In 4 experiments, it was shown that hills appear steeper to people who are encumbered by wearing a heavy backpack (Experiment 1), are fatigued (Experiment 2), are of low physical fitness (Experiment 3), or are elderly and/or in declining health (Experiment 4). Visually guided actions are unaffected by these manipulations of physiological potential. Although dissociable, the awareness and action systems were also shown to be interconnected. Recalibration of the transformation relating awareness and actions was found to occur over long-term changes in physiological potential (fitness level, age, and health) but not with transitory changes (fatigue and load). Findings are discussed in terms of a time-dependent coordination between the separate systems that control explicit visual awareness and visually guided action.In conscious awareness, the apparent slant of hills is greatly exaggerated. For example, 5° hills appear to be about 20°, and 10° ones look to be about 30° (Proffitt, Bhalla, Gossweiler, & Midgett, 1995). Be that as it may, people are not especially prone to stumble whenever the terrain over which they walk changes in slant. When ascending a 5° hill, people appropriately raise their feet to accommodate this incline, not a 20° one.In this and our previous article (Proffitt et al., 1995), we suggest that the exaggeration of slant in conscious awareness promotes the function of relating distal inclines to one's physiological potential. Given gravity and one's physiology, a long 5° hill is actually rather difficult to ascend, and consequently it appears to be quite steep. Given this proposal, we predict that geographical slant will change with changes in physiological potential.The first purpose of this article is to provide support for this prediction. In four experiments, we show that hills appear steeper when people are (a) encumbered by wearing a heavy backpack, (b) fatigued after a long run, (c) of low physical fitness, and (d) elderly or in poor health. None of

Interacting with objects compresses environmental representations in spatial memory

“…Recently, it has been argued that certain demonstrations of action-specific perception (e.g., Bhalla & Proffitt, 1999) do not reflect perceptual distortions, but rather the participants' ability to ascertain the experimenters' hypotheses and to alter their responses accordingly (see, e.g., Durgin et al, 2009). Could demand characteristics explain the results that we obtained in Experiment 1?…”

Physical and mental effort disrupts the implicit sense of agency

“…For instance, perceived distance increases and hills seem steeper under conditions requiring more physical exertion (e.g. when carrying a heavy load; Bhalla & Proffitt, 1999;Sugovic & Witt, 2013;Witt, Proffitt, & Epstein, 2004). These apparent spatial distortions as a function of required effort are also mirrored for the perception of time.…”

Use of slope and feature cues in pigeon (Columba livia) goal-searching behavior.

“…There is growing evidence in support of how embodied constraints scale perception and how effort seems to play a key role in this ( Gibson, 1979;Witt, Proffitt, & Epstein, 2010). For example, effort required for walking influences distance estimation ( Proffitt, Stefanucci, Banton, & Epstein, 2003;Rieser, Pick, Ashmead, & Garing, 1995), and the physiological potential of an observer (including level of fatigue) affects the judgments of hill slant ( Bhalla & Proffitt, 1999; but see Shaffer & Flint, 2011). It has also been shown that effort required to solve a foraging task alters the pattern of search behavior ( Gilchrist, North, & Hood, 2001).…”