Manipulation of expended effort and intent does not affect estimates of slant or distance.

Abstract

It is well known that people overestimate the orientation of both geographical and man-made sloped surfaces by between 5°-20°. More recently, work has shown that when people are encumbered by wearing a heavy backpack they overestimate hills and distances even more than a group not wearing heavy backpacks; however, the backpack manipulation has since been shown to be a demand effect-that is, being encumbered does not affect perception-it only biases those people influenced by it to give estimates the experimenters are seeking. Here we first show that expended effort and intent have never actually been manipulated between subjects in any of the work on steepness estimates, and expended effort has never been explicitly manipulated between subjects for distance estimates. When they are, they do not affect steepness or distance estimates. Our work is the first to experimentally manipulate effort and intent, to do this between subjects, while controlling for demand characteristics and checking to see whether the effort manipulation was effective. The experimental manipulation of effort and especially intent may be of benefit to parsing out perceptual effects from more cognitive or postperceptual processes in future work. Public Significance StatementThis study investigated whether our perception of slant and distance are infiltrated by top-down influences or encapsulated from them. We directly manipulated effort (being pushed or pushing themselves) and intent (whether they thought they would go up the hill or not) using a wheelchair. We found no differences in steepness or distance estimates between effort or intent conditions. This work is the first to manipulate effort and intent directly between subjects, while controlling for experimental demand, and shows perception of steepness and distance are stable in the face of various physical and cognitive states of the observer.

Does who I am and what I feel determine what I see (or say)? A meta-analytic systematic review exploring the influence of real and perceived bodily state on spatial perception of the external environment

“… Taylor, Witt & Sugovic (2011) found that traceurs/parkour athletes ( i.e ., higher fitness/sport-specific training) estimated vertical wall height as significantly lower than untrained controls for a 1.94 m wall but not for higher walls (2.29 m, 3.45 m). Effect sizes were unable to be calculated for two other studies, but one found a non-significant relationship between waist-to-hip ratio and distance perception ( Cole, Balcetis & Zhang, 2013 ), and one found no relationship between self-rated fitness and a distance on hill measure ( Shaffer, Greer & Schaffer, 2019 ).…”

“…All experiments had high risk of bias ( Table 2 ). No experiments used random sampling and only 4% ( n = 3/68) performed a priori sample size calculations ( Scandola et al, 2019 ; Shaffer, Greer & Schaffer, 2019 ). Four experiments ( Dean et al, 2016 ; Durgin et al, 2012 ; Shaffer et al, 2013 ; Taylor-Covill & Eves, 2013 ) had low risk of bias for the spatial perception measure ( i.e ., reliability established by previous research).…”