May the force be against you: Better visual sensitivity to speed changes opposite to gravity.

Abstract

Beyond seemingly lower-level features such as color and motion, visual perception also recovers properties more commonly associated with higher-level thought, as when an upwardly accelerating object is seen not just as moving, but moreover as self-propelled, and resisting the force of gravity. Given past research demonstrating the prioritization of living things in attention and memory, here we hypothesized that observers would be more sensitive to an object’s speed changes if those speed changes were opposite to natural gravitational acceleration. Across six experiments, we found that observers were more sensitive to objects’ accelerations when they moved upward (when those accelerations were opposite to gravity) and less sensitive to their accelerations when they moved downward (when those accelerations were consistent with gravity). Moreover, observers were more sensitive to objects’ decelerations when they moved downward (when those decelerations appeared as “braking” against gravity), and less sensitive to their decelerations when they moved upward (when those decelerations were consistent with gravity). This greater visual sensitivity to speed changes opposite to gravity is consistent with previous results suggesting that we readily monitor the world for cues to animacy.

A visual bias for falling objects

“…As mentioned in the introduction, a recent study by Nguyen and van Buren (2023) found greater sensitivity to Up compared to Down, which would predict higher values of the slope parameter b in our study. Our ANOVAs however revealed no significant differences in slopes either between Up and Down or between Left and Right, although, in keeping with Nguyen & van Buren, there is a visibly higher average slope for Up compared to Down with the 1.5 s transit time (see Figure 3c ).…”

“…The studies most relevant to the present one are those by Calderone and Kaiser (1989) and Nguyen and van Buren (2023) . They measured sensitivity to acceleration as a function of motion direction, with Calderone and Kaiser (1989) finding no difference between Up and Down and Nguyen and van Buren (2023) finding higher sensitivity for Up than Down. None of the above studies however considers whether subjects are biased in their perception of whether something is accelerating or decelerating depending on the direction of motion or whether any such dependency would be perceptual or cognitive in origin (but see Freyd & Finke, 1984 ; Hubbard, 2020 ).…”

“…Perceptual bias is not the same as perceptual sensitivity . Previous studies have measured how sensitive we are to acceleration, specifically how much an object needs to accelerate to be discriminable from one that is moving at a constant speed ( Calderone & Kaiser, 1989 ; Lee et al, 2019 ; Mueller & Timney, 2016 ; Nakayama & Motoyoshi, 2017 ; Nguyen & van Buren, 2023 ; Schmerler, 1976 ; Watamaniuk & Heinen, 2003 ; Werkhoven et al, 1992 ). The studies most relevant to the present one are those by Calderone and Kaiser (1989) and Nguyen and van Buren (2023) .…”

“…Previous studies have measured how sensitive we are to acceleration, specifically how much an object needs to accelerate to be discriminable from one that is moving at a constant speed ( Calderone & Kaiser, 1989 ; Lee et al, 2019 ; Mueller & Timney, 2016 ; Nakayama & Motoyoshi, 2017 ; Nguyen & van Buren, 2023 ; Schmerler, 1976 ; Watamaniuk & Heinen, 2003 ; Werkhoven et al, 1992 ). The studies most relevant to the present one are those by Calderone and Kaiser (1989) and Nguyen and van Buren (2023) . They measured sensitivity to acceleration as a function of motion direction, with Calderone and Kaiser (1989) finding no difference between Up and Down and Nguyen and van Buren (2023) finding higher sensitivity for Up than Down.…”

Perceiving animacy from kinematics: visual specification of life-likeness in simple geometric patterns

“…Consistently, it has been shown that observers are much more sensitive to speed changes in the direction opposite to the direction of gravity when they are required to report whether or not a speed change has occurred (Nguyen and van Buren, 2023).…”