Mila Sugovic

Performance and Ease Influence Perceived Speed

According to the action-specific perception account, perception is a function of optical information and the perceivers ability to perform the intended action. While most of the evidence for the action-specific perception account is on spatial perception, in the current experiments we examined similar effects in the perception of speed. Tennis players reproduced the time the ball traveled from the feeder machine to when they hit it. The players judged the ball to be moving faster on trials when they hit the ball out-of-bounds than on trials where they successfully hit the ball in-bounds. Follow-up experiments in the laboratory showed that participants judged virtual balls to be moving slower when they played with a bigger paddle in a modified version of Pong. These studies suggest that performance and task ease influence perceived speed.

When Walls are No Longer Barriers: Perception of Wall Height in Parkour:

Through training, skilled parkour athletes (traceurs) overcome everyday obstacles, such as walls, that are typically insurmountable. Traceurs and untrained novices estimated the height of walls and reported their anticipated ability to climb the wall. The traceurs perceived the walls as shorter than did novices. This result suggests that perception is scaled by the perceivers anticipated ability to act, and is consistent with the action-specific account of perception.

An older view on distance perception: older adults perceive walkable extents as farther

According to the action-specific perception account, spatial perception is affected by the specific energetic costs required to perform an action. In the current experiments, we examined the effect of age on distance perception. Older and younger adults were asked to verbally estimate distance to a target placed in a hallway. Results showed that older adults estimated distances to be farther compared to younger adults. Additionally, older and younger adults estimated distances on a surface that was easier to walk on (carpet) and on a surface that was more difficult to walk on (carpet covered by a plastic tarp). For older adults, distances looked farther on the plastic surface than on the carpet. These differences across surfaces were not found for able, younger adults. These results suggest that the type of floor surface available influences perception of distances. Furthermore, the results suggest that perception is still sensitive to environmental differences that affect ability even as a perceiver ages.

Action-Specific Effects in a Social Context: Others' Abilities Influence Perceived Speed.

According to the action-specific account of perception, perceivers see the environment relative to their ability to perform the intended action. For example, in a modified version of the computer game Pong, balls that were easier to block looked to be moving slower than balls that were more difficult to block (Witt & Sugovic, 2010). It is unknown, however, if perception can be influenced by another persons abilities. In the current experiment, we examined whether another persons ability to block a ball influenced the observers perception of ball speed. Participants played and observed others play the modified version of Pong where the task was to successfully block the ball with paddles that varied in size, and both the actor and observer estimated the speed of the ball. The results showed that both judged the ball to be moving faster when it was harder to block. However, the same effect of difficulty on speed estimates was not found when observers watched a computer play, suggesting the effect is specific to people and not to the task. These studies suggest that the environment can be perceived relative to another persons abilities.

Response Bias Cannot Explain Action-Specific Effects: Evidence from Compliant and Non-Compliant Participants

According to the action-specific account of perception, the perceivers ability to act influences perception of the target. For example, targets that are easier to acquire are reported to look closer, bigger, and slower. However, an alternative explanation for these effects is that they are due to response bias, rather than to changes in perception. To test the role of response bias, we employed two separate manipulations. We manipulated peoples abilities to block a ball and measured the corresponding effects on estimated ball speed. We also created an explicit task demand by giving participants instructions that emphasized responding either slow or fast. Participants were grouped, based on whether they were compliant or non-compliant with the instructions. Regardless of their compliance, we found an action-specific effect of blocking ability on estimated speed. Given that non-compliant participants still showed the effect, the results provide strong evidence against a response-bias explanation of this action-specific effect. Paired with earlier research, we conclude that blocking ability influences perceived speed. Perception expresses the relationship between the environment and the perceiver, and this view is consistent with emerging neural and behavioral evidence for an interconnected perceptual–motor system.

Spiders appear to move faster than non-threatening objects regardless of one's ability to block them.

We examined whether perception of a threatening object - a spider - was more accurate than of a non-threatening object. An accurate perception could promote better survival than a biased perception. However, if biases encourage faster responses and more appropriate behaviors, then under the right circumstances, perceptual biases could promote better survival. We found that spiders appeared to be moving faster than balls and ladybugs. Furthermore, the perceivers ability to act on the object also influenced perceived speed: the object looked faster when it was more difficult to block. Both effects--the threat of the object and the perceivers blocking abilities--acted independently from each other. The results suggest effects of multiple types of affordances on perception of speed.

Perceived distance and obesity: It's what you weigh, not what you think.

Action abilities are constrained by physical body size and characteristics, which, according to the action-specific account of perception, should influence perceived space. We examined whether physical body size or beliefs about body size affect distance perception by taking advantage of naturally-occurring dissociations typical in people who are obese but believe themselves to weigh less. Normal weight, overweight, and obese individuals made verbal distance estimates. We also collected measures of beliefs about body size and measures of physical body size. Individuals who weighed more than others estimated distances to be farther. Furthermore, physical body weight influenced perceived distance but beliefs about body size did not. The results illustrate that whereas perception is influenced by physical characteristics, it is not influenced by beliefs. The results also have implications for perception as a contributing factor for lifestyle choices: people who weigh more than others may choose to perform less physically demanding actions not as a result of how they perceive their bodies, but as a result of how they perceive the environment.

Catching ease influences perceived speed: evidence for action-specific effects from action-based measures.

According to the action-specific account of perception, people perceive the environment in terms of their ability to act. Here, we directly tested this claim by using an action-based measure of perceived speed: Participants attempted to catch a virtual fish by releasing a virtual net. The net varied in size, making the task easier or harder. We measured perceived speed by using explicit judgment-based measures and an action-based measure (time to release the net). Participants released the net later when playing with the big as compared with the small net, indicating that the fish looked to be moving more slowly when participants played with the big net. Explicit judgments of fish speed were similarly influenced by net size. These results provide converging evidence from both explicit and action-based measures that a perceiver’s ability to act influences a common underlying process, most likely perceived speed, rather than postperceptual processes such as response formation.

A perceiver's own abilities influence perception, even when observing others.

Perceptual judgments of objects, such as judgments of their size, distance, and speed, are influenced by the perceiver’s ability to act on these objects. For example, objects that are easier to block appear to be moving slower than objects that are more difficult to block. These effects are known as action-specific effects. Recent research has found similar patterns when a person observes someone else act: When the other person’s task is more difficult, objects look farther away and faster to the observer, whereas when the other person’s task is easier, the objects look closer and slower to the observer. These previous findings that another person’s ability penetrates into perceptual judgments challenge the idea that action-specific effects are specific to the perceiver’s own abilities. However, in the present study, we show that the apparent effects of another person’s ability on the observer’s judgments are actually due to the observer’s own abilities as if he or she was in the other person’s situation. This implicates a type of self-projection motor simulation mechanism. The results also preserve the critical idea that action-specific effects are perceiver specific and, consequently, that they could be adaptive for planning future actions.

An action-specific effect on perception that avoids all pitfalls

The visual system is influenced by action. Objects that are easier to reach or catch look closer and slower, respectively. Here, we describe evidence for one action-specific effect, and show that none of the six pitfalls can account for the results. Vision is not an isolate module, as shown by this top-down effect of action on perception.