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

Tool Use Affects Spatial Perception

Tools do not just expand our capabilities. They change what we can do, and in doing so, they change who we are. Serena is Serena because of what she can do with a tennis racket. Tiger is Tiger because of what he can do with a golf club. In changing what we can do, tools also change the very way we perceive the spatial layout of the world. Objects beyond arm's reach appear closer when we wield a tool that can expand out to the object. Catchable objects seem to move faster when we wield a tool that is less effective for catching the object. These examples illustrate how the basic processes of spatial vision are impacted by tool use.

Action's influence on spatial perception: resolution and a mystery

Despite the impression that perception of spatial layout including distance, slant, and size is objective and geometrically accurate, spatial perception is influenced by a perceiver's ability to act. Hills appear steeper when the perceiver is fatigued, and balls appear faster when they are harder to block. The same environment looks different when the perceiver is better able to act than when actions are constrained. Claims of action's influence on spatial perception have been met with much controversy, and spurred many experiments designed to explore alternative explanations. In at least one case, these alternative explanations have failed to account for action's effect, thereby leading to the conclusion that the potential for action can truly influence spatial perception. The mystery remains, however, as to how action exerts its influence.

In absence of an explicit judgment, action-specific effects still influence an action measure of perceived speed

Action-specific effects, such as a fish appearing faster when it is harder to catch, have been primarily demonstrated using explicit perceptual judgments. These sorts of judgments rely on the cognitive or "what" visual pathway. An open question is whether action-specific effects also influence the action pathway. If fish look faster when the net is small, the net should be released earlier than when the net is big. Previously, this action measure was always paired with an explicit measure of fish speed, which is known to evoke the cognitive visual pathway. Here, net release time was examined without any explicit judgments. The action-specific effect of net size still emerged. Assuming net release time taps into the action pathway, the current studies provide support that action-specific effects occur within both the cognitive and action pathways, possibly because these effects operate on early visual processes prior to the split between the two pathways.

Is There a Chastity Belt on Perception?

Can one's ability to perform an action, such as hitting a softball, influence one's perception? According to the action-specific account, perception of spatial layout is influenced by the perceiver's abilities to perform an intended action. Alternative accounts posit that purported effects are instead due to nonperceptual processes, such as response bias. Despite much confirmatory research on both sides of the debate, researchers who promote a response-bias account have never used the Pong task, which has yielded one of the most robust action-specific effects. Conversely, researchers who promote a perceptual account have rarely used the opposition's preferred test for response bias, namely, the postexperiment survey. The current experiments rectified this. We found that even for people naive to the experiment's hypothesis, the ability to block a moving ball affected the ball's perceived speed. Moreover, when participants were explicitly told the hypothesis and instructed to resist the influence of their ability to block the ball, their ability still affected their perception of the ball's speed.

What you see and what you are told: an action-specific effect that is unaffected by explicit feedback

A critical question for theories of spatial vision concerns the nature of the inputs to perception. The action-specific account asserts that information related to action, specifically a perceiver's ability to perform the intended action, is one of these sources of information. This claim challenges assumptions about the mind in general and perception in particular, and not surprisingly, has been met with much resistance. Alternative explanations include that these effects are due to response bias, rather than genuine differences in perception. Using a paradigm in which ease to block a ball impacts estimated speed of the ball, participants were given explicit feedback about their perceptual judgements to test the response bias alternative. Despite the feedback, the action-specific effect still persisted, thus ruling out a response-bias interpretation. Coupled with other research ruling out additional alternative explanations, the current findings offer an important step towards the claim that a person's ability to act truly influences spatial perception.

Action potential influences spatial perception: Evidence for genuine top-down effects on perception

The action-specific account of spatial perception asserts that a perceiver's ability to perform an action, such as hitting a softball or walking up a hill, impacts the visual perception of the target object. Although much evidence is consistent with this claim, the evidence has been challenged as to whether perception is truly impacted, as opposed to the responses themselves. These challenges have recently been organized as six pitfalls that provide a framework with which to evaluate the empirical evidence. Four case studies of action-specific effects are offered as evidence that meets the framework's high bar, and thus that demonstrates genuine perceptual effects. That action influences spatial perception is evidence that perceptual and action-related processes are intricately and bidirectionally linked.

Dissociating perception from judgment in the action-specific effect of blocking ease on perceived speed

The action-specific approach to perception claims that a person's ability to act directly influences perceptual processes related to spatial vision. For example, a person's ability to block a moving ball impacts perceptual judgments of the ball's speed. However, an alternative explanation is that action rather than perception influences judgments. Here, we explore this distinction directly. Our method produces two distinct effects, one that is clearly a judgment-based effect and is based on the outcome of the trial (trial-outcome effect) and one that is under debate as to whether or not it is perceptual and is based on the ease with which the ball can be blocked (paddle-size effect). We explored whether these two effects would produce convergence or dissociations across various populations and manipulations. A dissociation is evidence for two separate underlying processes, whereas if the two effects did not dissociate, this would be consistent with claims that both effects were judgment-based. In Experiment 1, we examined whether older and younger adults would show a dissociation between the two effects given some precedent for older adults to show greater susceptibility to nonperceptual factors in their judgments. In Experiment 2, we used a cover story to excuse poor performance and examined its effects on both types of effects. Both experiments revealed dissociations, suggesting that while one effect is judgment-based, the other effect is not. Coupled with prior research, we conclude that the action-specific effect of ease to block a ball on estimated ball speed is perceptual.

Discovering your inner Gibson: reconciling action-specific and ecological approaches to perception-action

Both the action-specific perception account and the ecological approach to perception-action emphasize the role of action in perception. However, the action-specific perception account demonstrates that different percepts are possible depending on the perceiver's ability to act, even when the same optical information is available. These findings challenge one of the fundamental claims of the ecological approach--that perception is direct--by suggesting that perception is mediated by internal processes. Here, we sought to resolve this apparent discrepancy. We contend that perception is based on the controlled detection of the information available in a global array that includes higher-order patterns defined across interoceptive and exteroceptive stimulus arrays. These higher-order patterns specify the environment in relation to the perceiver, so direct sensitivity to them would be consistent with the ecological claims that perception of the environment is direct and animal-specific. In addition, the action-specific approach provides further evidence for the theory of affordances, by demonstrating that even seemingly abstract properties of the environment, such as distance and size, are ultimately perceived in terms of an agent's action capabilities.

Awareness Is Not a Necessary Characteristic of a Perceptual Effect: Commentary on Firestone (2013)

Golf holes look larger to golfers who are playing better than others, and hills look steeper to people who are fatigued from a long run-or so claims the action-specific account of perception. According to this account, spatial perception of slant, distance, and size is influenced by the perceiver's ability to perform actions such as walking, throwing, or grasping. This claim is based on empirical findings that observers report hills as steeper, distances as farther, and objects as smaller when they are less capable of acting on the objects. Recently, Firestone (2013) challenged the claim that these reports reflect genuine differences in perception. One argument he levied against a perceptual interpretation is that people are not aware of these perceptual differences related to action, and they should be. Here, I argue that awareness is not a necessary condition for an effect to be perceptual, as evidenced by a lack of awareness in the case of a classic visual illusion. However, to make a strong claim for genuine effects in perception, the action-specific account must specify a perceptual mechanism, and it has yet to do so.

Action-specific perception of speed is independent of attention

According to the action-specific account of perception, a perceiver's ability to act influences how the environment is perceived. For example, in a computer-based task, participants perceive fish as moving faster when they use a smaller net, and are thus less effective at catching the fish (Witt & Sugovic, 2013a). Here, we examined the degree to which attention may influence perceptual judgments by requiring participants to engage in a secondary task that directed their attention either toward (Exp. 1) or away from (Exp. 2) the to-be-caught fish. Though perceived fish speed was influenced by participants' catching performance-replicating previous results-attentional allocation did not impact this relationship between catching performance and perceived fish speed. The present results suggest that action directly influences spatial perception, rather than exerting indirect effects via attentional processes.

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.

Action-specific influences on perception and postperceptual processes: Present controversies and future directions

The action-specific perception account holds that people perceive the environment in terms of their ability to act in it. In this view, for example, decreased ability to climb a hill because of fatigue makes the hill visually appear to be steeper. Though influential, this account has not been universally accepted, and in fact a heated controversy has emerged. The opposing view holds that action capability has little or no influence on perception. Heretofore, the debate has been quite polarized, with efforts largely being focused on supporting one view and dismantling the other. We argue here that polarized debate can impede scientific progress and that the search for similarities between 2 sides of a debate can sharpen the theoretical focus of both sides and illuminate important avenues for future research. In this article, we present a synthetic review of this debate, drawing from the literatures of both approaches, to clarify both the surprising similarities and the core differences between them. We critically evaluate existing evidence, discuss possible mechanisms of action-specific effects, and make recommendations for future research. A primary focus of future work will involve not only the development of methods that guard against action-specific postperceptual effects but also development of concrete, well-constrained underlying mechanisms. The criteria for what constitutes acceptable control of postperceptual effects and what constitutes an appropriately specific mechanism vary between approaches, and bridging this gap is a central challenge for future research.