Visual information about moving objects.

Todd, James T.

doi:10.1037/0096-1523.7.4.795

Cited by 280 publications

(268 citation statements)

References 47 publications

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“…In all such studies, however, information has been conceived in its traditional interpretation of the amount of uncertainty (Shannon & Weaver, 1949) rather than in terms of a lawful specification of events (Gibson, 1979) and invoked, moreover, an arbitrary coupling between stimulus and response. Having to increase or reverse the speed of movement on the basis of some light coming on at some unpredictable moment during movement execution, as in the Quinn and Sherwood (1983) study, can hardly be compared with, let alone generalized to, movement execution on the basis of a continuous information flow specifying present and future events (Bootsma, 1989;Fitch & Turvey, 1978;Kugler, Turvey, Carello, & Shaw, 1985;Lee, Young, Reddish, Lough, & Clayton, 1983;Runeson & Frykholm, 1983;Todd, 1981;Turvey & CareUo, 1986;Warren, Young, & Lee, 1986). Experiments in which subjects operate under real-life conditions can be logically expected to render a more thorough insight into the way behavior is coordinated with events in the environment.…”

Section: Continuous Guidancementioning

confidence: 99%

Timing an attacking forehand drive in table tennis.

Bootsma¹,

Wieringen²

1990

Journal of Experimental Psychology: Human Perception and Perfor

410

334

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Comparison of initial and terminal temporal accuracy of 5 male top table tennis players performing attacking forehand drives led to the conclusion that because of a higher temporal accuracy at the moment of ball/bat contact than at initiation the players did not fully rely on a consistent movement production strategy. Functional trial-to-trial variation was evidenced by negative correlations between the perceptually specified time-to-contact at the moment of initiation and the mean acceleration during the drive; within-trial adaptation was also evident for two of the Ss. It is argued that task constraints provide the organizing principles for perception and action at the same time, thereby establishing a mutual dependency between the two. Allowing for changes in these parameters over time, a unified explanation is suggested that does not take recourse to large amounts of (tacit) knowledge on the part of the S.

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Section: Continuous Guidancementioning

confidence: 99%

Timing an attacking forehand drive in table tennis.

Bootsma¹,

Wieringen²

1990

Journal of Experimental Psychology: Human Perception and Perfor

410

334

View full text Add to dashboard Cite

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“…Using the same type of analysis as Todd (1981), an optical variable specifying future passing distance can be derived (cf. Bootsma, 1991;Bootsma & Peper, 1992).…”

Section: Optical Specification Of Passing Distancementioning

confidence: 99%

“…The dot notation is used to indicate the time derivatives: Velocity is denoted by a single dot, acceleration by two dots. Because optical variables associated with one surface can be uniquely transformed into optical variables associated with any other surface (Lee, 1974;Todd, 1981), the present analysis is performed in reference to a planar surface parallel to the approaching object at unit distance from the point of observation, for reasons of mathematical convenience (Figure 1).…”

Section: Optical Specification Of Passing Distancementioning

confidence: 99%

“…However, it is important to realize that direction of motion itself is not enough to allow prediction of future passing distance, as the latter requires direction of motion to be combined with knowledge of the current distance. Todd (1981) demonstrated the availability of visual information specifying whether a ball on a parabolic flight trajectory will eventually land behind or in front of the point of observation. Although this information does not provide a useful metric for perception of the future landing distance relative to the current position of the observer, it does specify the direction of movement (forward-backward) required for contact between the ball and the point of observation to occur.…”

mentioning

confidence: 99%

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Catching balls: How to get the hand to the right place at the right time.

Peper¹,

Bootsma²,

Mestre³

et al. 1994

Journal of Experimental Psychology: Human Perception and Perfor

240

297

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Information specifying the future passing distance of an approaching object is available (in units of object size) in the ratio of optical displacement velocity and optical expansion velocity. Despite empirical support for the assumption that object size can serve as a metric in the perception of passing distance, the present series of experiments reveals that in catching a ball subjects do not rely on such "point-predictive" information. The angle at which (real and simulated) balls approached the subject systematically affected verbal and manual estimates of future passing distance, as well as the kinematic characteristics of catching movements. To catch a ball, the actor uses momentary action-related information instead of spatiotemporal estimates. The hand velocity is geared to information specifying the currently required velocity. This secures ending up at the right place in the right time, regardless of where this may be.To be successful in interceptive actions, like catching or hitting a ball, the movement behavior of the actor has to be very precisely attuned to the spatiotemporal characteristics of the event. The timing of interceptive acts is generally considered to be based on visual information about the time remaining until the object reaches the observer. In line with Gibson's (1966Gibson's ( , 1979 notion of optical specification of information, Lee (1976) derived an optical quantity that specifies this "time-to-contact" (t c ), namely, the inverse of the relative rate of dilation of the ball's optical contour that is generated in the optic array by the relative approach between ball and point of observation. This optical quantity, termed r (tau), specifies the time remaining until the ball makes contact with the point of observation if velocity of

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“…τ is defined as the ratio of an object's instantaneous optical size to its instantaneous rate of optical expansion (Lee, 1976). Observers use or are sensitive to τ in a variety of tasks such as absolute and relative TTC judgments (e.g., (e.g., Bootsma & Oudejans, 1993;Schiff & Oldak, 1990;Todd, 1981). τ does not require perceptual estimates of the incoming object's absolute size, distance, or velocity.…”

mentioning

confidence: 99%

Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic, familiar scenes by older and younger adults

Keshavarz

Campos

DeLucia

et al. 2017

Atten Percept Psychophys

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Estimating time to contact (TTC) involves multiple sensory systems, including vision and audition. Previous findings suggested that the ratio of an object's instantaneous optical size/sound intensity to its instantaneous rate of change in optical size/sound intensity (τ) drives TTC judgments. Other evidence has shown that heuristic-based cues are used, including final optical size or final sound pressure level. Most previous studies have used decontextualized and unfamiliar stimuli (e.g., geometric shapes on a blank background). Here we evaluated TTC estimates by using a traffic scene with an approaching vehicle to evaluate the weights of visual and auditory TTC cues under more realistic conditions. Younger (18-39 years) and older (65+ years) participants made TTC estimates in three sensory conditions: visual-only, auditory-only, and audio-visual. Stimuli were presented within an immersive virtual-reality environment, and cue weights were calculated for both visual cues (e.g., visual τ, final optical size) and auditory cues (e.g., auditory τ, final sound pressure level). The results demonstrated the use of visual τ as well as heuristic cues in the visual-only condition. TTC estimates in the auditory-only condition, however, were primarily based on an auditory heuristic cue (final sound pressure level), rather than on auditory τ. In the audio-visual condition, the visual cues dominated overall, with the highest weight being assigned to visual τ by younger adults, and a more equal weighting of visual τ and heuristic cues in older adults. Overall, better characterizing the effects of combined sensory inputs, stimulus characteristics, and age on the cues used to estimate TTC will provide important insights into how these factors may affect everyday behavior.

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Visual information about moving objects.

Cited by 280 publications

References 47 publications

Timing an attacking forehand drive in table tennis.

Timing an attacking forehand drive in table tennis.

Catching balls: How to get the hand to the right place at the right time.

Estimating the relative weights of visual and auditory tau versus heuristic-based cues for time-to-contact judgments in realistic, familiar scenes by older and younger adults

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