Visually timed action: time-out for ‘tau’?

doi:10.1016/S1364-6613(99)01352-2

Trends in Cognitive Sciences

Volume 3, Issue 8, 1 August 1999, Pages 301-310

https://doi.org/10.1016/S1364-6613(99)01352-2 Get rights and content

Abstract

Bringing about desirable collisions (making interceptions) and avoiding unwanted collisions are critically important sensorimotor skills, which appear to require us to estimate the time remaining before collision occurs (time-to-collision). Until recently the theoretical approach to understanding time-to-collision estimation has been dominated by the tau-hypothesis, which has its origins in J.J. Gibson’s ecological approach to perception. The hypothesis proposes that a quantity (tau), present in the visual stimulus, provides the necessary time-to-collision information. Empirical results and formal analyses have now accumulated to demonstrate conclusively that the tau-hypothesis is false. This article describes an alternative approach that is based on recent data showing that the information used in judging time-to-collision is task- and situation-dependent, is of many different origins (of which tau is just one) and is influenced by the information-processing constraints of the nervous system.

Section snippets

Why the τ-hypothesis is false

Reasons for rejecting the τ-hypothesis derive from direct experimental tests and logical arguments based on empirical observations. To address the latter first: τ is limited as a source of TTC information by four factors: (1) it neglects accelerations; (2) it provides information about TTC with the eye; (3) it requires that an object be spherically symmetric; (4) it requires that the object’s image size and expansion rate be suprathreshold23, 24. These factors seriously restrict the utility of

What has been learned?

The theoretical problems with τ prompted a search for other sources of TTC information that could avoid them: this search was undertaken by Lee³⁴ and others19, 20, 24, 26. The first systematic attempt to solve the problems with τ was made by Tresilian¹⁹ who showed that accurate TTC information was available for use in bypass approaches (see Box 2); that methods are available for overcoming the problem with irregularly shaped rotating objects (if the object is rotating sufficiently fast,

Replacing the τ-hypothesis

The picture of TTC perception that emerges from the work reviewed in the previous section is a complex one. A variety of perceptual variables can influence TTC perception and the influence of a given variable is task dependent: one task might use one set of variables and another task a completely different set. A theory like the τ-hypothesis, which attempts to account for all TTC judgments in the same way is untenable. At the opposite extreme is the view that no theory is possible, merely a

Using information to control a response

Not only do different tasks involve different sources of information but the way in which the information is used in the control of the response is likely to differ between tasks and to change with experience and practice. A body of evidence – behavioural61, 62, neurological⁶² and neuroanatomical62, 63 – supports the idea that there are at least two functional streams of visual information processing within primate (including human) neocortex62, 63. These streams appear to support different

Conclusions

This article has reviewed recent work that shows conclusively that the hypothesis which proposes the variable τ as the informational basis for TTC estimation is false. Instead, it is clear that τ is a component of a more complex picture and it may or may not contribute to performance in a particular task. A new framework for understanding TTC perception, very different from the Gibsonian τ-hypothesis, is outlined here. This framework is based, firstly, upon results that demonstrate that many

Outstanding questions

•
How do the requirements for temporal accuracy vary between tasks and what perceptual quantities are available to provide the timing information necessary to explain observed levels of performance? How do these requirements constrain the selection and integration of TTC related information? What other factors affect selection and integration?
•
Exactly what sources of TTC information in addition to τ can the nervous system detect and how are they detected? Some suggestions have been proposed and

Acknowledgements

My thanks to James Cutting, Guy Wallis and two anonymous referees for helpful comment on previous versions of the manuscript. Preparation of this manuscript was supported by the Australian Research Council.

References (66)

D. Regan
Visual judgments and misjudgments in cricket and the art of flight
Perception
(1992)
J.J. Gibson
Ecological optics
Vis. Res.
(1961)
R.J. Bootsma et al.
Timing an attacking forehand drive in table tennis
J. Exp. Psychol. Hum. Percept. Perform.
(1990)
J.R. Tresilian
Perceptual information for the timing of interceptive action
Perception
(1990)
J.R. Tresilian
Approximate information sources and perceptual variables in interceptive timing
J. Exp. Psychol. Hum. Percept. Perform.
(1994)
T. Stanard
Visual information used in collision avoidance tasks: the importance of understanding the dynamics of action
J.R. Tresilian
Perceptual and cognitive processes in time-to-collision estimation: analysis of prediction-motion and relative judgment tasks
Percept. Psychophys.
(1995)
J.B.J. Smeets et al.
Perception and action are based on the same visual information: distinction between position and velocity
J. Exp. Psychol. Hum. Percept. Perform.
(1995)
D.W. Massaro
Ambiguity in perception and experimentation
J. Exp. Psychol. Gen.
(1988)
A.D. Milner et al.
The Visual Brain in Action
(1992)

R.J. Bootsma

On the information-based regulation of movement: what Wann (1996) may want to consider

J. Exp. Psychol. Hum. Percept. Perform.

(1997)

F. Hoyle

The Black Cloud

(1957)

D.N. Lee

A theory of the visual control of braking based on information about time-to-collision

Perception

(1976)

D.N. Lee

Visuo-motor coordination in space-time

M.T. Turvey et al.

The ecological approach to perceiving-acting

Acta Psychol.

(1986)

D.N. Lee et al.

Plummeting gannets: a paradigm of ecological optics

Nature

(1981)

D.N. Lee

Visual timing in hitting an accelerating ball

Q. J. Exp. Psychol.

(1983)

H. Wagner

Flow field variables trigger landing in flies

Nature

(1982)

M.N.O. Davies et al.

Optic flow field variables trigger landing in hawks but not in pigeons

Naturwissenschaften

(1990)

G.J.P. Savelsbergh et al.

Grasping tau

J. Exp. Psychol. Hum. Percept. Perform.

(1991)

G.J.P. Savelsbergh

The visual guidance of catching

Exp. Brain Res.

(1993)

M.K. Kaiser et al.

Optical specification of time to passage: observers’ sensitivity to global tau

J. Exp. Psychol. Hum. Percept. Perform.

(1993)

D. Regan et al.

Dissociation of discrimination thresholds for time to contact and rate of angular expansion

Vis. Res.

(1993)

Y. Wang et al.

Time to collision is signalled by neurons in the nucleus rotundus of pigeons

Nature

(1992)

H.J. Sun et al.

Computation of different optical variables of looming objects in pigeon nucleus rotundus neurons

Nat. Neurosci.

(1998)

F. Lacquaniti et al.

The role of vision in tuning anticipatory motor responses of the limbs

J.R. Tresilian

Four questions of time-to-contact: an analysis of research in interceptive timing

Perception

(1993)

J.P. Wann

Anticipating arrival: is the tau-margin a specious theory?

J. Exp. Psychol. Hum. Percept. Perform.

(1996)

D. Regan et al.

Binocular and monocular stimuli for motion in depth: changing-disparity and changing-size feed the same motion-in-depth stage

Vis. Res.

(1979)

R. Gray et al.

Accuracy of estimating time to collision using binocular and monocular information

Vis. Res.

(1998)

C. Von Hofsten

Catching skills in infancy

J. Exp. Psychol. Hum. Percept. Perform.

(1983)

R.J. Bootsma et al.

Visual information about time to collision between two objects

J. Exp. Psychol. Hum. Percept. Perform.

(1993)

P.R. DeLucia

Pictorial and motion based information for depth perception

J. Exp. Psychol. Hum. Percept. Perform.

(1991)

Cited by (189)

The timing and amplitude of the muscular activity of the arms preceding impact in a forward fall is modulated with fall velocity
2023, Journal of Biomechanics
Protective arm reactions have been shown to be an important injury avoidance mechanism in unavoidable falls. Protective arm reactions have been shown to be modulated with fall height, however it is not clear if they are modulated with impact velocity. The aim of this study was to determine if protective arm reactions are modulated in response to a forward fall with an initially unpredictable impact velocity. Forward falls were evoked via sudden release of a standing pendulum support frame with adjustable counterweight to control fall acceleration and impact velocity. Thirteen younger adults (1 female) participated in this study. Counterweight load explained more than 89% of the variation of impact velocity. Angular velocity at impact decreased (p < 0.001), drop duration increased from 601 ms to 816 ms (p < 0.001), and the maximum vertical ground reaction force decreased from 64%BW to 46%BW (p < 0.001) between the small and large counterweight. Elbow angle at impact (129 degrees extension), triceps (119 ms) and biceps (98 ms) pre-impact time, and co-activation (57%) were not significantly affected by counterweight load (p-values > 0.08). Average triceps and biceps EMG amplitude decreased from 0.26 V/V to 0.19 V/V (p = 0.004) and 0.24 V/V to 0.11 V/V (p = 0.002) with increasing counterweight respectively. Protective arm reactions were modulated with fall velocity by reducing EMG amplitude with decreasing impact velocity. This demonstrates a neuromotor control strategy for managing evolving fall conditions. Future work is needed to further understand how the CNS deals with additional unpredictability (e.g., fall direction, perturbation magnitude, etc.) when deploying protective arm reactions.
Visual information of vehicle velocity acquired by pedestrians involved in road crossing accidents
2021, Accident Analysis and Prevention
This paper describes a geometric optical relationship between the perceived visual information of approaching vehicles by pedestrians who intend to cross the road and the factors underlying pedestrian accidents in Japan. We create a model based on this visual information, wherein the retinal image corresponding to vehicle velocity perception is broken down into tangential components and normal components in a two-dimensional polar coordinate system that employs the nodal point of the eyeball as the origin. Our visual model uses the relationship between the tangential and normal components of the velocity to calculate the distance at which the velocity of the vehicle can be perceived by pedestrians. The maximum distance at which vehicle velocity can be perceived by pedestrians derived from the visual model is consistent with the timing at which a vehicle collides with a pedestrian most frequently in the pedestrian accidents gleaned from accident statistics. The result of the simulation of the visual model showed that the eye height of the pedestrian, the total height of the vehicle and the sensory threshold of motion determine the components by which the maximum perception distance of the vehicle velocity is given. These findings contribute to the enhancement of safety measures in traffic accidents from the pedestrian’s perspective.
Deceleration parameters and their applicability as informal communication signal between pedestrians and automated vehicles
2019, Transportation Research Part F: Traffic Psychology and Behaviour
The proportion of automated vehicles is predicted to steadily increase within the next years. This development is accompanied by several challenges, like the communication between automated vehicles and vulnerable road users, such as pedestrians. The current communication strategies involving the driver, will lose their functionality when interacting with automated vehicles. Due to that, this study focused on vehicle deceleration as informal communication cue. We tested specific parameters (deceleration rate, vehicle speed, onset of deceleration, vehicle size and daylight) within two experimental, video-based simulations in regard to detection performance. Results showed significant shorter reaction times for higher deceleration rate and lower speed. Results for vehicle size and onset of deceleration were mostly influenced by interactions among the parameters. Day light condition did not reveal significance. Within the discussion, we argue to support future communication between automated vehicles and pedestrians by applying smooth and early decelerations, that incorporate vehicle speed as well as vehicle size.
Does Knowledge of Results Affect Motor Skill Learning and Adaptation in Interception-Like Tasks?
2024, Journal of Motor Learning and Development
Hardware Implementation of Ultra-Fast Obstacle Avoidance Based on a Single Photonic Spiking Neuron
2023, Laser and Photonics Reviews
Expecting pain
2023, Synthese

View all citing articles on Scopus

View full text

Trends in Cognitive Sciences

ReviewVisually timed action: time-out for ‘tau’?

Abstract

Section snippets

Why the τ-hypothesis is false

What has been learned?

Replacing the τ-hypothesis

Using information to control a response

Conclusions

Outstanding questions

Acknowledgements

Perception

Vis. Res.

J. Exp. Psychol. Hum. Percept. Perform.

Perception

J. Exp. Psychol. Hum. Percept. Perform.

Percept. Psychophys.

J. Exp. Psychol. Hum. Percept. Perform.

J. Exp. Psychol. Gen.

J. Exp. Psychol. Hum. Percept. Perform.

The Black Cloud

A theory of the visual control of braking based on information about time-to-collision

Perception

Visuo-motor coordination in space-time

The ecological approach to perceiving-acting

Acta Psychol.

Plummeting gannets: a paradigm of ecological optics

Nature

Visual timing in hitting an accelerating ball

Q. J. Exp. Psychol.

Flow field variables trigger landing in flies

Nature

Optic flow field variables trigger landing in hawks but not in pigeons

Naturwissenschaften

Grasping tau

J. Exp. Psychol. Hum. Percept. Perform.

The visual guidance of catching

Exp. Brain Res.

Optical specification of time to passage: observers’ sensitivity to global tau

J. Exp. Psychol. Hum. Percept. Perform.

Dissociation of discrimination thresholds for time to contact and rate of angular expansion

Vis. Res.

Time to collision is signalled by neurons in the nucleus rotundus of pigeons

Nature

Computation of different optical variables of looming objects in pigeon nucleus rotundus neurons

Nat. Neurosci.

The role of vision in tuning anticipatory motor responses of the limbs

Four questions of time-to-contact: an analysis of research in interceptive timing

Perception

Anticipating arrival: is the tau-margin a specious theory?

J. Exp. Psychol. Hum. Percept. Perform.

Binocular and monocular stimuli for motion in depth: changing-disparity and changing-size feed the same motion-in-depth stage

Vis. Res.

Accuracy of estimating time to collision using binocular and monocular information

Vis. Res.

Catching skills in infancy

J. Exp. Psychol. Hum. Percept. Perform.

Visual information about time to collision between two objects

J. Exp. Psychol. Hum. Percept. Perform.

Pictorial and motion based information for depth perception

J. Exp. Psychol. Hum. Percept. Perform.

Review
Visually timed action: time-out for ‘tau’?