Abstract

We measured motion-detection and motion-discrimination performance for different directions of motion, using stochastic motion sequences. Random-dot cinematograms containing 200 dots in a circular aperture were used as stimuli in a two-interval forced-choice procedure. In the motion-detection experiment, observers judged which of two intervals contained weak coherent motion, the other interval containing random motion only. In the direction-discrimination experiment, observers viewed a standard direction of motion followed by comparison motion in a slightly different direction. Observers indicated whether the comparison was clockwise or counterclockwise, relative to the standard. Twelve directions of motion were tested in the detection task and five standard directions (three cardinal directions and two oblique directions) in the discrimination task. Detection thresholds were invariant with direction of motion, but direction-discrimination thresholds were significantly higher for motion in oblique directions, even at low-coherence levels. Results from control conditions ruled out monitor artifacts and indicate that the oblique effect is relative to retinal coordinates. These results have broad implications for computational and physiological models of motion perception.

© 1998 Optical Society of America

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  1. S. Appelle, “Perception and discrimination as a function of stimulus orientation: the oblique effect in man and animals,” Psychol. Bull. 78, 266–278 (1972).
    [CrossRef] [PubMed]
  2. R. J. W. Mansfield, “Neural basis of orientation perception in primate vision,” Science 188, 1133–1135 (1974).
    [CrossRef]
  3. D. Rose, C. B. Blakemore, “An analysis of orientation selectivity in the cat’s visual cortex,” Exp. Brain Res. 20, 1–17 (1974).
    [CrossRef] [PubMed]
  4. B. Breitmeyer, B. Julesz, W. Kropfl, “Dynamic random-dot stereograms reveal up–down anisotropy and left–right isotropy between cortical hemifields,” Science 187, 269–270 (1975).
    [CrossRef] [PubMed]
  5. K. Ball, R. Sekuler, “Masking of motion by broad-band and filtered directional noise,” Percept. Psychophys. 26, 206–214 (1979).
    [CrossRef]
  6. E. Levinson, R. Sekuler, “A two-dimensional analysis of direction-specific adaptation,” Vision Res. 20, 103–108 (1980).
    [CrossRef] [PubMed]
  7. W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
    [CrossRef] [PubMed]
  8. J. E. Raymond, “Directional anisotropy of motion sensitivity across the visual field,” Vision Res. 34, 1029–1038 (1994).
    [CrossRef] [PubMed]
  9. K. Ball, R. Sekuler, “Models of stimulus uncertainty in motion perception,” Psychol. Rev. 87, 435–469 (1980).
    [CrossRef] [PubMed]
  10. K. Ball, R. Sekuler, “A specific and enduring improvement in visual motion discrimination,” Science 218, 697–698 (1982).
    [CrossRef] [PubMed]
  11. N. Matthews, L. Welch, “Velocity-dependent improvements in single-dot direction discrimination,” Percept. Psychophys. 59, 60–72 (1997).
    [CrossRef] [PubMed]
  12. E. Hiris, R. Blake, “Direction repulsion in motion transparency,” Visual Neurosci. 13, 187–197 (1996).
    [PubMed]
  13. W. Marshak, R. Sekuler, “Mutual repulsion between moving visual targets,” Science 205, 1399–1401 (1979).
    [CrossRef] [PubMed]
  14. D. W. Williams, R. Sekuler, “Coherent global motion percepts from stochastic local motions,” Vision Res. 24, 55–62 (1984).
    [CrossRef] [PubMed]
  15. K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
    [PubMed]
  16. B. F. Green, “Figure coherence in the kinetic depth effect,” J. Exp. Psychol. 62, 272–282 (1961).
    [CrossRef] [PubMed]
  17. M. L. Braunstein, Depth Perception through Motion (Academic, New York, 1976).
  18. E. Levinson, R. Sekuler, “Adaptation alters perceived direction of motion,” Vision Res. 16, 779–781 (1976).
    [CrossRef] [PubMed]
  19. W. T. Newsome, E. B. Pare, “A selective impairment of motion perception following lesions of the middle temporal visual area (MT),” J. Neurosci. 8, 2201–2211 (1988).
    [PubMed]
  20. M. Edwards, D. R. Badcock, “Global motion perception: interaction of the ON and OFF pathways,” Vision Res. 34, 2849–2858 (1994); R. Blake, T. S. Aiba, “Detection and discrimination of optical flow components,” Jap. Psychol. Res. 40, 19–30 (1998).
    [CrossRef] [PubMed]
  21. L. T. Maloney, “Confidence intervals for the parameters of psychometric functions,” Percept. Psychophys. 47, 127–134 (1990).
    [CrossRef] [PubMed]
  22. B. de Bruyn, G. A. Orban, “Human velocity and direction discrimination measured with random dot patterns,” Vision Res. 28, 1323–1335 (1988).
    [CrossRef]
  23. S. N. J. Watamaniuk, R. Sekuler, D. W. Williams, “Direction perception in complex dynamic displays, the integration of direction information,” Vision Res. 29, 47–59 (1989).
    [CrossRef]
  24. R. Blake, N. J. Cepeda, E. Hiris, “Memory for visual motion,” J. Exp. Psychol. Human Percept. Perf. 23, 353–369 (1997).
    [CrossRef]
  25. T. D. Albright, “Direction and orientation selectivity of neurons in visual area MT of the macaque,” J. Neurophysiol. 52, 1106–1130 (1984).
    [PubMed]
  26. M. Edwards, D. Badcock, “Asymmetries in the sensitivity to motion in depth: a centripetal bias,” Perception 22, 1013–1023 (1993).
    [CrossRef] [PubMed]
  27. R. J. Snowden, A. B. Milne, “The effects of adapting to complex motions: position invariance and tuning to spiral motions,” J. Cog. Neurosci. 8, 435–452 (1996).
    [CrossRef]
  28. V. P. Ferrera, H. R. Wilson, “Perceived direction of moving two-dimensional patterns,” Vision Res. 30, 273–288 (1990).
    [CrossRef] [PubMed]
  29. D. W. Heeley, H. M. Buchanan-Smith, “Directional acuity for drifting plaids,” Vision Res. 32, 97–104 (1992).
    [CrossRef] [PubMed]
  30. N. J. Coletta, P. Segu, C. L. M. Tiana, “An oblique effect in parafoveal motion perception,” Vision Res. 33, 2747–2756 (1993).
    [CrossRef] [PubMed]
  31. D. Williams, S. Tweten, R. Sekuler, “Using metamers to explore motion perception,” Vision Res. 31, 275–286 (1991).
    [CrossRef] [PubMed]
  32. H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
    [CrossRef]
  33. A. Grunewald, M. J. M. Lankheet, “Orthogonal motion after-effect illusion predicted by a model of cortical motion processing,” Nature 384, 358–360 (1996).
    [CrossRef] [PubMed]
  34. We have not addressed models that describe the registration of Fourier motion35 and nonFourier motion,32,36 because these models focus on the design of motion sensing units and not their role in signalling direction of coherent motion. Nor do we examine models designed to account for structure from motion37 or registration of complex optic flow,38 for these models are agnostic with respect to oblique effects in motion perception.
  35. E. H. Adelson, J. R. Bergen, “Spatiotemporal energy models for the perception of motion,” J. Opt. Soc. Am. A 2, 284–299 (1985);J. P. H. van Santen, G. Sperling, “Elaborated Reichardt detectors,” J. Opt. Soc. Am. A 2, 300–321 (1985);A. B. Watson, A. J. Ahumada, “Model of human visual-motion sensing,” J. Opt. Soc. Am. A 2, 322–341 (1985).
    [CrossRef] [PubMed]
  36. C. Chubb, G. Sperling, “Drift-balanced random stimuli: a general basis for studying non-Fourier motion perception,” J. Opt. Soc. Am. A 5, 1986–2007 (1988).
    [CrossRef] [PubMed]
  37. See, e.g., S. Ullman, The Interpretation of Visual Motion (MIT Press, Cambridge, Mass., 1979).
  38. J. J. Koenderink, A. van Doorn, “Local structure of movement parallax of the plane,” J. Opt. Soc. Am. 66, 717–723 (1976).
    [CrossRef]
  39. D. Williams, G. Phillips, R. Sekuler, “Hysteresis in the perception of motion direction as evidence for neural cooperativity,” Nature 324, 253–255 (1986).
    [CrossRef] [PubMed]
  40. D. Williams, G. Phillips, “Cooperative phenomena in the perception of motion direction,” J. Opt. Soc. Am. A 4, 878–885 (1987).
    [CrossRef] [PubMed]
  41. E. Hiris, R. Blake, “Discrimination of coherent motion when local motion varies in speed and direction,” J. Exp. Psychol. Human Percept. Perf. 21, 308–317 (1995).
    [CrossRef]
  42. V. P. Ferrera, H. R. Wilson, “Perceived speed of moving two-dimensional patterns,” Vision Res. 31, 877–894 (1991).
    [CrossRef] [PubMed]
  43. J. Kim, H. R. Wilson, “Dependence of plaid motion coherence on component grating directions,” Vision Res. 33, 2479–2489 (1993);H. R. Wilson, J. Kim, “Perceived motion in the vector sum direction,” Vision Res. 34, 1835–1842 (1994).
    [CrossRef] [PubMed]
  44. H. R. Wilson, J. Kim, “A model for motion coherence and transparency,” Visual Neurosci. 11, 1205–1220 (1994).
    [CrossRef]
  45. E. Hiris, R. Blake, “Another perspective on the visual motion aftereffect,” Proc. Natl. Acad. Sci. USA 89, 9025–9028 (1992).
    [CrossRef] [PubMed]
  46. J. H. R. Maunsell, D. C. van Essen, “Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation,” J. Neurophysiol. 49, 1127–1147 (1983).
    [PubMed]
  47. T. D. Albright, “Centrifugal directional bias in the middle temporal visual area (MT) of the macaque,” Visual Neurosci. 2, 177–188 (1989).
    [CrossRef]
  48. K. Ball, R. Sekuler, “Human vision favors centrifugal motion,” Perception 9, 317–325 (1980).
    [CrossRef] [PubMed]
  49. H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

1997

N. Matthews, L. Welch, “Velocity-dependent improvements in single-dot direction discrimination,” Percept. Psychophys. 59, 60–72 (1997).
[CrossRef] [PubMed]

R. Blake, N. J. Cepeda, E. Hiris, “Memory for visual motion,” J. Exp. Psychol. Human Percept. Perf. 23, 353–369 (1997).
[CrossRef]

1996

R. J. Snowden, A. B. Milne, “The effects of adapting to complex motions: position invariance and tuning to spiral motions,” J. Cog. Neurosci. 8, 435–452 (1996).
[CrossRef]

A. Grunewald, M. J. M. Lankheet, “Orthogonal motion after-effect illusion predicted by a model of cortical motion processing,” Nature 384, 358–360 (1996).
[CrossRef] [PubMed]

E. Hiris, R. Blake, “Direction repulsion in motion transparency,” Visual Neurosci. 13, 187–197 (1996).
[PubMed]

1995

E. Hiris, R. Blake, “Discrimination of coherent motion when local motion varies in speed and direction,” J. Exp. Psychol. Human Percept. Perf. 21, 308–317 (1995).
[CrossRef]

1994

M. Edwards, D. R. Badcock, “Global motion perception: interaction of the ON and OFF pathways,” Vision Res. 34, 2849–2858 (1994); R. Blake, T. S. Aiba, “Detection and discrimination of optical flow components,” Jap. Psychol. Res. 40, 19–30 (1998).
[CrossRef] [PubMed]

J. E. Raymond, “Directional anisotropy of motion sensitivity across the visual field,” Vision Res. 34, 1029–1038 (1994).
[CrossRef] [PubMed]

H. R. Wilson, J. Kim, “A model for motion coherence and transparency,” Visual Neurosci. 11, 1205–1220 (1994).
[CrossRef]

1993

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
[PubMed]

J. Kim, H. R. Wilson, “Dependence of plaid motion coherence on component grating directions,” Vision Res. 33, 2479–2489 (1993);H. R. Wilson, J. Kim, “Perceived motion in the vector sum direction,” Vision Res. 34, 1835–1842 (1994).
[CrossRef] [PubMed]

M. Edwards, D. Badcock, “Asymmetries in the sensitivity to motion in depth: a centripetal bias,” Perception 22, 1013–1023 (1993).
[CrossRef] [PubMed]

N. J. Coletta, P. Segu, C. L. M. Tiana, “An oblique effect in parafoveal motion perception,” Vision Res. 33, 2747–2756 (1993).
[CrossRef] [PubMed]

1992

D. W. Heeley, H. M. Buchanan-Smith, “Directional acuity for drifting plaids,” Vision Res. 32, 97–104 (1992).
[CrossRef] [PubMed]

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

E. Hiris, R. Blake, “Another perspective on the visual motion aftereffect,” Proc. Natl. Acad. Sci. USA 89, 9025–9028 (1992).
[CrossRef] [PubMed]

1991

V. P. Ferrera, H. R. Wilson, “Perceived speed of moving two-dimensional patterns,” Vision Res. 31, 877–894 (1991).
[CrossRef] [PubMed]

D. Williams, S. Tweten, R. Sekuler, “Using metamers to explore motion perception,” Vision Res. 31, 275–286 (1991).
[CrossRef] [PubMed]

1990

L. T. Maloney, “Confidence intervals for the parameters of psychometric functions,” Percept. Psychophys. 47, 127–134 (1990).
[CrossRef] [PubMed]

V. P. Ferrera, H. R. Wilson, “Perceived direction of moving two-dimensional patterns,” Vision Res. 30, 273–288 (1990).
[CrossRef] [PubMed]

1989

S. N. J. Watamaniuk, R. Sekuler, D. W. Williams, “Direction perception in complex dynamic displays, the integration of direction information,” Vision Res. 29, 47–59 (1989).
[CrossRef]

T. D. Albright, “Centrifugal directional bias in the middle temporal visual area (MT) of the macaque,” Visual Neurosci. 2, 177–188 (1989).
[CrossRef]

1988

C. Chubb, G. Sperling, “Drift-balanced random stimuli: a general basis for studying non-Fourier motion perception,” J. Opt. Soc. Am. A 5, 1986–2007 (1988).
[CrossRef] [PubMed]

W. T. Newsome, E. B. Pare, “A selective impairment of motion perception following lesions of the middle temporal visual area (MT),” J. Neurosci. 8, 2201–2211 (1988).
[PubMed]

B. de Bruyn, G. A. Orban, “Human velocity and direction discrimination measured with random dot patterns,” Vision Res. 28, 1323–1335 (1988).
[CrossRef]

1987

1986

D. Williams, G. Phillips, R. Sekuler, “Hysteresis in the perception of motion direction as evidence for neural cooperativity,” Nature 324, 253–255 (1986).
[CrossRef] [PubMed]

1985

1984

T. D. Albright, “Direction and orientation selectivity of neurons in visual area MT of the macaque,” J. Neurophysiol. 52, 1106–1130 (1984).
[PubMed]

D. W. Williams, R. Sekuler, “Coherent global motion percepts from stochastic local motions,” Vision Res. 24, 55–62 (1984).
[CrossRef] [PubMed]

1983

J. H. R. Maunsell, D. C. van Essen, “Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation,” J. Neurophysiol. 49, 1127–1147 (1983).
[PubMed]

1982

K. Ball, R. Sekuler, “A specific and enduring improvement in visual motion discrimination,” Science 218, 697–698 (1982).
[CrossRef] [PubMed]

1980

K. Ball, R. Sekuler, “Models of stimulus uncertainty in motion perception,” Psychol. Rev. 87, 435–469 (1980).
[CrossRef] [PubMed]

E. Levinson, R. Sekuler, “A two-dimensional analysis of direction-specific adaptation,” Vision Res. 20, 103–108 (1980).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Human vision favors centrifugal motion,” Perception 9, 317–325 (1980).
[CrossRef] [PubMed]

1979

K. Ball, R. Sekuler, “Masking of motion by broad-band and filtered directional noise,” Percept. Psychophys. 26, 206–214 (1979).
[CrossRef]

W. Marshak, R. Sekuler, “Mutual repulsion between moving visual targets,” Science 205, 1399–1401 (1979).
[CrossRef] [PubMed]

1976

E. Levinson, R. Sekuler, “Adaptation alters perceived direction of motion,” Vision Res. 16, 779–781 (1976).
[CrossRef] [PubMed]

J. J. Koenderink, A. van Doorn, “Local structure of movement parallax of the plane,” J. Opt. Soc. Am. 66, 717–723 (1976).
[CrossRef]

1975

B. Breitmeyer, B. Julesz, W. Kropfl, “Dynamic random-dot stereograms reveal up–down anisotropy and left–right isotropy between cortical hemifields,” Science 187, 269–270 (1975).
[CrossRef] [PubMed]

1974

R. J. W. Mansfield, “Neural basis of orientation perception in primate vision,” Science 188, 1133–1135 (1974).
[CrossRef]

D. Rose, C. B. Blakemore, “An analysis of orientation selectivity in the cat’s visual cortex,” Exp. Brain Res. 20, 1–17 (1974).
[CrossRef] [PubMed]

1972

S. Appelle, “Perception and discrimination as a function of stimulus orientation: the oblique effect in man and animals,” Psychol. Bull. 78, 266–278 (1972).
[CrossRef] [PubMed]

1961

B. F. Green, “Figure coherence in the kinetic depth effect,” J. Exp. Psychol. 62, 272–282 (1961).
[CrossRef] [PubMed]

Adelson, E. H.

Albright, T. D.

T. D. Albright, “Centrifugal directional bias in the middle temporal visual area (MT) of the macaque,” Visual Neurosci. 2, 177–188 (1989).
[CrossRef]

T. D. Albright, “Direction and orientation selectivity of neurons in visual area MT of the macaque,” J. Neurophysiol. 52, 1106–1130 (1984).
[PubMed]

Appelle, S.

S. Appelle, “Perception and discrimination as a function of stimulus orientation: the oblique effect in man and animals,” Psychol. Bull. 78, 266–278 (1972).
[CrossRef] [PubMed]

Badcock, D.

M. Edwards, D. Badcock, “Asymmetries in the sensitivity to motion in depth: a centripetal bias,” Perception 22, 1013–1023 (1993).
[CrossRef] [PubMed]

Badcock, D. R.

M. Edwards, D. R. Badcock, “Global motion perception: interaction of the ON and OFF pathways,” Vision Res. 34, 2849–2858 (1994); R. Blake, T. S. Aiba, “Detection and discrimination of optical flow components,” Jap. Psychol. Res. 40, 19–30 (1998).
[CrossRef] [PubMed]

Ball, K.

K. Ball, R. Sekuler, “A specific and enduring improvement in visual motion discrimination,” Science 218, 697–698 (1982).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Models of stimulus uncertainty in motion perception,” Psychol. Rev. 87, 435–469 (1980).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Human vision favors centrifugal motion,” Perception 9, 317–325 (1980).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Masking of motion by broad-band and filtered directional noise,” Percept. Psychophys. 26, 206–214 (1979).
[CrossRef]

Bergen, J. R.

Blake, R.

R. Blake, N. J. Cepeda, E. Hiris, “Memory for visual motion,” J. Exp. Psychol. Human Percept. Perf. 23, 353–369 (1997).
[CrossRef]

E. Hiris, R. Blake, “Direction repulsion in motion transparency,” Visual Neurosci. 13, 187–197 (1996).
[PubMed]

E. Hiris, R. Blake, “Discrimination of coherent motion when local motion varies in speed and direction,” J. Exp. Psychol. Human Percept. Perf. 21, 308–317 (1995).
[CrossRef]

E. Hiris, R. Blake, “Another perspective on the visual motion aftereffect,” Proc. Natl. Acad. Sci. USA 89, 9025–9028 (1992).
[CrossRef] [PubMed]

Blakemore, C. B.

D. Rose, C. B. Blakemore, “An analysis of orientation selectivity in the cat’s visual cortex,” Exp. Brain Res. 20, 1–17 (1974).
[CrossRef] [PubMed]

Braunstein, M. L.

M. L. Braunstein, Depth Perception through Motion (Academic, New York, 1976).

Breitmeyer, B.

B. Breitmeyer, B. Julesz, W. Kropfl, “Dynamic random-dot stereograms reveal up–down anisotropy and left–right isotropy between cortical hemifields,” Science 187, 269–270 (1975).
[CrossRef] [PubMed]

Britten, K. H.

K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
[PubMed]

Buchanan-Smith, H. M.

D. W. Heeley, H. M. Buchanan-Smith, “Directional acuity for drifting plaids,” Vision Res. 32, 97–104 (1992).
[CrossRef] [PubMed]

Cepeda, N. J.

R. Blake, N. J. Cepeda, E. Hiris, “Memory for visual motion,” J. Exp. Psychol. Human Percept. Perf. 23, 353–369 (1997).
[CrossRef]

Chubb, C.

Coletta, N. J.

N. J. Coletta, P. Segu, C. L. M. Tiana, “An oblique effect in parafoveal motion perception,” Vision Res. 33, 2747–2756 (1993).
[CrossRef] [PubMed]

de Bruyn, B.

B. de Bruyn, G. A. Orban, “Human velocity and direction discrimination measured with random dot patterns,” Vision Res. 28, 1323–1335 (1988).
[CrossRef]

De Valois, R.

H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

Edwards, M.

M. Edwards, D. R. Badcock, “Global motion perception: interaction of the ON and OFF pathways,” Vision Res. 34, 2849–2858 (1994); R. Blake, T. S. Aiba, “Detection and discrimination of optical flow components,” Jap. Psychol. Res. 40, 19–30 (1998).
[CrossRef] [PubMed]

M. Edwards, D. Badcock, “Asymmetries in the sensitivity to motion in depth: a centripetal bias,” Perception 22, 1013–1023 (1993).
[CrossRef] [PubMed]

Ferrera, V. P.

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

V. P. Ferrera, H. R. Wilson, “Perceived speed of moving two-dimensional patterns,” Vision Res. 31, 877–894 (1991).
[CrossRef] [PubMed]

V. P. Ferrera, H. R. Wilson, “Perceived direction of moving two-dimensional patterns,” Vision Res. 30, 273–288 (1990).
[CrossRef] [PubMed]

Green, B. F.

B. F. Green, “Figure coherence in the kinetic depth effect,” J. Exp. Psychol. 62, 272–282 (1961).
[CrossRef] [PubMed]

Grunewald, A.

A. Grunewald, M. J. M. Lankheet, “Orthogonal motion after-effect illusion predicted by a model of cortical motion processing,” Nature 384, 358–360 (1996).
[CrossRef] [PubMed]

Heeley, D. W.

D. W. Heeley, H. M. Buchanan-Smith, “Directional acuity for drifting plaids,” Vision Res. 32, 97–104 (1992).
[CrossRef] [PubMed]

Hiris, E.

R. Blake, N. J. Cepeda, E. Hiris, “Memory for visual motion,” J. Exp. Psychol. Human Percept. Perf. 23, 353–369 (1997).
[CrossRef]

E. Hiris, R. Blake, “Direction repulsion in motion transparency,” Visual Neurosci. 13, 187–197 (1996).
[PubMed]

E. Hiris, R. Blake, “Discrimination of coherent motion when local motion varies in speed and direction,” J. Exp. Psychol. Human Percept. Perf. 21, 308–317 (1995).
[CrossRef]

E. Hiris, R. Blake, “Another perspective on the visual motion aftereffect,” Proc. Natl. Acad. Sci. USA 89, 9025–9028 (1992).
[CrossRef] [PubMed]

Julesz, B.

B. Breitmeyer, B. Julesz, W. Kropfl, “Dynamic random-dot stereograms reveal up–down anisotropy and left–right isotropy between cortical hemifields,” Science 187, 269–270 (1975).
[CrossRef] [PubMed]

Kim, J.

H. R. Wilson, J. Kim, “A model for motion coherence and transparency,” Visual Neurosci. 11, 1205–1220 (1994).
[CrossRef]

J. Kim, H. R. Wilson, “Dependence of plaid motion coherence on component grating directions,” Vision Res. 33, 2479–2489 (1993);H. R. Wilson, J. Kim, “Perceived motion in the vector sum direction,” Vision Res. 34, 1835–1842 (1994).
[CrossRef] [PubMed]

Koenderink, J. J.

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

J. J. Koenderink, A. van Doorn, “Local structure of movement parallax of the plane,” J. Opt. Soc. Am. 66, 717–723 (1976).
[CrossRef]

Kropfl, W.

B. Breitmeyer, B. Julesz, W. Kropfl, “Dynamic random-dot stereograms reveal up–down anisotropy and left–right isotropy between cortical hemifields,” Science 187, 269–270 (1975).
[CrossRef] [PubMed]

Lankheet, M. J. M.

A. Grunewald, M. J. M. Lankheet, “Orthogonal motion after-effect illusion predicted by a model of cortical motion processing,” Nature 384, 358–360 (1996).
[CrossRef] [PubMed]

Levi, D.

H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

Levinson, E.

E. Levinson, R. Sekuler, “A two-dimensional analysis of direction-specific adaptation,” Vision Res. 20, 103–108 (1980).
[CrossRef] [PubMed]

E. Levinson, R. Sekuler, “Adaptation alters perceived direction of motion,” Vision Res. 16, 779–781 (1976).
[CrossRef] [PubMed]

Maffei, L.

H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

Maloney, L. T.

L. T. Maloney, “Confidence intervals for the parameters of psychometric functions,” Percept. Psychophys. 47, 127–134 (1990).
[CrossRef] [PubMed]

Mansfield, R. J. W.

R. J. W. Mansfield, “Neural basis of orientation perception in primate vision,” Science 188, 1133–1135 (1974).
[CrossRef]

Marshak, W.

W. Marshak, R. Sekuler, “Mutual repulsion between moving visual targets,” Science 205, 1399–1401 (1979).
[CrossRef] [PubMed]

Matthews, N.

N. Matthews, L. Welch, “Velocity-dependent improvements in single-dot direction discrimination,” Percept. Psychophys. 59, 60–72 (1997).
[CrossRef] [PubMed]

Maunsell, J. H. R.

J. H. R. Maunsell, D. C. van Essen, “Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation,” J. Neurophysiol. 49, 1127–1147 (1983).
[PubMed]

Milders, M. V.

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

Milne, A. B.

R. J. Snowden, A. B. Milne, “The effects of adapting to complex motions: position invariance and tuning to spiral motions,” J. Cog. Neurosci. 8, 435–452 (1996).
[CrossRef]

Movshon, J. A.

K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
[PubMed]

Newsome, W. T.

K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
[PubMed]

W. T. Newsome, E. B. Pare, “A selective impairment of motion perception following lesions of the middle temporal visual area (MT),” J. Neurosci. 8, 2201–2211 (1988).
[PubMed]

Orban, G. A.

B. de Bruyn, G. A. Orban, “Human velocity and direction discrimination measured with random dot patterns,” Vision Res. 28, 1323–1335 (1988).
[CrossRef]

Pare, E. B.

W. T. Newsome, E. B. Pare, “A selective impairment of motion perception following lesions of the middle temporal visual area (MT),” J. Neurosci. 8, 2201–2211 (1988).
[PubMed]

Phillips, G.

D. Williams, G. Phillips, “Cooperative phenomena in the perception of motion direction,” J. Opt. Soc. Am. A 4, 878–885 (1987).
[CrossRef] [PubMed]

D. Williams, G. Phillips, R. Sekuler, “Hysteresis in the perception of motion direction as evidence for neural cooperativity,” Nature 324, 253–255 (1986).
[CrossRef] [PubMed]

Raymond, J. E.

J. E. Raymond, “Directional anisotropy of motion sensitivity across the visual field,” Vision Res. 34, 1029–1038 (1994).
[CrossRef] [PubMed]

Rose, D.

D. Rose, C. B. Blakemore, “An analysis of orientation selectivity in the cat’s visual cortex,” Exp. Brain Res. 20, 1–17 (1974).
[CrossRef] [PubMed]

Rovamo, J.

H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

Segu, P.

N. J. Coletta, P. Segu, C. L. M. Tiana, “An oblique effect in parafoveal motion perception,” Vision Res. 33, 2747–2756 (1993).
[CrossRef] [PubMed]

Sekuler, R.

D. Williams, S. Tweten, R. Sekuler, “Using metamers to explore motion perception,” Vision Res. 31, 275–286 (1991).
[CrossRef] [PubMed]

S. N. J. Watamaniuk, R. Sekuler, D. W. Williams, “Direction perception in complex dynamic displays, the integration of direction information,” Vision Res. 29, 47–59 (1989).
[CrossRef]

D. Williams, G. Phillips, R. Sekuler, “Hysteresis in the perception of motion direction as evidence for neural cooperativity,” Nature 324, 253–255 (1986).
[CrossRef] [PubMed]

D. W. Williams, R. Sekuler, “Coherent global motion percepts from stochastic local motions,” Vision Res. 24, 55–62 (1984).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “A specific and enduring improvement in visual motion discrimination,” Science 218, 697–698 (1982).
[CrossRef] [PubMed]

E. Levinson, R. Sekuler, “A two-dimensional analysis of direction-specific adaptation,” Vision Res. 20, 103–108 (1980).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Models of stimulus uncertainty in motion perception,” Psychol. Rev. 87, 435–469 (1980).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Human vision favors centrifugal motion,” Perception 9, 317–325 (1980).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Masking of motion by broad-band and filtered directional noise,” Percept. Psychophys. 26, 206–214 (1979).
[CrossRef]

W. Marshak, R. Sekuler, “Mutual repulsion between moving visual targets,” Science 205, 1399–1401 (1979).
[CrossRef] [PubMed]

E. Levinson, R. Sekuler, “Adaptation alters perceived direction of motion,” Vision Res. 16, 779–781 (1976).
[CrossRef] [PubMed]

Shadlen, M. N.

K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
[PubMed]

Snowden, R. J.

R. J. Snowden, A. B. Milne, “The effects of adapting to complex motions: position invariance and tuning to spiral motions,” J. Cog. Neurosci. 8, 435–452 (1996).
[CrossRef]

Sperling, G.

Tiana, C. L. M.

N. J. Coletta, P. Segu, C. L. M. Tiana, “An oblique effect in parafoveal motion perception,” Vision Res. 33, 2747–2756 (1993).
[CrossRef] [PubMed]

Tweten, S.

D. Williams, S. Tweten, R. Sekuler, “Using metamers to explore motion perception,” Vision Res. 31, 275–286 (1991).
[CrossRef] [PubMed]

Ullman, S.

See, e.g., S. Ullman, The Interpretation of Visual Motion (MIT Press, Cambridge, Mass., 1979).

van de Grind, W. A.

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

van Doorn, A.

van Doorn, A. J.

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

van Essen, D. C.

J. H. R. Maunsell, D. C. van Essen, “Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation,” J. Neurophysiol. 49, 1127–1147 (1983).
[PubMed]

Voerman, H.

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

Watamaniuk, S. N. J.

S. N. J. Watamaniuk, R. Sekuler, D. W. Williams, “Direction perception in complex dynamic displays, the integration of direction information,” Vision Res. 29, 47–59 (1989).
[CrossRef]

Welch, L.

N. Matthews, L. Welch, “Velocity-dependent improvements in single-dot direction discrimination,” Percept. Psychophys. 59, 60–72 (1997).
[CrossRef] [PubMed]

Williams, D.

D. Williams, S. Tweten, R. Sekuler, “Using metamers to explore motion perception,” Vision Res. 31, 275–286 (1991).
[CrossRef] [PubMed]

D. Williams, G. Phillips, “Cooperative phenomena in the perception of motion direction,” J. Opt. Soc. Am. A 4, 878–885 (1987).
[CrossRef] [PubMed]

D. Williams, G. Phillips, R. Sekuler, “Hysteresis in the perception of motion direction as evidence for neural cooperativity,” Nature 324, 253–255 (1986).
[CrossRef] [PubMed]

Williams, D. W.

S. N. J. Watamaniuk, R. Sekuler, D. W. Williams, “Direction perception in complex dynamic displays, the integration of direction information,” Vision Res. 29, 47–59 (1989).
[CrossRef]

D. W. Williams, R. Sekuler, “Coherent global motion percepts from stochastic local motions,” Vision Res. 24, 55–62 (1984).
[CrossRef] [PubMed]

Wilson, H. R.

H. R. Wilson, J. Kim, “A model for motion coherence and transparency,” Visual Neurosci. 11, 1205–1220 (1994).
[CrossRef]

J. Kim, H. R. Wilson, “Dependence of plaid motion coherence on component grating directions,” Vision Res. 33, 2479–2489 (1993);H. R. Wilson, J. Kim, “Perceived motion in the vector sum direction,” Vision Res. 34, 1835–1842 (1994).
[CrossRef] [PubMed]

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

V. P. Ferrera, H. R. Wilson, “Perceived speed of moving two-dimensional patterns,” Vision Res. 31, 877–894 (1991).
[CrossRef] [PubMed]

V. P. Ferrera, H. R. Wilson, “Perceived direction of moving two-dimensional patterns,” Vision Res. 30, 273–288 (1990).
[CrossRef] [PubMed]

H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

Yo, C.

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

Exp. Brain Res.

D. Rose, C. B. Blakemore, “An analysis of orientation selectivity in the cat’s visual cortex,” Exp. Brain Res. 20, 1–17 (1974).
[CrossRef] [PubMed]

J. Cog. Neurosci.

R. J. Snowden, A. B. Milne, “The effects of adapting to complex motions: position invariance and tuning to spiral motions,” J. Cog. Neurosci. 8, 435–452 (1996).
[CrossRef]

J. Exp. Psychol.

B. F. Green, “Figure coherence in the kinetic depth effect,” J. Exp. Psychol. 62, 272–282 (1961).
[CrossRef] [PubMed]

J. Exp. Psychol. Human Percept. Perf.

R. Blake, N. J. Cepeda, E. Hiris, “Memory for visual motion,” J. Exp. Psychol. Human Percept. Perf. 23, 353–369 (1997).
[CrossRef]

E. Hiris, R. Blake, “Discrimination of coherent motion when local motion varies in speed and direction,” J. Exp. Psychol. Human Percept. Perf. 21, 308–317 (1995).
[CrossRef]

J. Neurophysiol.

T. D. Albright, “Direction and orientation selectivity of neurons in visual area MT of the macaque,” J. Neurophysiol. 52, 1106–1130 (1984).
[PubMed]

J. H. R. Maunsell, D. C. van Essen, “Functional properties of neurons in middle temporal visual area of the macaque monkey. I. Selectivity for stimulus direction, speed, and orientation,” J. Neurophysiol. 49, 1127–1147 (1983).
[PubMed]

J. Neurosci.

W. T. Newsome, E. B. Pare, “A selective impairment of motion perception following lesions of the middle temporal visual area (MT),” J. Neurosci. 8, 2201–2211 (1988).
[PubMed]

J. Opt. Soc. Am.

J. Opt. Soc. Am. A

Nature

D. Williams, G. Phillips, R. Sekuler, “Hysteresis in the perception of motion direction as evidence for neural cooperativity,” Nature 324, 253–255 (1986).
[CrossRef] [PubMed]

A. Grunewald, M. J. M. Lankheet, “Orthogonal motion after-effect illusion predicted by a model of cortical motion processing,” Nature 384, 358–360 (1996).
[CrossRef] [PubMed]

Percept. Psychophys.

L. T. Maloney, “Confidence intervals for the parameters of psychometric functions,” Percept. Psychophys. 47, 127–134 (1990).
[CrossRef] [PubMed]

N. Matthews, L. Welch, “Velocity-dependent improvements in single-dot direction discrimination,” Percept. Psychophys. 59, 60–72 (1997).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Masking of motion by broad-band and filtered directional noise,” Percept. Psychophys. 26, 206–214 (1979).
[CrossRef]

Perception

M. Edwards, D. Badcock, “Asymmetries in the sensitivity to motion in depth: a centripetal bias,” Perception 22, 1013–1023 (1993).
[CrossRef] [PubMed]

K. Ball, R. Sekuler, “Human vision favors centrifugal motion,” Perception 9, 317–325 (1980).
[CrossRef] [PubMed]

Proc. Natl. Acad. Sci. USA

E. Hiris, R. Blake, “Another perspective on the visual motion aftereffect,” Proc. Natl. Acad. Sci. USA 89, 9025–9028 (1992).
[CrossRef] [PubMed]

Psychol. Bull.

S. Appelle, “Perception and discrimination as a function of stimulus orientation: the oblique effect in man and animals,” Psychol. Bull. 78, 266–278 (1972).
[CrossRef] [PubMed]

Psychol. Rev.

K. Ball, R. Sekuler, “Models of stimulus uncertainty in motion perception,” Psychol. Rev. 87, 435–469 (1980).
[CrossRef] [PubMed]

Science

K. Ball, R. Sekuler, “A specific and enduring improvement in visual motion discrimination,” Science 218, 697–698 (1982).
[CrossRef] [PubMed]

W. Marshak, R. Sekuler, “Mutual repulsion between moving visual targets,” Science 205, 1399–1401 (1979).
[CrossRef] [PubMed]

R. J. W. Mansfield, “Neural basis of orientation perception in primate vision,” Science 188, 1133–1135 (1974).
[CrossRef]

B. Breitmeyer, B. Julesz, W. Kropfl, “Dynamic random-dot stereograms reveal up–down anisotropy and left–right isotropy between cortical hemifields,” Science 187, 269–270 (1975).
[CrossRef] [PubMed]

Vision Res.

E. Levinson, R. Sekuler, “A two-dimensional analysis of direction-specific adaptation,” Vision Res. 20, 103–108 (1980).
[CrossRef] [PubMed]

W. A. van de Grind, J. J. Koenderink, A. J. van Doorn, M. V. Milders, H. Voerman, “Inhomogeneity and anisotropies for motion detection in the monocular visual field of human observers,” Vision Res. 33, 1089–1107 (1993).
[CrossRef] [PubMed]

J. E. Raymond, “Directional anisotropy of motion sensitivity across the visual field,” Vision Res. 34, 1029–1038 (1994).
[CrossRef] [PubMed]

D. W. Williams, R. Sekuler, “Coherent global motion percepts from stochastic local motions,” Vision Res. 24, 55–62 (1984).
[CrossRef] [PubMed]

V. P. Ferrera, H. R. Wilson, “Perceived speed of moving two-dimensional patterns,” Vision Res. 31, 877–894 (1991).
[CrossRef] [PubMed]

J. Kim, H. R. Wilson, “Dependence of plaid motion coherence on component grating directions,” Vision Res. 33, 2479–2489 (1993);H. R. Wilson, J. Kim, “Perceived motion in the vector sum direction,” Vision Res. 34, 1835–1842 (1994).
[CrossRef] [PubMed]

B. de Bruyn, G. A. Orban, “Human velocity and direction discrimination measured with random dot patterns,” Vision Res. 28, 1323–1335 (1988).
[CrossRef]

S. N. J. Watamaniuk, R. Sekuler, D. W. Williams, “Direction perception in complex dynamic displays, the integration of direction information,” Vision Res. 29, 47–59 (1989).
[CrossRef]

M. Edwards, D. R. Badcock, “Global motion perception: interaction of the ON and OFF pathways,” Vision Res. 34, 2849–2858 (1994); R. Blake, T. S. Aiba, “Detection and discrimination of optical flow components,” Jap. Psychol. Res. 40, 19–30 (1998).
[CrossRef] [PubMed]

V. P. Ferrera, H. R. Wilson, “Perceived direction of moving two-dimensional patterns,” Vision Res. 30, 273–288 (1990).
[CrossRef] [PubMed]

D. W. Heeley, H. M. Buchanan-Smith, “Directional acuity for drifting plaids,” Vision Res. 32, 97–104 (1992).
[CrossRef] [PubMed]

N. J. Coletta, P. Segu, C. L. M. Tiana, “An oblique effect in parafoveal motion perception,” Vision Res. 33, 2747–2756 (1993).
[CrossRef] [PubMed]

D. Williams, S. Tweten, R. Sekuler, “Using metamers to explore motion perception,” Vision Res. 31, 275–286 (1991).
[CrossRef] [PubMed]

E. Levinson, R. Sekuler, “Adaptation alters perceived direction of motion,” Vision Res. 16, 779–781 (1976).
[CrossRef] [PubMed]

Visual Neurosci.

T. D. Albright, “Centrifugal directional bias in the middle temporal visual area (MT) of the macaque,” Visual Neurosci. 2, 177–188 (1989).
[CrossRef]

H. R. Wilson, V. P. Ferrera, C. Yo, “A psychophysically motivated model for two-dimensional motion perception,” Visual Neurosci. 9, 79–97 (1992).
[CrossRef]

H. R. Wilson, J. Kim, “A model for motion coherence and transparency,” Visual Neurosci. 11, 1205–1220 (1994).
[CrossRef]

K. H. Britten, M. N. Shadlen, W. T. Newsome, J. A. Movshon, “Responses of neurons in macaque MT to stochastic motion signals,” Visual Neurosci. 10, 1157–1169 (1993).
[PubMed]

E. Hiris, R. Blake, “Direction repulsion in motion transparency,” Visual Neurosci. 13, 187–197 (1996).
[PubMed]

Other

M. L. Braunstein, Depth Perception through Motion (Academic, New York, 1976).

We have not addressed models that describe the registration of Fourier motion35 and nonFourier motion,32,36 because these models focus on the design of motion sensing units and not their role in signalling direction of coherent motion. Nor do we examine models designed to account for structure from motion37 or registration of complex optic flow,38 for these models are agnostic with respect to oblique effects in motion perception.

H. R. Wilson, D. Levi, L. Maffei, J. Rovamo, R. De Valois, “The perception of form,” in Visual Perception: The Neurophysiological Foundations, L. Spillman, J. S. Werner, eds. (Academic, San Diego, Calif., 1992), pp. 231–272.

See, e.g., S. Ullman, The Interpretation of Visual Motion (MIT Press, Cambridge, Mass., 1979).

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Figures (7)

Fig. 1
Fig. 1

Experimental methods. Schematics of stimuli for experiment 1(a) and experiment 2(b). (a) Right circle, RDC with random motion (0% coherence): each dot moves in a random direction, indicated by the small arrows near each dot. Left circle, RDC containing coherent motion. A small percentage of dots in this panel move coherently in the same direction (in this case, upward), while the remaining dots move in random directions. The order of presentation is randomized, and observers must indicate which interval contains coherent motion. (b) Left circle, RDC with 50% coherence containing motion in the reference direction for the data run (in this case, upward). Right circle, RDC with motion in the test direction. On each trial observers indicated whether the test direction of motion is clockwise or counterclockwise relative to the reference direction (in this case, counterclockwise).

Fig. 2
Fig. 2

Directions of motion: the 12 directions sampled in experiment 1. The figure also shows our convention for labeling directions: 0 deg is rightward, and 90 deg is upward.

Fig. 3
Fig. 3

Experiment 1 results. The first five panels show the results for each observer, and the sixth panel shows the average results. In each polar plot the direction of motion tested is plotted as the angle and the coherence thresholds are plotted as the distance from the origin. The data show no differences in performance with direction of motion.

Fig. 4
Fig. 4

Direction discrimination example: two example psychometric functions for direction discrimination (observer LG, 50% coherence). The horizontal axis plots the angular difference between the reference and the test directions of motion, and the vertical axis specifies, in z-score units, the percentage of trials in which the observer reported clockwise for the test direction of motion. The slope of the best-fit line is steeper for the 0-deg reference direction than for the 315-deg reference direction. The difference between the angular direction values associated with 25% (z-score of -0.675) and 75% (0.675) levels of performance were taken as the measure of discrimination accuracy.

Fig. 5
Fig. 5

Experiment 2 results. The polar plots show discrimination thresholds for different reference directions; the parameter is coherence level (open circles, 25% coherence; squares, 50% coherence; and filled circles, 100% coherence). For each curve, performance is generally better for cardinal directions than for oblique directions, and the trend is seen at all three motion coherence levels.

Fig. 6
Fig. 6

Control results. Data is presented from two control conditions for observer BG. (a) Discrimination psychometric functions are shown when the observer viewed the display through a dove prism that rotated the image of the video monitor by 45 deg. Directions indicated in the legend refer to directions on the observer’s retina: rightward motion was actually down and to the right on the monitor, and oblique motion was actually rightward on the monitor. Performance was superior for the cardinal direction imaged on the retina, ruling out pixelation artifacts as an explanation for the oblique effect. (b) Direction thresholds measured with the observer’s head tilted at a 45-deg angle. The directions of motion indicated in the legend again refer to directions on the observer’s retina. Superior discrimination performance is referenced to retinal coordinates, not to gravitational coordinates.

Fig. 7
Fig. 7

Peripheral direction discrimination. Discrimination thresholds (in angular degrees) for RDC’s imaged away from foveal fixation, either 10 deg right of fixation or 10 deg down and to the right. Arrow direction indicates direction of motion around which discrimination thresholds were measured: arrow length indicates angular difference in direction at threshold. In general, performance is best for motion along cardinal directions. If centrifugal motion is in a cardinal direction (rightward for the upper trio of vectors), performance is good; if centrifugal motion is in an oblique direction (down and to the right for the lower trio of vectors), performance is poorer. Data summarize averages for two observers.

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