Abstract

Thresholds were assessed for a speed discrimination task with a pair of luminance-defined drifting gratings. The design and results of a series of experiments dealing in general with speed discrimination are described. Results show that for a speed discrimination task using drifting gratings, simultaneous presentation of the pair of gratings (spatially separated) was preferred over sequential presentation (temporally separated) in order to minimize the effects of eye movements and tracking. An interstimulus interval of at least 1000ms was necessary to prevent motion aftereffects on subsequently viewed stimuli. For the two reference speeds tested of 2 and 8degs using identical spatial frequency or randomizing spatial frequency for the pair of gratings did not affect speed discrimination thresholds. Implementing a staircase method of estimating thresholds was preferred over the method of constant stimuli or the method of limits. The results of these experiments were used to define the methodology for an investigation of aging and motion perception. These results will be of interest and use to psychophysicists designing and implementing speed discrimination paradigms.

© 2005 Optical Society of America

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  1. A. G. Goldstein, “Judgments of visual velocity as a function of length of observation time,” J. Exp. Psychol. 54, 457–461 (1957).
    [CrossRef] [PubMed]
  2. V. R. Carlson, “Adaptation in the perception of visual velocity,” J. Exp. Psychol. 64, 192–197 (1962).
    [CrossRef] [PubMed]
  3. F. W. Campbell, L. Maffei, “The influence of spatial frequency and contrast on the perception of moving patterns,” Vision Res. 21, 713–21 (1981).
    [CrossRef] [PubMed]
  4. S. P. McKee, “A local mechanism for differential velocity detection,” Vision Res. 21, 491–500 (1981).
    [CrossRef] [PubMed]
  5. S. P. McKee, G. H. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
    [CrossRef] [PubMed]
  6. G. A. Orban, J. S. deWolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
    [CrossRef] [PubMed]
  7. G. A. Orban, F. Van Calenbergh, D. deBryuyn, H. Maes, “Velocity discrimination in central and peripheral visual field,” J. Opt. Soc. Am. A 2, 1836–1847 (1985).
    [CrossRef] [PubMed]
  8. B. Brown, K. Bowman, “Sensitivity to changes in size and velocity in young and elderly observers,” Perception 16, 41–47 (1987).
    [CrossRef] [PubMed]
  9. H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
    [CrossRef] [PubMed]
  10. A. T. Smith, G. K. Edgar, “The influence of spatial frequency on perceived temporal frequency and speed,” Vision Res. 30, 1467–1474 (1990).
    [CrossRef]
  11. M. R. Blakemore, R. J. Snowden, “The effect of contrast upon perceived speed: a general phenomenon?” Perception 28, 33–48 (1999).
    [CrossRef]
  12. C. W. G. Clifford, P. Wenderoth, “Adaptation to temporal modulation can enhance differential speed sensitivity,” Vision Res. 39, 4324–4332 (1999).
    [CrossRef]
  13. A. Johnston, C. P. Benton, M. J. Morgan, “Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli,” Vision Res. 39, 3849–3854 (1999).
    [CrossRef]
  14. R. Muller, M. W. Greenlee, “Effect of contrast and adaptation on the perception of direction and speed of drifting gratings,” Vision Res. 34, 2071–2092 (1994).
    [CrossRef]
  15. P. Thompson, “Discrimination of moving gratings at and above detection threshold,” Vision Res. 23, 1533–1538 (1983).
    [CrossRef] [PubMed]
  16. A. T. Smith, “Velocity perception and discrimination: Relation to temporal mechanism,” Vision Res. 27, 1494–1500 (1987).
    [CrossRef]
  17. A. J. Pantle, “Temporal frequency response characteristic of motion channels measured with three different psychophysical techniques,” Percept. Psychophys. 24, 285–294 (1978).
    [CrossRef] [PubMed]
  18. B. Moulden, J. Renshaw, G. Mather, “Two channels for flicker in the human visual system,” Perception 13, 387–400 (1984).
    [CrossRef] [PubMed]
  19. S. J. Anderson, D. C. Burr, “Spatial and temporal selectivity of the human motion detection system,” Vision Res. 25, 1147–1154 (1985).
    [CrossRef] [PubMed]
  20. M. B. Mandler, W. Makous, “A three channel model of temporal frequency perception,” Vision Res. 24, 1881–1887 (1984).
    [CrossRef] [PubMed]
  21. P. Thompson, “The coding of velocity of movement in the human visual system,” Vision Res. 24, 41–45 (1984).
    [CrossRef] [PubMed]
  22. R. F. Hess, G. T. Plant, “Temporal frequency discrimination in human vision: Evidence for an additional mechanism in the low spatial and high temporal region,” Vision Res. 25, 1493–1500 (1985).
    [CrossRef]
  23. M. G. Harris, “The perception of moving stimuli: A model of spatiotemporal coding in human vision,” Vision Res. 26, 1281–1287 (1986).
    [CrossRef] [PubMed]
  24. G. A. Gescheider, Psychophysics: The Fundamentals. (Erlbaum, 1997).
  25. K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
    [CrossRef] [PubMed]
  26. B. de Bruyn, G. A. Orban, “Human velocity and direction discrimination measured with random dot patterns,” Vision Res. 28, 1323–1335 (1988).
    [CrossRef] [PubMed]
  27. S. N. J. Watamaniuk, A. Duchon, “The human visual system averages speed information,” Vision Res. 32, 931–941 (1992).
    [CrossRef] [PubMed]
  28. P. Verghese, L. S. Stone, “Spatial layout affects speed discrimination,” Vision Res. 37, 397–406 (1997).
    [CrossRef] [PubMed]
  29. P. Thompson, “Perceived rate of movement depends on contrast,” Vision Res. 22, 377–380 (1982).
    [CrossRef] [PubMed]
  30. A. Raghuram, V. Lakshminarayanan, “Effect of inter stimulus interval on speed discrimination,” presented at Frontiers in Optics/Laser Science XIX, Optical Society of America Annual Meeting, Tucson, October 5–9, 2003 Arizona MT 24.
  31. A. Raghuram, V. Lakshminarayanan, R. Khanna, “Psychophysical estimation of speed discrimination. II.  Aging effects,” J. Opt. Soc. Am. A 22, 2269–2280 (2005).
    [CrossRef]

2005

1999

M. R. Blakemore, R. J. Snowden, “The effect of contrast upon perceived speed: a general phenomenon?” Perception 28, 33–48 (1999).
[CrossRef]

C. W. G. Clifford, P. Wenderoth, “Adaptation to temporal modulation can enhance differential speed sensitivity,” Vision Res. 39, 4324–4332 (1999).
[CrossRef]

A. Johnston, C. P. Benton, M. J. Morgan, “Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli,” Vision Res. 39, 3849–3854 (1999).
[CrossRef]

1997

P. Verghese, L. S. Stone, “Spatial layout affects speed discrimination,” Vision Res. 37, 397–406 (1997).
[CrossRef] [PubMed]

1994

R. Muller, M. W. Greenlee, “Effect of contrast and adaptation on the perception of direction and speed of drifting gratings,” Vision Res. 34, 2071–2092 (1994).
[CrossRef]

1992

S. N. J. Watamaniuk, A. Duchon, “The human visual system averages speed information,” Vision Res. 32, 931–941 (1992).
[CrossRef] [PubMed]

1990

A. T. Smith, G. K. Edgar, “The influence of spatial frequency on perceived temporal frequency and speed,” Vision Res. 30, 1467–1474 (1990).
[CrossRef]

1989

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

1988

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

1987

A. T. Smith, “Velocity perception and discrimination: Relation to temporal mechanism,” Vision Res. 27, 1494–1500 (1987).
[CrossRef]

B. Brown, K. Bowman, “Sensitivity to changes in size and velocity in young and elderly observers,” Perception 16, 41–47 (1987).
[CrossRef] [PubMed]

1986

S. P. McKee, G. H. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

M. G. Harris, “The perception of moving stimuli: A model of spatiotemporal coding in human vision,” Vision Res. 26, 1281–1287 (1986).
[CrossRef] [PubMed]

1985

S. J. Anderson, D. C. Burr, “Spatial and temporal selectivity of the human motion detection system,” Vision Res. 25, 1147–1154 (1985).
[CrossRef] [PubMed]

R. F. Hess, G. T. Plant, “Temporal frequency discrimination in human vision: Evidence for an additional mechanism in the low spatial and high temporal region,” Vision Res. 25, 1493–1500 (1985).
[CrossRef]

G. A. Orban, F. Van Calenbergh, D. deBryuyn, H. Maes, “Velocity discrimination in central and peripheral visual field,” J. Opt. Soc. Am. A 2, 1836–1847 (1985).
[CrossRef] [PubMed]

1984

G. A. Orban, J. S. deWolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

B. Moulden, J. Renshaw, G. Mather, “Two channels for flicker in the human visual system,” Perception 13, 387–400 (1984).
[CrossRef] [PubMed]

M. B. Mandler, W. Makous, “A three channel model of temporal frequency perception,” Vision Res. 24, 1881–1887 (1984).
[CrossRef] [PubMed]

P. Thompson, “The coding of velocity of movement in the human visual system,” Vision Res. 24, 41–45 (1984).
[CrossRef] [PubMed]

1983

P. Thompson, “Discrimination of moving gratings at and above detection threshold,” Vision Res. 23, 1533–1538 (1983).
[CrossRef] [PubMed]

1982

P. Thompson, “Perceived rate of movement depends on contrast,” Vision Res. 22, 377–380 (1982).
[CrossRef] [PubMed]

1981

F. W. Campbell, L. Maffei, “The influence of spatial frequency and contrast on the perception of moving patterns,” Vision Res. 21, 713–21 (1981).
[CrossRef] [PubMed]

S. P. McKee, “A local mechanism for differential velocity detection,” Vision Res. 21, 491–500 (1981).
[CrossRef] [PubMed]

1978

A. J. Pantle, “Temporal frequency response characteristic of motion channels measured with three different psychophysical techniques,” Percept. Psychophys. 24, 285–294 (1978).
[CrossRef] [PubMed]

1976

H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
[CrossRef] [PubMed]

1962

V. R. Carlson, “Adaptation in the perception of visual velocity,” J. Exp. Psychol. 64, 192–197 (1962).
[CrossRef] [PubMed]

1957

A. G. Goldstein, “Judgments of visual velocity as a function of length of observation time,” J. Exp. Psychol. 54, 457–461 (1957).
[CrossRef] [PubMed]

Anderson, S. J.

S. J. Anderson, D. C. Burr, “Spatial and temporal selectivity of the human motion detection system,” Vision Res. 25, 1147–1154 (1985).
[CrossRef] [PubMed]

Benton, C. P.

A. Johnston, C. P. Benton, M. J. Morgan, “Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli,” Vision Res. 39, 3849–3854 (1999).
[CrossRef]

Blakemore, M. R.

M. R. Blakemore, R. J. Snowden, “The effect of contrast upon perceived speed: a general phenomenon?” Perception 28, 33–48 (1999).
[CrossRef]

Bowman, K.

B. Brown, K. Bowman, “Sensitivity to changes in size and velocity in young and elderly observers,” Perception 16, 41–47 (1987).
[CrossRef] [PubMed]

Brandt, T. H.

H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
[CrossRef] [PubMed]

Brown, B.

B. Brown, K. Bowman, “Sensitivity to changes in size and velocity in young and elderly observers,” Perception 16, 41–47 (1987).
[CrossRef] [PubMed]

Burr, D. C.

S. J. Anderson, D. C. Burr, “Spatial and temporal selectivity of the human motion detection system,” Vision Res. 25, 1147–1154 (1985).
[CrossRef] [PubMed]

Campbell, F. W.

F. W. Campbell, L. Maffei, “The influence of spatial frequency and contrast on the perception of moving patterns,” Vision Res. 21, 713–21 (1981).
[CrossRef] [PubMed]

Carlson, V. R.

V. R. Carlson, “Adaptation in the perception of visual velocity,” J. Exp. Psychol. 64, 192–197 (1962).
[CrossRef] [PubMed]

Clifford, C. W. G.

C. W. G. Clifford, P. Wenderoth, “Adaptation to temporal modulation can enhance differential speed sensitivity,” Vision Res. 39, 4324–4332 (1999).
[CrossRef]

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] [PubMed]

deBryuyn, D.

deWolf, J. S.

G. A. Orban, J. S. deWolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

Dichgans, J.

H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
[CrossRef] [PubMed]

Diener, H. C.

H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
[CrossRef] [PubMed]

Duchon, A.

S. N. J. Watamaniuk, A. Duchon, “The human visual system averages speed information,” Vision Res. 32, 931–941 (1992).
[CrossRef] [PubMed]

Edgar, G. K.

A. T. Smith, G. K. Edgar, “The influence of spatial frequency on perceived temporal frequency and speed,” Vision Res. 30, 1467–1474 (1990).
[CrossRef]

Gescheider, G. A.

G. A. Gescheider, Psychophysics: The Fundamentals. (Erlbaum, 1997).

Goldstein, A. G.

A. G. Goldstein, “Judgments of visual velocity as a function of length of observation time,” J. Exp. Psychol. 54, 457–461 (1957).
[CrossRef] [PubMed]

Greenlee, M. W.

R. Muller, M. W. Greenlee, “Effect of contrast and adaptation on the perception of direction and speed of drifting gratings,” Vision Res. 34, 2071–2092 (1994).
[CrossRef]

Harris, M. G.

M. G. Harris, “The perception of moving stimuli: A model of spatiotemporal coding in human vision,” Vision Res. 26, 1281–1287 (1986).
[CrossRef] [PubMed]

Hess, R. F.

R. F. Hess, G. T. Plant, “Temporal frequency discrimination in human vision: Evidence for an additional mechanism in the low spatial and high temporal region,” Vision Res. 25, 1493–1500 (1985).
[CrossRef]

Johnston, A.

A. Johnston, C. P. Benton, M. J. Morgan, “Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli,” Vision Res. 39, 3849–3854 (1999).
[CrossRef]

Khanna, R.

Lakshminarayanan, V.

A. Raghuram, V. Lakshminarayanan, R. Khanna, “Psychophysical estimation of speed discrimination. II.  Aging effects,” J. Opt. Soc. Am. A 22, 2269–2280 (2005).
[CrossRef]

A. Raghuram, V. Lakshminarayanan, “Effect of inter stimulus interval on speed discrimination,” presented at Frontiers in Optics/Laser Science XIX, Optical Society of America Annual Meeting, Tucson, October 5–9, 2003 Arizona MT 24.

Maes, H.

G. A. Orban, F. Van Calenbergh, D. deBryuyn, H. Maes, “Velocity discrimination in central and peripheral visual field,” J. Opt. Soc. Am. A 2, 1836–1847 (1985).
[CrossRef] [PubMed]

G. A. Orban, J. S. deWolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

Maffei, L.

F. W. Campbell, L. Maffei, “The influence of spatial frequency and contrast on the perception of moving patterns,” Vision Res. 21, 713–21 (1981).
[CrossRef] [PubMed]

Makous, W.

M. B. Mandler, W. Makous, “A three channel model of temporal frequency perception,” Vision Res. 24, 1881–1887 (1984).
[CrossRef] [PubMed]

Mandler, M. B.

M. B. Mandler, W. Makous, “A three channel model of temporal frequency perception,” Vision Res. 24, 1881–1887 (1984).
[CrossRef] [PubMed]

Mather, G.

B. Moulden, J. Renshaw, G. Mather, “Two channels for flicker in the human visual system,” Perception 13, 387–400 (1984).
[CrossRef] [PubMed]

McKee, S. P.

S. P. McKee, G. H. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

S. P. McKee, “A local mechanism for differential velocity detection,” Vision Res. 21, 491–500 (1981).
[CrossRef] [PubMed]

Morgan, M. J.

A. Johnston, C. P. Benton, M. J. Morgan, “Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli,” Vision Res. 39, 3849–3854 (1999).
[CrossRef]

Moulden, B.

B. Moulden, J. Renshaw, G. Mather, “Two channels for flicker in the human visual system,” Perception 13, 387–400 (1984).
[CrossRef] [PubMed]

Muller, R.

R. Muller, M. W. Greenlee, “Effect of contrast and adaptation on the perception of direction and speed of drifting gratings,” Vision Res. 34, 2071–2092 (1994).
[CrossRef]

Nakayama, K.

S. P. McKee, G. H. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [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] [PubMed]

G. A. Orban, F. Van Calenbergh, D. deBryuyn, H. Maes, “Velocity discrimination in central and peripheral visual field,” J. Opt. Soc. Am. A 2, 1836–1847 (1985).
[CrossRef] [PubMed]

G. A. Orban, J. S. deWolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

Pantle, A.

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

Pantle, A. J.

A. J. Pantle, “Temporal frequency response characteristic of motion channels measured with three different psychophysical techniques,” Percept. Psychophys. 24, 285–294 (1978).
[CrossRef] [PubMed]

Plant, G. T.

R. F. Hess, G. T. Plant, “Temporal frequency discrimination in human vision: Evidence for an additional mechanism in the low spatial and high temporal region,” Vision Res. 25, 1493–1500 (1985).
[CrossRef]

Raghuram, A.

A. Raghuram, V. Lakshminarayanan, R. Khanna, “Psychophysical estimation of speed discrimination. II.  Aging effects,” J. Opt. Soc. Am. A 22, 2269–2280 (2005).
[CrossRef]

A. Raghuram, V. Lakshminarayanan, “Effect of inter stimulus interval on speed discrimination,” presented at Frontiers in Optics/Laser Science XIX, Optical Society of America Annual Meeting, Tucson, October 5–9, 2003 Arizona MT 24.

Renshaw, J.

B. Moulden, J. Renshaw, G. Mather, “Two channels for flicker in the human visual system,” Perception 13, 387–400 (1984).
[CrossRef] [PubMed]

Silverman, G. H.

S. P. McKee, G. H. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

Smith, A. T.

A. T. Smith, G. K. Edgar, “The influence of spatial frequency on perceived temporal frequency and speed,” Vision Res. 30, 1467–1474 (1990).
[CrossRef]

A. T. Smith, “Velocity perception and discrimination: Relation to temporal mechanism,” Vision Res. 27, 1494–1500 (1987).
[CrossRef]

Snowden, R. J.

M. R. Blakemore, R. J. Snowden, “The effect of contrast upon perceived speed: a general phenomenon?” Perception 28, 33–48 (1999).
[CrossRef]

Stone, L. S.

P. Verghese, L. S. Stone, “Spatial layout affects speed discrimination,” Vision Res. 37, 397–406 (1997).
[CrossRef] [PubMed]

Thompson, P.

P. Thompson, “The coding of velocity of movement in the human visual system,” Vision Res. 24, 41–45 (1984).
[CrossRef] [PubMed]

P. Thompson, “Discrimination of moving gratings at and above detection threshold,” Vision Res. 23, 1533–1538 (1983).
[CrossRef] [PubMed]

P. Thompson, “Perceived rate of movement depends on contrast,” Vision Res. 22, 377–380 (1982).
[CrossRef] [PubMed]

Turano, K.

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[CrossRef] [PubMed]

Van Calenbergh, F.

Verghese, P.

P. Verghese, L. S. Stone, “Spatial layout affects speed discrimination,” Vision Res. 37, 397–406 (1997).
[CrossRef] [PubMed]

Watamaniuk, S. N. J.

S. N. J. Watamaniuk, A. Duchon, “The human visual system averages speed information,” Vision Res. 32, 931–941 (1992).
[CrossRef] [PubMed]

Wenderoth, P.

C. W. G. Clifford, P. Wenderoth, “Adaptation to temporal modulation can enhance differential speed sensitivity,” Vision Res. 39, 4324–4332 (1999).
[CrossRef]

Wist, E. R.

H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
[CrossRef] [PubMed]

J. Exp. Psychol.

A. G. Goldstein, “Judgments of visual velocity as a function of length of observation time,” J. Exp. Psychol. 54, 457–461 (1957).
[CrossRef] [PubMed]

V. R. Carlson, “Adaptation in the perception of visual velocity,” J. Exp. Psychol. 64, 192–197 (1962).
[CrossRef] [PubMed]

J. Opt. Soc. Am. A

Percept. Psychophys.

A. J. Pantle, “Temporal frequency response characteristic of motion channels measured with three different psychophysical techniques,” Percept. Psychophys. 24, 285–294 (1978).
[CrossRef] [PubMed]

Perception

B. Moulden, J. Renshaw, G. Mather, “Two channels for flicker in the human visual system,” Perception 13, 387–400 (1984).
[CrossRef] [PubMed]

B. Brown, K. Bowman, “Sensitivity to changes in size and velocity in young and elderly observers,” Perception 16, 41–47 (1987).
[CrossRef] [PubMed]

M. R. Blakemore, R. J. Snowden, “The effect of contrast upon perceived speed: a general phenomenon?” Perception 28, 33–48 (1999).
[CrossRef]

Vision Res.

C. W. G. Clifford, P. Wenderoth, “Adaptation to temporal modulation can enhance differential speed sensitivity,” Vision Res. 39, 4324–4332 (1999).
[CrossRef]

A. Johnston, C. P. Benton, M. J. Morgan, “Concurrent measurement of perceived speed and speed discrimination threshold using the method of single stimuli,” Vision Res. 39, 3849–3854 (1999).
[CrossRef]

R. Muller, M. W. Greenlee, “Effect of contrast and adaptation on the perception of direction and speed of drifting gratings,” Vision Res. 34, 2071–2092 (1994).
[CrossRef]

P. Thompson, “Discrimination of moving gratings at and above detection threshold,” Vision Res. 23, 1533–1538 (1983).
[CrossRef] [PubMed]

A. T. Smith, “Velocity perception and discrimination: Relation to temporal mechanism,” Vision Res. 27, 1494–1500 (1987).
[CrossRef]

K. Turano, A. Pantle, “On the mechanism that encodes the movement of contrast variations: velocity discrimination,” Vision Res. 29, 207–221 (1989).
[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] [PubMed]

S. N. J. Watamaniuk, A. Duchon, “The human visual system averages speed information,” Vision Res. 32, 931–941 (1992).
[CrossRef] [PubMed]

P. Verghese, L. S. Stone, “Spatial layout affects speed discrimination,” Vision Res. 37, 397–406 (1997).
[CrossRef] [PubMed]

P. Thompson, “Perceived rate of movement depends on contrast,” Vision Res. 22, 377–380 (1982).
[CrossRef] [PubMed]

H. C. Diener, E. R. Wist, J. Dichgans, T. H. Brandt, “The spatial frequency effect on perceived velocity,” Vision Res. 16, 169–176 (1976).
[CrossRef] [PubMed]

A. T. Smith, G. K. Edgar, “The influence of spatial frequency on perceived temporal frequency and speed,” Vision Res. 30, 1467–1474 (1990).
[CrossRef]

F. W. Campbell, L. Maffei, “The influence of spatial frequency and contrast on the perception of moving patterns,” Vision Res. 21, 713–21 (1981).
[CrossRef] [PubMed]

S. P. McKee, “A local mechanism for differential velocity detection,” Vision Res. 21, 491–500 (1981).
[CrossRef] [PubMed]

S. P. McKee, G. H. Silverman, K. Nakayama, “Precise velocity discrimination despite random variations in temporal frequency and contrast,” Vision Res. 26, 609–619 (1986).
[CrossRef] [PubMed]

G. A. Orban, J. S. deWolf, H. Maes, “Factors influencing velocity coding in the human visual system,” Vision Res. 24, 33–39 (1984).
[CrossRef] [PubMed]

S. J. Anderson, D. C. Burr, “Spatial and temporal selectivity of the human motion detection system,” Vision Res. 25, 1147–1154 (1985).
[CrossRef] [PubMed]

M. B. Mandler, W. Makous, “A three channel model of temporal frequency perception,” Vision Res. 24, 1881–1887 (1984).
[CrossRef] [PubMed]

P. Thompson, “The coding of velocity of movement in the human visual system,” Vision Res. 24, 41–45 (1984).
[CrossRef] [PubMed]

R. F. Hess, G. T. Plant, “Temporal frequency discrimination in human vision: Evidence for an additional mechanism in the low spatial and high temporal region,” Vision Res. 25, 1493–1500 (1985).
[CrossRef]

M. G. Harris, “The perception of moving stimuli: A model of spatiotemporal coding in human vision,” Vision Res. 26, 1281–1287 (1986).
[CrossRef] [PubMed]

Other

G. A. Gescheider, Psychophysics: The Fundamentals. (Erlbaum, 1997).

A. Raghuram, V. Lakshminarayanan, “Effect of inter stimulus interval on speed discrimination,” presented at Frontiers in Optics/Laser Science XIX, Optical Society of America Annual Meeting, Tucson, October 5–9, 2003 Arizona MT 24.

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Figures (4)

Fig. 1
Fig. 1

Differences observed in the speed discrimination task for the different psychophysical methods (standard speed, 2 deg s ). Error bars denote ± standard error.

Fig. 2
Fig. 2

Comparison between simultaneous and sequential presentation mode on speed discrimination task. Upper plots, standard speed 2 deg s . Lower plots, standard speed 8 deg s . At 500 ms stimulus duration, sequential mode had better threshold than simultaneous for both standard speeds tested. No significant difference in threshold was observed between the two presentation modes at 1000 ms stimulus duration.

Fig. 3
Fig. 3

Speed discrimination threshold plotted for constant or randomized (20%) spatial frequency of drifting gratings. Standard speed, 2 deg s or 8 deg s . Spatial frequency, 2   cycles deg . Significant differences were not observed for speed discrimination threshold between identical and randomized spatial frequency condition.

Fig. 4
Fig. 4

Weber fractions for speed discrimination plotted as a function of ISI for standard speed of 4 deg s (triangles) and 8 deg s (circles). Thresholds for an ISI of 250 to 500 ms are significantly different from those for 1000 ms and above.

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