Speed can go up as well as down at low contrast

Implications for models of motion perception

Peter Thompson*, Kevin Brooks, Stephen T. Hammett

*Corresponding author for this work

Research output: Contribution to journalArticle

82 Citations (Scopus)


It is well-known that reducing the contrast of a slow moving stimulus reduces its apparent speed. [Thompson, P. (1982). Perceived rate of movement depends on contrast. Vision Research, 22, 377-380.] report of this finding also suggested that at speeds above 8 cycles/s reducing contrast increased perceived speed. However in a later report, Stone and Thompson (1992), using a more rigorous, forced-choice procedure, failed to collect reliable data at these higher speeds. Here, we confirm that faster moving stimuli can appear to move faster than their true speed at low contrasts and we propose a physiologically plausible ratio model that unlike recent Bayesian models (e.g. Weiss, Y., Simoncelli, E. P., & Adelson, E. H. (2002). Motion illusions as optimal percepts. Nature Neuroscience, 5, 598-604) can account well for the results.

Original languageEnglish
Pages (from-to)782-786
Number of pages5
JournalVision Research
Issue number6-7
Publication statusPublished - Mar 2006
Externally publishedYes


  • Bayesian
  • Contrast
  • Motion
  • Ratio model
  • Speed

Fingerprint Dive into the research topics of 'Speed can go up as well as down at low contrast: Implications for models of motion perception'. Together they form a unique fingerprint.

Cite this