An empirical explanation of the flash-lag effect.

Journal Article (Journal Article)

When a flash of light is presented in physical alignment with a moving object, the flash is perceived to lag behind the position of the object. This phenomenon, known as the flash-lag effect, has been of particular interest to vision scientists because of the challenge it presents to understanding how the visual system generates perceptions of objects in motion. Although various explanations have been offered, the significance of this effect remains a matter of debate. Here, we show that: (i) contrary to previous reports based on limited data, the flash-lag effect is an increasing nonlinear function of image speed; and (ii) this function is accurately predicted by the frequency of occurrence of image speeds generated by the perspective transformation of moving objects. These results support the conclusion that perceptions of the relative position of a moving object are determined by accumulated experience with image speeds, in this way allowing for visual behavior in response to real-world sources whose speeds and positions cannot be perceived directly.

Full Text

Duke Authors

Cited Authors

  • Wojtach, WT; Sung, K; Truong, S; Purves, D

Published Date

  • October 13, 2008

Published In

Volume / Issue

  • 105 / 42

Start / End Page

  • 16338 - 16343

PubMed ID

  • 18852459

Pubmed Central ID

  • PMC2566991

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.0808916105


  • eng