Purchase this article with an account.
Sara Adams, Daw-An Wu, Shinsuke Shimojo; Dynamic vision in the extreme-periphery: Perception of flicker rate. Journal of Vision 2020;20(11):1714. doi: https://doi.org/10.1167/jov.20.11.1714.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previously, we reported that flickering stimuli appeared to flicker more rapidly when viewed in the extreme periphery (Shimojo et. al. VSS 2019). Here, we explore this effect in more quantitative detail.
Two back-projection screens stood at a 90˚ angle, forming a panoramic display. A single ProPixx projector cast its video across both screens with a 1440 Hz refresh rate. Typical stimuli were a pair of disks (2-4˚), with one presented at the fovea and the other in the periphery (15-90˚). Flicker frequencies ranged from 2-15 Hz. Observers performed a variety of tasks: simultaneous matching by adjusting rate of foveal or peripheral stimulus, reproduction from memory, or categorical response (faster/slower).
Observers’ subjective reports and task responses revealed large attention and memory effects: during matching tasks, the perceived rate seemed to fluctuate as attention shifted between observing the reference stimulus and adjusting the test stimulus. Reproduction from memory showed large anchoring effects—participants had difficulty remembering the reference rate while manipulating the test stimulus. Categorical reports on simultaneously presented stimuli were more stable, providing psychometric functions for stimuli presented at different rates and eccentricities.
So far, we have seen the strongest effects for flickers ranging from 5-13 Hz. The effect of eccentricity varied depending on frequency. At the upper end of frequencies, the effect remained level across a wide range of eccentricities. At the lower end, the effect increased as eccentricity increased.
This effect of eccentricity was somewhat greater when presenting disks alternating between black and white on a gray background, as opposed to white disks flashing upon a black background. The gray background stimulus also induced an action capture effect (see Wu et al, VSS 2020).
Further experiments will explore more parameter space, other types of feature changes, cross-modal interactions, and neural correlates in EEG spectra.
This PDF is available to Subscribers Only