Purchase this article with an account.
Takehiro Nagai, Hiroto Kimura, Shigeki Nakauchi; Sensitivity impairment for detecting color alternation along an apparent motion trajectory. Journal of Vision 2011;11(11):744. doi: 10.1167/11.11.744.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Introduction: Beer et al. (VSS 2007) has reported that luminance modulation on multiple targets was perceptually underestimated when they were perceived as a single moving object (apparent motion). This phenomenon supports the idea that brightness signals are integrated along a motion trajectory. If this is the case similar effects may be also observed for color domain. Here we investigated whether color modulation detectability is impaired on apparent motion stimuli, and whether this impairment is surely attributed to motion perception. Methods: The stimuli were discs sequentially presented at concyclic eight locations with large spatial gaps (6.1 deg), and disc colors alternate between two colors on the L-M direction. There were two parameters to control strength of motion perception for the stimuli: stimulus onset asynchrony (SOA) and background color. The SOA changes strength of apparent motion perception (intermediate SOAs yield the strongest perception). For background color we had two conditions: the black condition, where the background color was black, and the isoluminance condition, where purple isoluminant with disc colors. Therefore motion perception was stronger for the black condition than the isoluminance condition. Color difference thresholds to detect the color alternations were measured using a 2IFC task. Results and Discussions: For the isoluminance condition, the measured sensitivity monotonically decreases as the SOA increases, as simply expected from need for iconic memory for long SOAs. By contrast, for the black condition the sensitivity was the lowest in the intermediate SOA yielding the strongest motion perception than in the other SOAs. Namely, sensitivity for detecting color modulation was impaired when motion perception was strong. These results are consistent with the idea that color signals, not only brightness signals, are integrated along an apparent motion path even when the stimulus has large spatial gaps between elements that prevent color integration in small receptive fields.
This PDF is available to Subscribers Only