Simultaneous brightness contrast as a function of repeated trials

Simultaneous brightness contrast of foraging Papilio butterflies.

This study focuses on the sense of brightness in the foraging Japanese yellow swallowtail butterfly, Papilio xuthus. We presented two red discs of different intensity on a grey background to butterflies, and trained them to select one of the discs. They were successfully trained to select either a high intensity or a low intensity disc. The trained butterflies were tested on their ability to pe...

Simultaneous brightness contrast for flashes of light of different durations.

Measurements have been made of the magnitude of simultaneous brightness contrast on two young adult male observers by a binocular brightness matching method. Five different luminances of the inducing pattern were studied and the duration of the exposure was varied between 5 and 150 msec, along an arithmetic scale. For low inducing flash luminances, the longer exposures show the greater contrast...

Brightness as a function of retinal locus

Brightness functions were determined for the dark-adapted fovea and periphery. In one series of experiments, observers matched numbers to the brightness of a 1° white target at various intensities, presented half the time to the fovea, the other half to one of five peripheral loci: 5°, 12°, 20°, 35°, and (;0°. In a second series, observers matched the brightness of a 1°white target in the fovea...

Similar mechanisms underlie simultaneous brightness contrast and grating induction

The experiments explore whether the mechanism(s) underlying grating induction (GI) can also account for simultaneous brightness contrast (SBC). At each of three test field heights (1, 3 and 6 deg), point-by-point brightness matches were obtained from two subjects for test field widths of 32 deg (GI condition), 14, 12, 8, 6, 3 and 1 deg. The point-by-point brightness matches were quantitatively ...

Visual detection probability of "sonar" targets as a function of retinal position and brightness contrast.