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James A Schirillo

Publications and source records attributed to James A Schirillo.

5 recordsLinked to original sources
PubMed2005

The greater ability of graphical versus numerical displays to increase risk avoidance involves a common mechanism.

By displaying a risk reduction of 50% graphically rather than numerically, Stone, Yates, and Parker significantly increased professed risk-avoidant behavior. The current experiments replicated this effect at various risk ratios. Specifically, participants were willing to spend more money to reduce a risk when the risk information was displayed by asterisks rather than by numbers for risk-reduction ratios ranging from 3% to 97%. Transforming the amount participants were willing to spend to logarithms significantly improved a linear fit to the data, suggesting that participants convert this variable within the decision-making process. Moreover, a log-linear model affords an exceptional fit to both the graphical and numerical data, suggesting that a graphical presentation elicits the same decision-making mechanism as does the numerical display. In addition, the data also suggest that each person removed from harm is weighted more by some additional factor in the graphical compared to the numerical presentations.

Journal Article↗
PubMed2005

Chromatic shadow compatibility and cone-excitation ratios.

Logvinenko [Perception 31, 201 (2002)] asserts that Adelson's wall-of-blocks illusion [Science 262, 2042 (1993)], where identical gray-cube surface tops appear to differ in brightness, arises when the surfaces surrounding the cube tops are shadow compatible, creating a concomitant illusion of transparency. We replicated Logvinenko's main findings in the chromatic domain across three experiments in which observers match cube tops in hue, saturation, and brightness. A second set of stimuli adjusted cone-excitation ratios across the apparent transparency border [Proc. R. Soc. London 257, 115 (1994)], which enhanced lightness and brightness constancy but only when the stimuli varied in both chromaticity and intensity.

Adult↗
PubMed2003

Three-dimensional spatial grouping affects estimates of the illuminant.

The brightnesses (i.e., perceived luminance) of surfaces within a three-dimensional scene are contingent on both the luminances and the spatial arrangement of the surfaces. Observers viewed a CRT through a haploscope that presented simulated achromatic surfaces in three dimensions. They set a test patch to be approximately 33% more intense than a comparison patch to match the comparison patch in brightness, which is consistent with viewing a real scene with a simple lightning interpretation from which to estimate a different level of illumination in each depth plane. Randomly positioning each surface in either depth plane minimized any simple lighting interpretation, concomitantly reducing brightness differences to approximately 8.5%, although the immediate surrounds of the test and comparison patches continued to differ by a 5:1 luminance ratio.

Adult↗
PubMed2002

Articulation: brightness, apparent illumination, and contrast ratios.

Luminance edges in the environment can be due to regions that differ in reflectance or in illumination. In three experiments, we varied the spatial organization of 10 achromatic (simulated) surfaces so that some arrangements were consistent with an ecologically valid and parsimonious interpretation of 5 surfaces under two different illuminants. A constant contrast-ratio along a luminance edge in the scene allows this interpretation. The brightness of patches in this condition was compared to their brightness with minimally different spatial arrangements that fail to maintain the constant contrast-ratio criterion. When the spatial arrangement of the 10 surfaces included a luminance edge satisfying the constant contrast-ratio criterion, brightness changed systematically, compared to arrangements without such a luminance edge. We account for the results by positing that a luminance edge with a constant contrast-ratio segments the scene into regions of lower and higher illumination, with the same effect as a difference in real physical illumination: all else equal, a given surface appears brighter under higher than under lower illumination.

Adult↗