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ERIC Number: EJ823683
Record Type: Journal
Publication Date: 2008-Oct
Pages: 3
Abstractor: As Provided
Reference Count: 0
ISSN: ISSN-0033-295X
Postscript: Qualifying and Quantifying Constraints on Perceived Transparency
Anderson, Barton L.; Singh, Manish; O'Vari, Judit
Psychological Review, v115 n4 p1151-1153 Oct 2008
Contrary to Albert's claims, the results of previous studies do not favor a perceived contrast model over a ratio-of-perceived-contrasts model (see Points 1-3 below and our main response). Realizing that a simple perceived contrast model leads to predictions that violate "common sense," Albert postulated a division of the continuous dimension of perceived opacity into a small number of distinct qualitative regimes of transparency, arguing that subjects will only match opacity within the same regime. Questions of parsimony aside, critical issues concerning how the model actually works are left unaddressed: How does the visual system decide to which qualitative regime a display belongs (e.g., highly transparent vs. medium transparent)? Albert simply listed filter-to-background relative properties (which we have previously articulated as being crucial, including ratio-of-perceived contrast) without specifying how such variables determine the categories of filters he proposed. According to his model, a subject would first adjust the match display so the two filters are in the same qualitative regime and would then match perceived contrast. However, once the two filters have been brought into the same regime, there is no guarantee that a perceived contrast match will be available (especially if the two display backgrounds differ strongly in contrast). It is completely unspecified what his model predicts in such conditions. In sum, Albert's arguments fail because the ratio-of-perceived contrast model can only be assessed with experiments in which perceived transmittance and perceived contrast are measured using the same match pattern and mapped onto a common scale, something that is missing in both Albert's experiments and the data he attempted to levy against our model from other articles.
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Publication Type: Journal Articles; Opinion Papers; Reports - Descriptive
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A