Kimberly A. Jameson - US grants

The relations between cognitive salience and color lexicons have been widely studied and yet results from existing research in this area are either lacking in explanatory scope or are methodologically unsound. The proposed research aims to fill a gap in the area and answer important questions for the general study of cognition and semantics. It is argued that the proposed work belongs to a larger class of research problems involving general issues of cognitive structure and category membership, and that the work also bears upon important practical applications. The proposed research will investigate relationships between color- semantics and cognitive salience by targeting four specific goals: (l) provide numerical mappings of color-appearance space that quantitatively define the cognitive mappings of 'best exemplars' for tested lexical labels. (2) determine if the mappings of exemplar regions vary across genders and across samples of tested populations. (3) determine the invariance properties (for both changes in paradigm and context) of these 'best exemplar' regions thereby providing a test of the validity of generalizing color-naming results from relatively simple viewing circumstances to situations that are contextually richer. And, (4) using unusually stringent methods, develop a base of normative empirical results that will serve as a foundation for modeling color-semantic and cognition behaviors. The proposed studies bring new empirical methodologies to this research issue (precise color-video stimuli and advanced paradigm designs), and new formal models for the analysis of data: the Batchelder- Bershad Rating system and the Romney-Batchelder Consensus Theory. These two models are powerful research advances for issues of cognition and color-semantics. Proposed experiments employ designs that will assess both cases of color-judgment in isolation and color-judgment in context. The empirical results will permit critical evaluation of both existing theory and findings. The research will generate normative data for several different linguistic populations (i.e. English, Japanese, Vietnamese, Korean), and gender differences for each population. Results for these samples will be compared against existing results from similar linguistic populations and will serve as strong tests of existing color-semantic theories. Preliminary research in cognition and color theory presents alternative models to accepted theories, and pilot research suggests that the proposed studies are empirically feasible and promise informative results.

Investigators studying the neural basis of cognition search for robust and meaningful relations between important neural stages and mental states defining complex psychological sensations. This approach has characterized the study of human color vision. The early stages of neural processing involved in the perception of color from environmental light have been mapped from retinal input structures to neural processing structures in the brain. This earlier research has adopted the Trichromatic model of color vision, which assumes three different retinal light detectors, each of which codes a different part of the visual spectrum and uses a different neural processing channel. This model has been widely used for modeling both early visual processing and higher-order color sensations. However, recent studies in the molecular genetics of color vision have demonstrated that a large number of individuals in the general female population can express more than the standard three retinal visual photopigments. Thus, it is possible that the trichromatic assumption of a strictly three-channel color vision system may not be appropriate for those individuals. These individuals may have retinas composed of more than three types of cone photoreceptor visual pigments and may experience color sensations which differ from those experienced by individuals expressing only three "normal" pigments. This research will assess the color perception of individuals grouped according to classes of color-vision genes as identified through genetic assays. Individuals identified as Dichromats (two color-vision channels) and Trichromats (the usual three color-vision channels), as well as individuals genetically determined to have non-standard photopigment genetic variations will be examined. In these experiments, individuals' color perception capabilities will be assessed using two methods, a standard method long used and found in the literature and another newly developed method. Additionally, the research will conduct a parallel line of investigations exploring the perceptual consequences of various mutations in an important color-vision gene. This research will clarify the extent to which gender differences in color appearance behaviors are mediated by variations in color-vision gene expression. The results will also provide evidence about the adequacy of the three-channel processing assumption and the Trichromatic model of color perception. In addition, these experiments will help us understand a number of technical issues related to the influence of genetic mechanisms on color vision. This research, because of its implications for people who may have more than three photopigment classes, may impact a variety of industrial applications for coding color appearances (e.g., three-phosphor primaries used in color television technologies, environmental lighting applications, and many others.) which rely on the Trichromatic model. This POWRE grant, in addition to the specific research involved, should advance the PI's prominence as a research scientist, mentor and scholar in this area of research.