A method is presented for choosing high-contrast sets of colors for additive color mixers (e.g., CRT). The method is based on data about target-location performance of human observers and adapts the color sets to the gamut of the color processor in use. The method produces any specified number of colors spread as far from each other as possible in color space to maximize contrast. Applications of high-contrast sets of colors are indicated, illustrative results are presented and discussed, and variations of the method are suggested.

The principle that things are easier to find if they contrast with their environment is expressed quantitatively. Two indices of conspicuousness, relative fixation rate and search time, are shown to be related to the color difference between the target and background objects. The color difference equations used are CIELAB, CIELUV, and the Judd modification of the index of fading. None of the equations is superior to the others. Furthermore, neither Judd's modification nor Semmelroth's adjustment accounts for effects of surround lightness. It is suggested that color difference be used as a tool for design and evaluation of visual displays, for construction of color codes to optimize search time, and as a generalization of chromatic contrast in psychophysical research.

Color coding for small symbols is discussed. An exploratory Jtudy of visual search on an electronic display is described. Colors of Jmall symbols (subtending less than 30') are less dihtinct than those qf I" and 2" symbols. The study shows that Jurround luminance is a factor having its own effect that also alters the effect of symbol size on color perception. Humun performance using small symbols is better when turget symbols have a larger color difference (CIELUV) from both distructor symbols and the surround. The effect of reduced symbol size is accentuated by differences between surround luminance and symbol luminances. To predict human performance in tasks requiring rapid location of small symbols, ane should consider surround and symbol luminances as well as color differences. CCC 0361 -231 71881040226-09$04.00 COLOR research and application 29 0.014 0.014Mean square

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Background Childhood adversity (CA) is commonly associated with an increased risk of subsequent psychopathology. It is important to identify potential mediators of this relationship which can allow for the development of interventions. In a large population-based cohort study we investigated the relationship between CA and late adolescent psychopathology and early adolescent candidate mediators of this relationship. Methods We used data from three waves (n = 6039) of Cohort 98′ of the Growing up in Ireland Study (age 9, 13 and 17). We used doubly robust counterfactual analyses to investigate the relationship between CA (reported at age-9) with psychopathology (internalizing and externalizing problems), measured using the Strengths and Difficulties Questionnaire at age-17. Counterfactual and traditional mediation was used to investigate the mediating effects of the parent-child relationship, peer relations, self-concept, computer usage and physical activity. Results CA was associated with an increased risk of internalizing and externalizing problems at age-17. Parent-child conflict mediated 35 and 42% of the relationship between CA and late adolescent externalizing problems and internalizing problems, respectively. Self-concept and physical activity mediated an additional proportion of the relationship between CA and internalizing problems. These results were robust to unmeasured confounding. Conclusions Parent-child conflict explains more than a third of the relationship between CA and later psychopathology. Self-concept and physical activity explain the additional proportion of the relationship between CA and internalizing problems. This suggests that these factors may be good targets for intervention in young people who have experienced CA to prevent subsequent psychopathology.