Thesis (Ph. D.)--University of Sydney, 2008. / Includes graphs and tables. Title from title screen (viewed June 3, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Department of Psychology, Faculty of Science. Degree awarded 2008; thesis submitted 2007. Includes bibliographical references. Also available in print form.

Forty-two college aged participants took part in a mixed repeated measures factorial design experiment that assessed color memory as a function of condition (practice with feedback, practice without feedback and no practice), dimension (hue, saturation and lightness) and color (red, yellow, green and blue). Attention was focused on the distinction between memory color and color memory, color experience and preference, mechanisms of color perception and theories of color vision (see below). Only two significant effects were found: a significant main effect for dimension and a significant interaction between dimension and color. Pearson correlations were assessed between color memory and color experience, color preference and observer imagery. None of the correlations were significant. The results of the experiments revealed that practice does not have a significant effect on color memory and the conclusion, therefore, is that the phenomenon of color memory is not improved by practice. A tentative explanation involves the early stages of color processing which are presumed to be computational in nature and to take place independently of cognitive processes such as learning and memory, which do not take place until visual information has reached the extrastriate areas. By that time, color information has been combined with information about context, in area V4 of the human visual cortex (Zeki & Marini, 1998). Although it has been shown through this experiment that practice does not improve memory for color, the possibility remains that practice may improve memory color for specific objects - namely ecologically relevant stimuli - since memory color involves higher order processing, such as learning and memory. / Master of Science

A large number of studies in psychology and cognitive neuroscience suggest that the left and right cerebral hemispheres have differences in specialization of processing. The left hemisphere tends to be specialized for complex capacities such as language and numbers, whereas the right hemisphere typically shows advantages for visuospatial attention and recognition of nonverbal form. The present study was designed to investigate whether these functional cerebral asymmetries would extend to working memory tasks. It was hypothesized that the left hemisphere would have more advantage for accurate responses to a Number-based memory task, whereas the right hemisphere would be relatively advantaged for accurate responses on a Color-based memory task. For the Color-based memory task, we used a Corsi-Block memory task (4x4 grid). For the Number-based memory task, we used a string of 8 digits. In each case, to-be-remembered stimuli were constructed sequentially, such that participants (N = 39) had to form and maintain the image in working memory. Participants then compared these remembered stimuli with flashed images that appeared either on the left or right edge of the screen. We recorded the correct responses and the response time. The left hemisphere appears to be advantaged for accurate responses when the memory stimuli are numerical in nature, whereas the right hemisphere has more advantage for accurate responses on the color-memory task.

Fifty-two college-aged observers participated in an experiment assessing color memory via a PowerPoint '97 computer display program which varied one of the three dimensions of hue, saturation and lightness at a time. Consistent with previous research, errors were greater for the lightness conditions followed by saturation, and least for hue conditions Additionally, a signal detection analysis indicated that d-prime was greatest for the hue conditions, less for saturation and lowest for lightness conditions. There were also significant but unpredicted differences in response criterion which may reflect task difficulty. Scores on the Vividness of Visual Imagery Questionnaire (Marks, 1973) were, in general, not correlated with performance on these color memory tasks, inconsistent with previous research. The role of complexity of neuronal circuitry, the significance for opponent-process, trichromatic and retinex color vision theories and the relationship to Sokolov's model of color memory were discussed. Also, it was concluded that investigators of color memory using a computer display are well-advised to calibrate the monitor with a colorimeter because the internal computer units may be unreliable indexes of changes in hue, saturation and lightness. / Ph. D.