Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaves 80-84).

Thesis (Ph.D.)--University of Melbourne, Dept. of Optometry & Vision Sciences, 2009. / Typescript. Includes bibliographical references (p. 195-230)

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 40-46).

Thesis (B.A. (Hons.)) - University of Queensland, 2005. / Includes bibliography.

M. Phil. / Please refer to full text to view abstract / Prof. J.T. Ferreira

The colour vision of adult citrus psylla, Trioza erytreae, was investigated in the laboratory using the behavioural parameters: alightment and walking. Light green flushing leaves (under which the nymphs develop) were significantly preferred, visually, to dark green mature leaves for alightment. Diffuse reflectance spectroscopy showed (when expressed in the parameters of human colour vision) that flush has a very slightly longer dominant wavelength, and roughly double the reflectance and purity. Alightrnent frequency correlated almost equally well with "purity" (as noted by Moericke, 1952 et seq., in "yellow-sensitive" aphids) as with the aphidological colour parameter "long/short ratio" developed by Kennedy et al. (1961). Elucidation of the mechanism underlying the citrus psylla's alightment colour preference was initially attempted with a printed spectrum and several paint series of measured spectral characteristics. It was clear that T.erytreae belongs to the "yellow-sensitive" group of Homoptera, but it was impossible to distinguish which pararneter(s) of colour the psyllids were responding to. Phototactic (walking) response to the individual parameters of colour was therefore measured using a monochromator. The phototactic action spectrum (against wavelength) was tri-modal, with peaks in the yellow-green (YG), blue (B), and ultra= violet (UV). Rate of phototaxis was not influenced by bandwidth (roughly equivalent to purity), but was proportional to intensity (roughly equivalent to reflectance). To investigate the influence of the above three wavelength regions on alightment, use was made of a very simple flight chamber incorporating a target of coloured light. Yellow-green and UV light both independently stimulated alightment . Their effect was additive. Different thresholds indicated distinct YG and UV receptor systems. Blue light alone did not stimulate alightment, and was strongly alightment-inhibitory in combination both with YG and with UV light. On the basis of the above physiological/behavioural findings, a new alightment formula was drawn up for describing the hamopteran's apparent manner of alightment determining integration of surface reflectance. The flush preference and alightment distributions on the series of artificial surfaces were found to correlate slightly more accurately, on average, as well as more consistently, with the new formula than with previously-available colour parameters. These findings are placed in perspective to the literature, and their possible economic relevance is discussed.

Eighteen two-year-olds and twenty four-year-olds were studied as to their knowledge and use of eleven colour terms: BLUE,GREEN,RED,YELLOW,BLACK,WHITE,GREY,BROWN,PURPLE, ORANGE, and PINK. Level of acquisition was determined by a production (naming) task, a comprehension (selection) task, and a discrimination (matching) task. The objectives were to examine various performance differences in light of possible evolutionary, perceptual and environmental factors and aspects of general lexical development. Performance accuracy was found to have no correlations with the evolutionary order proposed by Berlin & Kay, nor did it reveal the strong conceptual groups of primary, non-primary and achromatic colours which have been proposed by other studies. In particular, the non-primary colours did not behave as a group in any of the analyses. Measures of input and practice obtained from parental questionnaires also showed few correlations of environment with task performance. For various reasons, this information was considered unreliable and no claims about environment as a determinant in naming behavior could be made. Performance was notably more accurate in four-year-olds than in the two-year-olds. More terms had been acquired by the older group than by the younger, the average being eight terms and two terms respectively, and six of the older group had acquired all eleven colour terms. Comprehension was more advanced for both ages than, production, although more terms were produced than were comprehended. No sex differences were found at all. Further analyses concentrated on production performance. As expected, the number of colour terms used increased with age and their use became more stable with age. There was no one colour term that appeared in all of the subjects' lexicons, but the colour terms most likely to appear were the primaries and the non-primary ORANGE. BLUE showed a marked, though not significant, preference at both ages and several possible reasons are suggested for this. GREY, as expected, appeared least frequently, followed by the achromatics. Colour terms used most accurately were ORANGE and PINK. These appear to be the first colour categories to emerge with separate labels, followed by the primary colours and GREY again ranking lowest. There were no terms which had been acquired by a significantly large number of two-year-olds and none by a significantly small number of four-year-olds. Primary terms as a group were also those most likely to be used incorrectly. Those terms most likely to be overextended by the younger subjects were also those without a stable referent, while for the older ones it was those terms which the subject already knew the correct use of. The actual errors did not seem to be based on any of the proposed perceptual properties of colour. It is suggested that the child at these stages does not organize his lexical or conceptual colour categories in terms of the adult distinctions of primary/non-primary/achromatic or of hue/saturation/brightness. Further in-depth examination might reveal a base of associative or contextual criteria instead of the random, ad-hoc guesses they appear to be in this study. It is further suggested that such organizational criteria are very individualistic and therefore will not fit the generalizations made by previous studies about colour-term acquisition. / Arts, Faculty of / Linguistics, Department of / Graduate

A model based on the laws of classical conditioning is posed as an explanation for the McCollough Effect, an orientation-specific color aftereffect. This model stands as an alternative to the color-coded edge detector hypothesis. Background and relevant issues are presented. Two experiments were performed. The first demonstrated that an auditory stimulus causes the effect to appear stronger to some subjects, a disinhibiting effect. It was also shown that some subjects experience spontaneous recovery of the effect after it has been extinguished.

The interest of the writer was directed toward the phenomena of color vision in 1927 as a result of attending concurrently two courses in the University of California touching upon the subject, but treating it quite differently with results far from mutually consistent. Prof. R. S. Minor, in his course on physical optics, discussed color vision from the physicist’s standpoint, making use of the Young-Helmholtz theory; while Prof. G. M. Stratton gave the psychological treatment, based upon the Ladd-Franklin theory, as a part of his general psychology. Several of the more obviously points of conflict impressed the writer so strongly that he was led to bring the matter to the attention of the professors concerned. At the resulting conference between the two, a number of demonstrative experiments were performed and from the discussion of these in terms of the various theories the writer profited much. However, many facts remained unreconciled, so the writer resolved to investigate the subject further should opportunity present itself. The following research is a beginning of that study.

The problem of this study was to ascertain the effects of selected color phenomena upon the identification and comparison of color by college students. Instruments used for this study were the Snellen Visual Acuity Chart, which measures crudely the the binocular visual activity of an individual; Pseudo-Isochromatic Plates for Testing Color Perception, which roughly determine red-green color deficiency; and the "Isoline Color Phenomena Perception Presentation," which determines how an individual identifies or compares selected color phenomena.