Alexander William Pressey

Alexander William Pressey, (b.1939) is internationally recognized for developing an assimilation theory of visual illusions and nationally for contributions to Canadian public policy. Selected references and brief descriptions are provided.
Author
Assimilation theory of visual illusions. The theory proposes that the Müller-Lyer, Ponzo, Delboeuf, Baldwin and Titchener Circles illusions are reducible to a 3-element parallel lines illusion in which the phenomenal size of the focal stimulus is a weighted average of the focal and contextual stimuli. The average is inversely related to the distance between focal and contextual stimuli and directly related to the probability that the contextual stimulus will be processed, i.e, fall within the attentive field. A unique, and crucial, aspect of this theory adopts the Heisenberg-like notion that the measuring device modifies the percept by determining where attention will be deployed. A computational model allows patterns of means and variances to be predicted (in, for example, the Müller-Lyer figure) from the simultaneous variation of six stimulus and two free, but rigorously defined, organismic variables. The theory has also been extended, in a less rigorous manner, to illusions of shape (Hering figure) and displacement (Poggendorff and Holding patterns).
Selected References: A.W. Pressey and C.A Pressey, Perception and Psychophysics, 1992, 51(5), 423-436. A.W. Prysiazniuk and H. Kelm, Journal of Abnormal and Social Psychology, 1963, 67, 505-509.
Psychologist
Research Psychologist, Saskatchewan Training School, 1961-63; Personnel Selection Officer, Canadian Army (M), 1961-64; Lecturer, Assistant, Associate and Full Professor of Psychology, University of Manitoba, 1960-1996.
Military Officer
CA(M) 1956-1964. O/C Royal Canadian Armoured Corps, Camp Borden; 2/Lt. Lord Strathcona's Horse, Calgary; Capt. PSO, Moose Jaw, Edmonton, Vancouver. Retired, 1964.
Farmer
Owner and co-operator of Red Bandana grain farm, Starbuck, MB, 1973-1990.
Political Observer
Print, radio and television commentary on Canadian nationalism, bilingualism and multiculturalism, Western Canadian alienation, and specialized topics such as university hiring practices, psychometric testing, agricultural subsidies, and global warming. Libertarian candidate, 1995.
Selected Reference: Doern, R. The battle over bilingualism. Cambridge Publishers. 1985.
Biography
b. Ethelbert, Man. 8 Feb. 1939; s. William and Anna (Kunka) Prysiazniuk; e. Univ. of Manitoba B.A. 1959, M.A. 1961; Univ. of Alta. Ph.D. 1965; m. Joyce d. Hermon and Bertha Hedison 16 May 1959; children: Cindy Dawn, Heather Lynn, Christopher Alexander.
Recreations: hockey, fastball, curling, golf.
Selected References: Canadian Who's Who, University of Toronto Press, 1987; Ewanchuk, M. Vertical Development, A new generation of Ukrainian Canadians, Ewanchuk Publishing, 2000.
Honours
Elected Fellow of Canadian Psychological Association, 1973; Visiting scientist American Psycholocial Association, 1975; Invited speaker at universities and institutions at Milan, Frankfurt, Munich (Max Planck), Vanderbilt, Georgia, Kansas, Jamestown and St. John.

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