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A Cross-Cultural Study of the Strength of the Muller-Lyer Illusion as a Function of Attentional Factors

Carlson, Julia A.; Davis, Clive M.
Publication Year:
Report Number:
ETS Research Bulletin
Document Type:
Page Count:
Subject/Key Words:
National Institute of Mental Health, Social Science Research Council, Foreign Area Fellowship, Africa, Attention, Cross-Cultural Studies, Muller-Lyer Illusion, Perception, Uganda


In order to investigate the role of attentional factors in cross-cultural differences in illusion susceptibility, Muller-Lyer illusion stimuli were administered to several samples of adult male Ss, in Uganda and the United States under two instructions. One instruction directed S to attend to the horizontal lines and to withhold attention from the angled lines. The other instruction merely asked him or her to tell which of the two horizontal lines was longer. When the horizontal and oblique segments were separated and of different colors, there were no instructional differences. When the angled lines joined the horizontals and the stimuli were all of one color, instructional differences were found. The lesser susceptibility of the African Ss was replicated.

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