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THE REVERSE MÜLLER‐LYER ILLUSION AND ‘ENCLOSURE’
Author(s) -
FELLOWS BRIAN J.
Publication year - 1968
Publication title -
british journal of psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.536
H-Index - 92
eISSN - 2044-8295
pISSN - 0007-1269
DOI - 10.1111/j.2044-8295.1968.tb01151.x
Subject(s) - enclosure , illusion , rectangle , optical illusion , scaling , psychology , line (geometry) , mechanics , optics , geometry , cognitive psychology , physics , mathematics , electrical engineering , engineering
A reversal of the normal Müller‐Lyer illusion occurs when relatively short lines are placed midway between the ingoing and the outgoing fins (Fellows, 1967). Gregory's (1967) explanation of this effect in terms of constancy scaling is unsatisfactory. An alternative hypothesis is proposed in which the reverse illusion is due to the enclosing effect of the ingoing fins. This hypothesis is supported by an experiment showing that an equivalent‐sized non‐fin enclosure (rectangle) has the same expansion effect upon a short line. The experiment also supported the argument that the reduction in the extent of the reverse illusion with increases in the length of the inter‐fins line, and the eventual emergence of the normal illusion, are due to the progressive weakening of the enclosure effect and the strengthening of another effect specifically involving the pattern of the fins. The relation between enclosure and contrast is discussed.