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REASONING WITH NEGATIVES
Author(s) -
EVANS J. St B. T.
Publication year - 1972
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.2044-8295.1972.tb02102.x
Subject(s) - statement (logic) , psychology , negation , denial , social psychology , inference , cognitive psychology , epistemology , linguistics , artificial intelligence , computer science , philosophy , psychoanalysis
Two experiments are reported on the effect of negation on reasoning with conditional rules. In Expt. I significantly more affirmative than negative statements were denied by a valid inference ( modus tollens ), and significantly more negative than affirmative statements were affirmed by a fallacious inference ( affirmation of the consequent ). Subjects made their inferences by choosing from a list of possible conclusions, so that, for example, an affirmative statement, p , could be denied by selecting the negative conclusion, not p. It was hypothesized that the greater difficulty experienced by subjects in the denial of not p by a choice of p might be due to the additional intermediate step of double negation. i.e. not not p , which is involved. The results of Expt. II suggested, however, that the difficulty lies in subjects' inability to infer that a negative statement is false, rather than in the process of transforming a double negative into an affirmative.