Abstract
30 undergraduates attempted to solve 6 "who-done-it" type deductive reasoning problems which varied in (a) number of relevant dimensions, (b) logical connective employed, and (c) affirmative vs. Negative statement of information. Written protocols were classified into 5 modes of representation, with 1 the matrix clearly superior to other forms for affirmatively stated problems. Affirmatively stated problems were solved more easily than negative problems, with other task variables having little effect. The effect of the task variables on solution rates seemed dependent on their influencing the modes of representation ss employed. Possible reasons for the effectiveness of the matrix mode of representation are discussed. (PsycINFO Database Record (c) 2006 APA, all rights reserved)