Vm. Sloutsky et al., COGNITIVE MECHANISMS OF DEDUCTIVE REASONI NG - PROBABILITY, PREVIOUS KNOWLEDGE OR THE FORMAL LOGIC - DISCUSSION, Psihologiceskij zurnal, 19(3), 1998, pp. 141
Studies of deductive reasoning have revealed a number of systematic er
rors made by reasoners. Some of these systematic errors, belief bias a
nd content bias are the focus of this paper. Two hundred and sixty two
university students participated in the study. The results indicate t
hat when the premises of the most simple forms of syllogisms include s
imple mathematical content (e.g., numbers), the acceptance of the conc
lusion as logically following from the premises drops from 90-95% when
the conclusion is believable, to 25-30% when the conclusion is unbeli
evable. However, there is no comparable effects when the premises are
concerned with non-math content. Thus the paper provides evidence that
belief bias differs across contents of reasoning.