Further tests of theories of decision in an "expanded judgment" situation.

Abstract

Subjects were shown numbers on cards drawn from large packs in which the means and subject-decisions of the numbers varied from pack to pack, and were required to announce when they had decided that the mean of the whole pack was greater than, or less than, zero. The number of cards required for these decisions varied directly with the absolute value of the mean, as predicted both by the Cartwright-Festinger theory of decision and by a theory based upon the processes of statistical decision-making. However, the number of cards required was greater for the greater of the 2 values of subject-decision that were used, which confirmed the "statistical" theory but contradicted the Cartwright-Festinger theory to the extent that the latter was applicable to the experimental situation.