Information-processing demands of transitive inference.

The information-processing demands of transitive inference problems were investigated with a probe reaction-time (RT) secondary task. Two versions of a primary task were used: the standard three-term inference problem and a matched verification task that did not require premise integration. In the first two experiments the premise and target-matching components of the primary task were presented sequentially. For the transitive inference task, probe RT was especially slow when the probe occurred during the second premise phase, but no such effect was found with the matched verification task. This implies that premise integration imposed an increased load on processing resources. A third experiment showed that the processing demand associated with premise integration also occurred with simultaneous presentation. Other variations in problem form (e.g., premise markedness, negation, and pivot search) did not influence probe RT, although they are known to affect solution time. Thus, solution time and measures of processing load may be independent.