Operator effects in the choice of certainty factor algebras: an experimental study

One aspect of knowledge acquisition involves reaching an understanding of how an expert combines certainties in the course of reasoning. There are several distinct junctures in an inference process where certainties need to be combined. At the most elemental level, these include combining certainties of operands involved in the arithmetic, logical and relational expressions that can constitute a premise. As a basic frame of reference for acquiring knowledge about certainty treatments, there is a prescriptive mapping of operators into the joint and confirmative classes of certainty factor algebras. However, these prescriptions have not been empirically studied. Here, we report on an experiment conducted to test various hypotheses about actual behaviors of people in combining certainties for elemental operators. For each operator, we found behaviors to be consistent with prescriptions in some respects, but deviating from them in other respects. The result is an empirical base from which to launch efforts involving the acquisition of knowledge about how specific experts combine certainties at various junctures in inference processes.