This paper presents an illustration of the complementary use of the algebraic and the ‘information processing’ points of view in the domain of experts' choice. Our main proposition, supported by experimental results, is that the decision process itself can be represented by an algebraic rule. A systematization of this approach leads to the general notion of choice polynomials. Such polynomials are able to translate into mathematical terms psychological hypotheses and/or observations. They also give a new insight into the nature of the so‐called lexicographical