In this paper we discuss the strength of the adversary argument in establishing lower bounds on the complexity of certain sorting-type problems. The relationship between adversary argument and so called information theory argument is indicated and the efficiency of adversary argument relative to the type of comparisons involved in the computation of a problem is investigated. The results concern the effect of polynomial comparisons on lower bounds. In certain cases (MIN and MERGE problems) by using polynomial comparisons we are able to obtain assymptotically the same lower bounds as those established when comparisons without arithmetics are used.