Espino, Santamaria, and Garcia-Madruga (2000) report three results on the time taken to respond to a probe word occurring as end term in the premises of a syllogistic argument. They argue that these results can only be predicted by the theory of mental models. It is argued that two of these results, on differential reaction times to end-terms occurring in different premises and in different figures, are consistent with Chater and Oaksford's (1999) probability heuristics model (PHM). It is argued that (...) the third finding, on different reaction times between figures, does not address the issue of processing difficulty where PHM predicts no differences between figures. It is concluded that Espino et al.'s results do not discriminate between theories of syllogistic reasoning as effectively as they propose. (shrink)