In order to determine whether preference in object matching tasks measures participants’ strategy or tells us something about the salience of relations between corresponding concepts, we conducted three experiments. In Experiment 1 and Experiment 2, we approached this question by measuring the ease with which adult participants process different relations when they are under strategic instruction. When asked to group objects based on thematic or taxonomic relatedness, participants were slower (Experiment 2) and tended to make more errors (Experiment 1-2) when they had to find a taxonomically related pair than when they searched for a thematically related one. In Experiment 3, participants performed a standard matching task and their eye-movements were monitored throughout. In addition to the strong thematic preference in participants’ choices, we measured longer fixations to thematically related objects than taxonomic competitors. Even though thematic and taxonomic information appear to compete for selection in early phases of observation, thematic conceptual relations appear to be more salient and preferred, independently of instruction.