In a human causal learning experiment, we investigated cue selection effects to test the comparator theory ( Denniston, Savastano, & Miller, 2001 ; Miller & Matzel, 1988 ). The theory predicts that the occurrence of cue selection is independent of whether the relevant learning trials are presented in a standard forward manner or in a backward manner and that within-compound associations are of equal importance in both cases. We found that the strength of the cue-selection effect was positively correlated with knowledge of within-compound associations in the backward condition but not in the forward condition. Furthermore, cue-selection effects were less pronounced in the former than in the latter condition. These results are at variance with the comparator hypothesis but are in agreement with a modified associative theory and with the suggestion that retrospective revaluation might be due to rehearsal processes.