Recent proposals emphasize the role of learning in empirical markers of conflict adaptation. Some of these proposals are rooted in the assumption that contingency learning works not only on stimulus-response events but also on covert processes such as selective attention. In the present study, we explored how these learning processes may apply to trial-to-trial modulations of selective attention, mirroring the sequential nature of congruency sequence effects. Two groups of participants performed a four-choice Stroop task in which the color to which they responded on each trial acted as a probabilistic predictor either of the external response to be emitted on the next trial, or the congruency level (and therefore control demands) on the next trial. The results showed clear effects of sequence learning for external responses, but no evidence of learning about sequential stimulus-conflict associations. The implications of these results are discussed in relation to other learning-based phenomena of conflict adaptation and suggest that learning of stimulus-control associations is strongly constrained by event boundaries.