Sticky rules: integration between abstract rules and specific actions.

The authors manipulated repetitions and/or changes of abstract response rules and the specific stimulus- response (S-R) associations used under these rules. Experiments 1 and 2, assessing trial-to-trial priming effects, showed that repetition of complete S-R couplings produced only benefits when the rule also repeated (i.e., rule-S-R conjunctions) but costs when identical S-R couplings repeated while rules changed. In Experiments 3 and 4, the authors manipulated amount of experience with specific rule-S-R conjunctions and demonstrated integration between rules and S-R couplings in terms of cumulative practice effects. However, unlike short-term priming effects, cumulative practice supported generaliza- tion of experience with specific S-R couplings across rule boundaries (Experiment 4). Results are discussed in terms of constraints on models of hierarchical control and in terms of qualitatively different ways in which people profit from very recent experiences (i.e., all-or-none access to working memory representations) versus cumulative experience (i.e., similarity-based retrieval from long-term memory). In models of cognitive control, it is often posited that selec- tion occurs in a hierarchical manner (e.g., Koechlin, Ody, & Kounelher, 2003; Norman & Shallice, 1986). On one level, an abstract set of rules, stimulus dimensions, or possible response options is chosen, which in turn constrains selection on a lower level that then determines the specific response. Behavioral and brain imaging evidence (e.g., Gopher, Armony, & Greenshpan, 2000; Koechlin et al., 2003) is generally compatible with such a distinction between levels of selection. However, an open question is how, exactly, the different levels of selection are interrelated. One theoretical possibility is that control is strictly hierarchi- cally organized: Once an instructed task set has configured the cognitive system, its job is done, and it plays no further role in the lower level selection process itself. For example, if a task requires a left keypress for red stimuli and a right keypress for green stimuli, then the task-level codes would be responsible for config- uring the cognitive system to process only the color of the object (thereby ignoring other dimensions) and to establish the relevant S-R links. However, according to this account, the task-level codes are irrelevant during the response-selection process itself and therefore would not make contact with the stimulus or re- sponse codes involved in an actual selection episode. The advan- tage of this type of modular selection architecture is that changes could be carried out on one level without affecting efficiency on the remaining levels. For example, if a particular action is learned under Rule A and then reused under Rule B, full transfer regarding the lower level action selection process should be expected. A second possibility is that codes representing abstract rules and codes representing concrete actions become integrated into a com- mon representation during selection. We refer to this as the cross- level integration model. According to this model, the codes re- sponsible for task-specific selection settings are active during the response selection process and can become associated with lower level stimulus-response codes. A straightforward implication of this model is that even when two selection episodes are based on identical lower level stimulus or response codes, they would be integrated into distinct representations if they occur within differ- ent abstract rule settings. In contrast with the strictly hierarchical model, no transfer across abstract rules would be possible. Al- though an integrative process that builds associations across levels seems to contradict the very definition of an abstract rule, it may nevertheless be useful. For example, with such integrated repre- sentations in place, activation of an abstract rule may coactivate a specific action that is frequently associated with that particular rule (or vice versa) and thereby better prepare the cognitive system for regularities that are not contained within one particular level of selection. In this research, we explored to what degree integration across levels of selection occurs. We developed a new variant of the so-called task-switching paradigm, which allows an unambiguous test of the degree of cross-level integration. Using this paradigm, in Experiments 1 and 2, we examined integration across levels in the context of trial-to-trial priming effects. In Experiments 3 and 4, we adapted the same basic paradigm to look at potential cross- level integration effects of cumulative experience.