When vaccinating against information reduction works and when it does not work

Practice not only affects how information is processed, but also which information is processed. The Information-Reduction Hypothesis (i.e. Haider & Frensch, 1996) holds that — with practice — irrelevant task information (i.e. information that is not logically needed to correctly perform the task) is discarded from processing. Recently, Gaschler and Frensch (2007) have demonstrated that Information Reduction is not affected by the frequency with which individual task configurations are presented: well-practiced and little-practiced irrelevant task configurations are discarded at the same point in time during practice; Information Reduction is thus an item-general phenomenon. These findings suggest that Information Reduction is at least in part a consequence of top-down, voluntary control. In the present research, we ask how tasks can be constructed such that Information Reduction is avoided. Our results show that item-general Information Reduction is observed even when it leads to severe processing costs (i.e. errors). On the whole, the present results are in line with models of skill acquisition incorporating top-down modulation (e.g. Haider & Frensch, 2002) and are incompatible with purely data-driven accounts of skill acquisition (e.g. Logan, 1988; Nosofski & Palmeri, 1997; Palmeri, 1997; Rickard, 2004).