On the Status of Cue Independence as a Criterion for Memory Inhibition: Evidence Against the Covert Blocking Hypothesis Peter D. Weller Universidad de Granada Michael C. Anderson MRC Cognition and Brain Sciences Unit, Cambridge, England Carlos J. Gómez-Ariza Universidad de Jaén M. Teresa Bajo Universidad de Granada Retrieving memories can impair recall of other related traces. Items affected by this retrieval-induced forgetting (RIF) are often less accessible when tested with independent probes, a characteristic known as cue independence. Cue independence has been interpreted as evidence for inhibitory mechanisms that suppress competing items during retrieval (M. C. Anderson & Spellman, 1995). Several authors, however, have proposed that apparent cue independence might instead reflect noninhibitory cue- dependent blocking mechanisms. In this view, when participants receive an independent probe test, they do not limit themselves to those probes but instead recall study cues covertly to aid performance. This strategy is thought to be self-defeating, because it reintroduces cues that instigate blocking, lending the appearance of generalized inhibition. M. C. Anderson (2003), in contrast, proposed that covert cuing masks cue-independent forgetting by providing a compound cuing advantage. Here, we replicated cue-independent RIF and documented how access to the original study cues influences this effect. In Experiments 1–2, we found that overtly providing category cues on independent probe tests never increased RIF. Indeed, when we provided categories selectively for items that should suffer the most blocking, a sizable reversal of RIF occurred, consistent with the masking hypothesis. Simply asking participants to covertly retrieve categories eliminated cue-independent RIF, contradicting predictions of the self-inflicted blocking account. Far from causing cue-independent forgetting, covert cuing masks it. These findings strongly support the inhibition account of RIF and, importantly, may explain why cue-independent forgetting is not always found. Keywords: inhibition, forgetting, retrieval, interference, covert cuing A fundamental problem in the science of memory is to isolate the mechanisms underlying the forgetting of everyday experience. Over the last century, a number of mechanisms have been pro- posed that may contribute (see M. C. Anderson & Bjork, 1994, for a review). For example, forgetting may sometimes reflect retrieval failure arising from competition with related traces (McGeoch, 1942). By this account, the cues one uses to retrieve a trace become associated to other memories that compete for retrieval (e.g., J. R. Anderson, 1974; Mensink & Raaijmakers, 1988), with stronger associations blocking weaker ones. Over the last two decades, however, evidence has accumulated indicating that for- getting often arises not merely from competition but from adaptive control processes that resolve competition between memories that contend for selection (M. C. Anderson, 2003; Levy & Anderson, 2002). Retrieval competition is thought to be resolved by an inhibition process that reduces competitor activation, aiding target retrieval. The aftereffects of inhibition on the competitors render them less accessible, contributing to forgetting. The potential contribution of inhibition can be illustrated with the retrieval practice (RP) paradigm (Anderson, Bjork, & Bjork, 1994). In a common variant, participants encode category-exemplar pairs (e.g., Fruit–Orange; Fruit–Banana; Clothes–Shirt) and later perform retrieval practice on half of the items from half of the categories (retrieval practice phase). That is, given the category and a stem (e.g., Fruit Or__), participants are asked to recall the studied exemplar. In a final phase, exemplars are tested with their category and the first letter (Fruit B___). Naturally, one finds superior recall for the items that participants practiced (hereinafter, Rp+ items). More in- This article was published Online First October 8, 2012. Peter D. Weller, Departamento de Psicología Experimental, Universidad de Granada, Granada, Spain; Michael C. Anderson, Memory Research Group, MRC Cognition and Brain Sciences Unit, Cambridge, England; Carlos J. Gómez-Ariza, Departamento de Psicología, Universidad de Jaén, Jaén, Spain; M. Teresa Bajo, Departamento de Psicología Experimental, Universidad de Granada, Granada, Spain. This research was supported by Spanish Ministry of Science and Innovation Grants EDU2008-01111, CSD2008-00048, and PSI2008- 05607 to Carlos J. Gómez-Ariza and M. Teresa Bajo; Spanish Ministry of Science and Innovation Grant PSI2011-25797 to Carlos J. Gómez- Ariza; Grant P08-HUM-3600 from the Andalusian government to M. Teresa Bajo; and U.K. Medical Research Council Grant MC-A060- 5PR00 to Michael C. Anderson. Correspondence concerning this article should be addressed to Peter D. Weller, Departamento de Psicología Experimental, Facultad de Psicología, Universidad de Granada, Campus de Cartuja, s/n. 18071, Granada, Spain. E-mail: pdweller22@gmail.com This document is copyrighted by the American Psychological Association or one of its allied publishers. This article is intended solely for the personal use of the individual user and is not to be disseminated broadly. Journal of Experimental Psychology: Learning, Memory, and Cognition © 2012 American Psychological Association 2013, Vol. 39, No. 4, 1232–1245 0278-7393/13/$12.00 DOI: 10.1037/a0030335 1232