Context Effects on Remembering and Knowing: The Expectancy Heuristic David P. McCabe Colorado State University David A. Balota Washington University in St Louis Three experiments are reported examining the effect of context on remember– know judgments. In Experiments 1 and 2, medium-frequency words were intermixed with high-frequency or low-frequency words at study or at test, respectively. Remember responses were greater for medium-frequency targets when they were studied or tested among high-frequency, as compared with low-frequency, words. The authors proposed a decision-based mechanism called “the expectancy heuristic” to explain why remem- ber responses were more likely when items were studied or tested in the context of words that were relatively less distinct. According to the expectancy heuristic, when items on a recognition test exceed an expected level of memorability they will be given a remember judgment but when they do not, but are still more familiar than new words, they will be given a know judgment. Experiment 3, which varied expectancies about the strength of tested targets, demonstrated the use of the expectancy heuristic, indicating that it operates by selectively influencing the remember criterion rather than by influencing recollection of studied items. Keywords: context, remember– know, recollection, recognition, signal detection The remember– know procedure was originally introduced to demonstrate that people could discriminate between the subjective states of awareness associated with autonoetic and noetic con- sciousness (Tulving, 1985). Tulving (1985) argued that remember responses were given when subjects could mentally travel back to the moment in time in which they had originally experienced an event, that is, autonoetic consciousness. In contrast, know re- sponses were given when subjects believed items were studied but they did not experience recovery of contextual information, that is, noetic consciousness. A plethora of research using the remember– know procedure has revealed systematic effects of different variables on remember and know responses, leading to evidence of functional dissociations of the two responses. The variables that selectively affect remember responses are typically those that encourage more elaborate pro- cessing at encoding. For example, deeper levels of processing (Gardiner, 1988), generating studied items (Gardiner, 1988), and more elaborative rehearsal strategies (Gardiner, Gawlick, & Richardson-Klavehn, 1994) all increase remember responses. By contrast, divided attention at study selectively reduces remember judgments (Parkin, Gardiner, & Rosser, 1995), as does the inges- tion of sedative– hypnotic drugs, such as midazalom (Huron, Gier- sch, & Danion, 2002). Remember responses are also enhanced for certain stimulus manipulations, such as presenting items as pic- tures as compared with words (Rajaram, 1996) or presenting words of lower frequency (Joordens & Hockley, 2000) or unusual or- thography (Rajaram, 1998). Other variables, such as masked prim- ing at test, influence know responses but have little effect on remember responses (e.g., Rajaram, 1993). Still other variables, such as increasing study duration, increase both remember and know responses (e.g., Gardiner, Kaminska, Dixon, & Java, 1996). Remember and know judgments are typically interpreted as indices of different memory systems or processes. For example, dual-process accounts of memory suggest that remember re- sponses are more likely to arise from recollection of past events, whereas know responses, or an estimate based on know responses (i.e., the independence remember– know estimate), are more likely to reflect familiarity-based recognition (Yonelinas, 2002; Wixted & Stretch, 2004). Support for the dual-process account comes from the convergence of different methods of measuring recollection, such that variables that affect remember responses also affect recollection estimates from process dissociation and the shape of receiver operating characteristic curves (Yonelinas, Kroll, Dob- bins, Lazzara, & Knight, 1998). Similarly, Tulving’s (1985) orig- inal account of remember– know was based on the notion that remember responses reflected the conscious state of awareness associated with output from the episodic memory system, whereas know responses reflected a state of awareness associated with output from the semantic memory system (see also Gardiner, 1988; Rajaram, 1993; Wheeler, Stuss, & Tulving, 1997). Context Effects on Remember and Know Judgments The bulk of experimental work on remember– know judgments has focused on how different encoding and retrieval manipulations affect the reporting of these responses. Less attention has been paid to the decision processes involved in defining what constitutes a remember or know judgment, though obviously decision processes must be important to the use of any subjective report. The present investigation concerns the way in which remember– know judg- ments are used as a function of different encoding and retrieval contexts, with context referring to the type of items that are David P. McCabe, Department of Psychology, Colorado State Univer- sity; David A. Balota, Department of Psychology, Washington University in St. Louis. We would like to thank Stephanie To and Chelsea Beman for data collection in Experiments 1 and 3, respectively. Correspondence concerning this article should be addressed to David P. McCabe, Department of Psychology, Colorado State University, 1876 Campus Delivery, Fort Collins, CO 80523. E-mail: david.mccabe@colostate.edu Journal of Experimental Psychology: Copyright 2007 by the American Psychological Association Learning, Memory, and Cognition 2007, Vol. 33, No. 3, 536 –549 0278-7393/07/$12.00 DOI: 10.1037/0278-7393.33.3.536 536