A solution to the problem of context-dependent recognition memory is presented in terms of the item, associated context, and ensemble (ICE) theory. It is argued that different types of context effects depend on how context information is encoded at both learning and retrieval. Matching associated context in memory and a retrieval cue produces increases in both hit and false alarm rates and may not be accompanied by a change in discrimination. Integrating item and context information in an ensemble and matching ensemble information in memory and a retrieval cue produces context-dependent discrimination. Empirical support for these predictions is presented.

A number of prior studies have not found declines in recognition performance when testing occurs in an environmental context that is different from the learning context. These findings raise serious problems for global activation theories of recognition which predict that hit and false alarm rates will decline when the test context does not match the learning context. Environmental context was manipulated as a unique combination of foreground color, background color, and location on a computer screen in three experiments using intact-rearranged recognition testing and two experiments using single-item testing. Changes in context resulted in reduced hit and false alarm rates as predicted by global activation theories in all five experiments. Mental reinstatement of the learning context was also examined. The results indicated that subjects did not use a mental reinstatement strategy in these experiments.

The effects on recognition of changes in environmental context between learning and test are examined. Acontext effect occurs when memory tests that take place in an environmental context that is different from the learning context produce consistent differences in performance. Aformal model of context-dependent recognition within a global activation framework is presented. The model generates the predictions that (1) context effects will be present when items are tested in a new context that was not seen during learning and (2) context effects will be absent or very small when items are tested in a context that was experienced during learning but that differs from the context in which the test item was learned. Both predictions were verified in an experiment that varied the nature of the different-context test within subjects. Implications for research concerned with contextdependent recognition are discussed.Prior studies that have tested recognition memory in an environmental context that is different from the learning context have produced inconsistent results. In a number of studies

Theoretical analyses and empirical studies address the issue of how context-dependent recognition is affected by changes in the relative strength of retrieval cues. Analyses of global memory models based on K. Murnane and M. P. Phelps' (1994) general context model showed that if context strength is held constant, context effects are predicted to either increase or remain unchanged when item strength increases. In contrast, the outshining hypothesis (S. M. Smith, 1988Smith, , 1994 predicts that context effects will decrease as item strength increases. Three studies are reported in which item strength was manipulated with spaced repetitions, study time, or a levels-of-processing manipulation. The results support the general context model. Implications for the outshining hypothesis and for global memory models are discussed.

Age differences in the processing of contextual information were investigated using the Item, associated Context, and Ensemble (ICE) model (K. Murnane, M. P. Phelps, & K. Malmberg, 1999), a general global matching model of recognition memory. In two experiments, young and older adults studied words in environmental contexts and were tested in both the same and different contexts. Patterns of context effects for hit rate, false alarm rate, and d' suggest that older adults process associated context, but have difficulties integrating items and context into an ensemble. Thus, older adults appear to have a specific, rather than a general, deficit in processing contextual information. A deficiency in ensemble processing may be responsible for the prevalent finding that older adults show poorer recognition memory performance than young adults.