Does memory retrieval occur in a continuous or an all-or-none manner? The shape of the receiver operating characteristic (ROC) has been used to answer this question, with curvilinear and linear memory ROCs indicating continuous and all-or-none retrieval processes, respectively. Signal detection models (e.g., the unequal variance model) correspond to a continuous retrieval process, whereas threshold models (including the multinomial model and the recollection component of the dual-process model) correspond to an all-or-none process. In studies of source memory, Slotnick et al. (2000) and others have observed curvilinear ROCs (supporting the unequal variance model), whereas Yonelinas (1999) observed linear ROCs (supporting the dual-process model). We resolve these seemingly inconsistent results, showing that source memory ROCs are naturally curvilinear but can appear linear when nondiagnostic source information is included in the analysis. Furthermore, the unequal variance model accounted for both recognition memory and source memory ROCs, supporting a continuous process of memory retrieval.

We examined the contributions of decision processes to the rejection of false memories. In two experiments, people studied lists of semantically related words and then completed a recognition test containing studied words, unrelated lure words, and related lure words. People who said words aloud at study were less likely to falsely recognize related lures on the test than were those who heard words at study. We suggest that people who said words at study employed a distinctiveness heuristic during the test whereby they demanded access to distinctive say information in order to judge an item as old. Even when retrieving say information is not perfectly diagnostic of prior study, as in Experiment 2, in which participants both said and heard words at study, people persist in using the distinctiveness heuristic to reduce false memories.

Two experiments showed that older adults were worse than younger adults at judging the accuracy of their responses on source identification (i.e., who said what) and cued-recall tests. It is important to note that this age-related metamonitoring impairment occurred even after older and younger adults were matched on overall source accuracy and cued-recall accuracy. By contrast, older and younger adults showed comparable metamonitoring capacities when assessing the likely accuracy of old-new recognition judgments and responses to questions about general knowledge. These experiments are consistent with the misrecollection account of cognitive aging, which suggests that age-related memory impairments are due to older adults' vulnerability to making high-confidence errors when answering questions that require memory for specific details about recently learned events.

The authors analyzed source memory performance with an unequal-variance signal detection theory model and compared the findings with extant threshold (multinomial and dual-process) models. In 3 experiments, receiver operating characteristic (ROC) analyses of source discrimination revealed curvilinear functions, supporting the relative superiority of a continuous signal detection model when compared with a threshold model. This result has implications for both multinomial and dual-process models, bom of which assume linear ROCs in their description of source memory performance.Source memory refers to memory for the context in which information was acquired (Johnson, Hashtroudi, & Lindsay, 1993). For example, memory for the person with whom one is conversing or the place where one is conversing can be interpreted as source memory. In psychological experiments, source memory is typically assessed by asking participants to determine the origin of previously presented information, such as whether the information was presented verbally or visually, presented by a male or a female voice, or presented in one spatial location or another. As these examples imply, source memory depends on memory for autobiographical or episodic information. Various cognitive and neuropsychological findings have suggested that, to some degree, memory for source can be dissociated from item memory (see Dodson & Shimamura, 2000;Johnson, Kounios, & Reeder, 1994;Schacter, Harbluk, & McLachlan, 1984;Shimamura & Squire, 1987;Zaragoza & Lane, 1994). Indeed, various models of memory suggest a distinction that is related to differences between item and source memory (e.g., Gardiner, 1988;Hirst, 1982;Jacoby, 1991;Johnson et al., 1993;Mayes, Meudell, & Pickering, 1985;Tulving, 1972). Johnson et al. (1993) developed a useful framework for the analysis of source memory. In this "source monitoring" framework, the degree to which individuals identify the source of a memory depends, in part, on the kind of information that is acquired and remembered. That is, one can remember various aspects of a learning episode, such as perceptual information,

Three experiments explored the verbal overshadowing effect, that is, the phenomenon that describing a previously seen face impairs recognition of this face. There were three main results: First, a verbal overshadowing effect was obtained both when subjects were provided with and when they generated a description of an earlier seen face. Second, instructing subjects at the time of test to be aware of potentially competing memories did not improve, and may even have worsened, recognition performance when the subjects had generated a description of the target face. However, these instructions improved performance and eliminated the verbal overshadowing effect when subjects were provided with someone else's description of the target face. Third, recognition of the target face was disrupted when subjects described a completely different face, such as their parent's face or a face of the opposite sex. The results are discussed in relation to two potential mechanisms: source confusion between previously encoded visual and verbal representations of the face and a shift in processing of the test faces at recognition.