Previous research has found that when information stored in memory is discredited, it can still influence later inferences one makes. This has previously been considered as an editing problem, where one has inferences based on the information prestored in memory before the discrediting, and one cannot successfully trace out and alter those inferences. However, in the course of comprehending an account, one can potentially make inferences after a discrediting, which may also show influence from the discredited information. In this experiment, subjects read a series of reports about a fire investigation, and their opportunity to make inferences before a correction appeared in the series was manipulated. Subjects received a correction statement either directly following the information it was to discredit, or with several statements intervening. The results show that subjects w h o received the correction directly after the information it corrected made as many inferences based on the discredited information as subjects w ho received the correction later (and thus could presumably make many more inferences before the correction occurred). This suggests that discredited information can influence inferences made after a correction, as well as those made before. Several hypotheses accounting for this effect are proposed.

Several lines of research have suggested that information previously integrated into memory can influence inferences and judgments, even w h e n more recent information discredits it. A first experiment tested the prediction that information providing causal structure, versus being mentioned but otherwise unintegrated into the account, would lead to more influence, and found that subjects used both discredited and valid information affording causal structure to make inferences, but not incidentally mentioned information with the same content Experiment 2 found that w hen a plausible causal alternative accompanied the correction, subjects showed less influence from the discredited information than when the correction simply negated earlier information. The findingssuggest that the continued influence of discredited information depends on the causal structure it affords

The problem of access to prior cases in memory is a central Issue in the case-based reasoning Previous work on thematic knowledge structures has shown that using a complete exemplar of a thematic pattern allows access to the structure and related cases in memory. However, the knowledge and expectations provided by such structures can aid in planning and problem-solving. Therefore, to be most useful, the Information should become available before the Input pattern Is complete. Retrieval must therefore be possible based on only a subset of the features present In the full thematic pattern. This study investigated whether a pattern that contains elements predicting an outcome, but not the outcome itself, would result In access comparable to that found when a full pattern is used. The results showed that subjects were less successful accessing the thematic structure using partial patterns than they were when using full patterns. However, remindings based on partial patterns occurred more often than would be expected by chance. W e conclude that partial patterns contain some predictive features that can allow access to a thematic knowledge structure before the pattern Is complete.

Agents in a dynamic world must continue to comprehend and reason about events, even after they learn that previously encoded information about an event is incorrect. As a result, some mechanism is needed to modify incorrect information in memory, and allow one to use new, superceding knowledge instead. Ho w is misinformation suppressed in human memory? A study using a text understanding paradigm and a standard anaphoric inference task investigates this problem of updating memory. Subjects read a set of stories, half of which contained a conection, and were asked to make a speeded wordrecognition judgment for a probe word appearing after an anaphor sentence. Subjects in a short delay condition showed slower reaction times to correct referents in correction stories than in control stories that did not contain misinformation. Those in the longer delay condition showed no difference in reaction times to correct referents, but more priming for invalidated items in correction stories. These results suggest that misinformation can interfere with accessing correct information, but that an additional comprehension process, possibly suppression-like, may facilitate access to correct information after delay.

How can misreported information be effectively corrected? Wilkes and Leatherbarrow (1988) found that people relied upon invalidated information to answer questions despite their awareness of its inaccuracy, a phenomenon called the "continued influence effect" (Johnson & Seifert, in press). But corrections in which an assertion is made and then denied (e.g., "X is true ... actually, X is untrue") ma y violate important conversational assumptions. Grice (1967/1989) and others have argued that people expect speakers to offer only information that is both truthful and conversationally relevant; thus, people may seek interpretations for corrections that will incorporate both the literal meaning and the conversational implications of the contradictory statements. Our hypothesis was that corrections would be more successful when they explained why the original information was asserted. An empirical study showed that corrections that accounted for conversational implications (e.g., "X, which bad originally been believed because of Y, is actually untrue") could more effectively reduce the continued use of discredited information. Additionally, the results show that reiterating the literal content of a correction ma y actually be perceived as implying that the correction statement should be disbelieved. Since the conversational implications of corrections critically shape comprehension, their examination is crucial in domains (such as courtrooms, newspapers, and classrooms) where informational updates frequently occur.