Updating Accounts Following a Correction of Misinformation

Transcription

1 Journal of Experimental Psychology: Learning, Memory, and Cognition 1998, Vol. 24, No. 6, Copyright 1998 by the American Psychological Association, Inc /98/S3.00 Updating Accounts Following a Correction of Misinformation Hollyn M. Johnson Washington State University Colleen M. Seifert University of Michigan The research examined whether corrected influences anaphoric inferences people make during subsequent reading. Participants read a set of corrected- and no- stories and made judgments about probe words that were either appropriate or inappropriate anaphoric referents. At a short delay, the results showed less activation for appropriate referents that were corrections of. At longer delays, the activation of appropriate referents showed no significant difference, but probes were more quickly recognized than were inappropriate referents that were incidentally mentioned in control story versions. In all conditions, appropriate referents showed more activation than inappropriate ones. The results suggest that corrected can continue to influence on-line reading processes. When people comprehend accounts of events, they may encounter initial that is corrected later. For example, a news station may initially broadcast that several people died of food poisoning after eating at a Chinese restaurant but correct this later and say that a carbon monoxide leak in the victims' home was responsible instead. When this correction occurs, ideally, comprehenders would ignore the about the Chinese restaurant and use the carbon monoxide information to understand postcorrection references to "the cause of death" and "the liable parties." Failing to ignore the could lead to causal misunderstandings and continued prejudice against the innocent restaurant owners. However, a number of previous studies have provided evidence that discredited information can continue to influence later reasoning (Anderson, Lepper, & Ross, 1980; Johnson & Seifert, 1994; Ross, Lepper, & Hubbard, 1975; Thompson, Fong, & Rosenhan, 1981; Wilkes & Leatherbarrow, 1988; Wyer & Budesheim, 1987; Wyer & Unverzagt, 1985). In the present research, we used on-line measures to examine anaphoric inferences that are made after a correction of. Hollyn M. Johnson, Department of Psychology, Washington State University; Colleen M. Seifert, Department of Psychology, University of Michigan. This article is based on a dissertation submitted to the University of Michigan in 1994 by Hollyn M. Johnson. Portions of these data have been presented at the 16th meeting of the Cognitive Science Society, Atlanta, Georgia, August 1994; at the 3rd meeting of the Text and Discourse Society, Boulder, Colorado, August 1993; and at the 36th meeting of the Psychonomic Society, Los Angeles, November This work was supported by the Office of Naval Research under Contract N W-0492 to the University of Michigan. We thank Paul Price for sharing his computer expertise and Seema Shastri for her help with materials and participant testing. We also thank D. E. Meyer, Richard Nisbett, and Steve Lytinen for their comments on a draft of this article. Correspondence concerning this article should be addressed to Hollyn M. Johnson, Washington State University, Richland Campus, 2710 University Drive, Richland, Washington In texts that do not contain, typically people activate appropriate referents after reading an anaphor. For example, if people read about a burglar and then read that the criminal was apprehended, they should infer that criminal (the anaphor) and burglar (the referent) designate the same person. McKoon and Ratcliff (1980) had participants read sentences and make recognition judgments to probes presented immediately after the anaphor words. The results showed more priming for appropriate referents (e.g., burglar) than for other terms within the text that were not candidate referents (e.g., cat). Further research has shown this to be a robust effect, even when controlling for factors such as semantic similarity (O'Brien, Duffy, & Myers, 1986), word length and frequency (Dell, McKoon, & Ratcliff, 1983), and backward inferencing strategies (O'Brien, 1987). An anaphoric inferencing task was chosen for the current research because establishing coreference is basic to a text's coherence (Garnham, Oakhill, & Johnson-Laird, 1982) and reliably occurs during the course of comprehension (Graesser, Singer, & Trabasso, 1994). Ideally, corrected would not interfere with such a fundamental process. One potential difference between an account containing corrected and one that presents only correct information is in the number of candidate referents a subsequent anaphor has. For example, a no-rnisinformation story may correctly identify a prison escapee as a burglar and make a later anaphoric reference to the criminal. In this case, determining the proper referent should be reasonably straightforward. However, in a story containing corrected, the escapee may initially be identified as a forger, and only later correctly identified as a burglar. In this case, a later reference to the criminal would have two semantic ally-related possible referents, although the context would indicate that the former should be excluded as a candidate. Prior research on texts without has found that participants can activate multiple candidate referents (Corbett & Chang, 1983; O'Brien, Albrecht, Hakala, & Rizzella, 1995; O'Brien, Plewes, & Albrecht, 1990) and 1483

2 1484 JOHNSON AND SEIFERT that appropriate referents show less priming when the text contains multiple possible referents (Corbett, 1984). In stories with corrected, the effective number of candidate referents may depend on how well people can ignore the. Some research on directed forgetting (Basden, Basden, & Gargano, 1993; Bjork & Bjork, 1996; Geiselman, Bjork, & Fishman, 1983) and on text comprehension (Gernsbacher & Faust, 1991; Hasher, Quig, & May, 1997) has proposed that people can inhibit or suppress information that is no longer relevant. If people can successfully inhibit, in the ideal case it would be as though the had not been presented at all, and the passage would effectively contain only one candidate referent. In this case, people should have no difficulty accessing the appropriate referent once they read the anaphor. On the other hand, if people still retain corrected as a candidate referent, attempts to resolve a later anaphor could lead them to activate it, as well as the correct referent. This would be consistent with a resonance process (O'Brien et al., 1995), in which a parallel search leads to activation of any candidate referents that have sufficient featural overlap with the anaphor. In this case, people may still activate itself as a candidate rather than treating it as unrelated to the anaphor. They may also show less priming for an anaphor's appropriate referent, relative to a case in which only the correct information is provided. Another potential difference between accounts containing corrected and those without is the relative importance of that initial information. In the prison escape example above, the identity of the escapee is a key component in the story and could influence a number of inferences, including what the escapee's goals and likely actions are and how people will react emotionally to the news. In texts that do not contain, anaphoric referents show more activation when they are involved in more causal connections in the text (O'Brien & Albrecht, 1991; O'Brien & Myers, 1987) or are given more elaboration (O'Brien et al., 1990). Gernsbacher and associates (Gernsbacher & Hargreaves, 1988; Gernsbacher, Hargreaves, & Beeman, 1989) found more activation for information mentioned first in a set of sentences and argued that people use initial information to anchor the representations they are constructing. If people have used to anchor their representations or have involved it in inferential connections or elaborations, its status as a referent again may depend on how well people can ignore it when it is corrected. If the correction leads people to view the as unimportant, it may show activation similar to that of other mentioned but causally unimportant information. On the other hand, it may continue to retain more importance than information incidentally presented in the same position within a story. Finally, the typical recency structure of an account containing corrected could also affect the relative priming levels of earlier information. In normal correction contexts, is presented initially and the correction necessarily follows it at some delay. Thus, when people read a postcorrection anaphor, correcting information will have occurred more recently than. In texts that do not contain, several researchers (Cirilo, 1981; O'Brien, 1987; O'Brien, Shank, Myers, & Rayner, 1988) have found recency effects when experiments controlled for the referent's importance. All else being equal, this leads to the prediction that the more recent, correcting information will be favored and will show more activation than earlier. An additional objective of the current experiments was to determine whether influence from could be understood in a discourse-processing context, and whether it would be evident when on-line measures were used. Prior studies of influence from (Johnson & Seifert, 1994; Schul & Burnstein, 1985; Thompson et al., 1981; Wilkes & Leatherbarrow, 1988; Wyer & Budesheim, 1987; Wyer & Unverzagt, 1985) have typically relied on postcomprehension judgments, rather than on on-line measures, as a basis for hypotheses about what occurs when people are asked to disregard. Analyzing this issue as a case of discourse comprehension would allow us to apply what is already known about inferencing processes to accounts containing. A systematic analysis of how such accounts differ from those that do not contain could help identify the factors that could lead to influence people's inferences. A second benefit would be to make use of on-line methodology to investigate the comprehension processes involved more directly. This strategy could potentially provide more immediate evidence on how and when influences inferences. In the experiments, we compared priming of appropriate and inappropriate anaphoric referents in corrected- story versions with priming of those same referents in no- story versions. This control condition was chosen because numerous prior studies have used it as a standard for determining influence (Johnson & Seifert, 1994; Schul & Burnstein, 1985; Thompson et al., 1981; Wilkes & Leatherbarrow, 1988; Wyer & Budesheim, 1987; Wyer & Unverzagt, 1985) and because a communicator who corrects typically intends that people disregard it and understand the account as though only the correct information had been presented. We hypothesized that if participants did disregard corrected successfully, appropriate referents would show similar priming in both types of stories. On the other hand, if participants were not entirely successful, we predicted less priming for the appropriate referent in the corrected- condition because the might still act as a candidate antecedent. Participants could also show more priming of the inappropriate referent in the corrected- condition than in the no condition because the could retain more importance than incidentally mentioned information. In Experiment 1, test probes were presented at a 300-ms delay after the anaphor to minimize the influence of context-checking strategies (McKoon & Ratcliff, 1990). In Experiments 2A and 2B, the probe onset was delayed to 850 ms and 1,200 ms, respectively, to determine whether activa-

3 UPDATING AFTER CORRECTIONS 1485 tion of referents changes over time, as found in a number of studies (Gemsbacher & Faust, 1991; Swinney, 1979). Method Experiment 1 Participants. The participants were 58 University of Michigan undergraduates who received course credit in introductory psychology for taking part in the experiment. Participants were tested in groups of three, in single sessions lasting approximately 50 min. Design and materials. The design was a 2 X 2 within-subjects factorial, with story (corrected, no ) and probe (appropriate, inappropriate) as variables. The materials consisted of 38 stories, styled after news events, on a wide variety of topics. The stories provided naturalistic information about complex events, with content that could plausibly be corrected. They were structured to present facts in a roughly chronological order of discovery. Each story was 15 sentences long. For each of 35 target stories, a no- control and a corrected- version were constructed (see Appendix A). In both story versions, Line 12 made an anaphoric reference to target information presented earlier in the story (Line 8). Line 8 was also the same in both story versions and presented an appropriate referent (i.e., the "correct" fact) for the anaphor in Line 12. In both story versions, Line 4 presented an inappropriate referent for the anaphor in Line 12. In corrected- story versions, the referent was inappropriate because it was that Line 8 corrected. In no- story versions, the referent in Line 4 was inappropriate because it was incidentally mentioned, and the story context did not lead participants to see the anaphor as mapping onto it. For example, in a story about a missing child, the anaphor sentence mentioned the kidnapper, where kidnapper referred back only to the person who had abducted the child and not to another person who was mentioned earlier. Three additional practice stories had only no- versions. The information in Line 8 was presented in the form of a strong exclusionary statement (e.g., now shown that only Y is true) in both the corrected- and no- story versions. This format was used rather than a statement of the form not X, Y to control for recency and number of mentions of the inappropriate probe in the corrected- story versions. To increase the likelihood that the Line 8 statements would be interpreted as corrections, the statements used strong exclusionary terms like only, temporal" terms (e.g., now) to indicate that an update was occurring, and verbs that expressed certainty (e.g., shown, proved, concluded). Context in adjacent story lines also provided justification for Line 8 statements. Appendix B shows examples of statements and later exclusionary statements. A set of validation tasks was used to determine how participants understood such exclusionary statements. In the first task, participants read story packets that contained corrected-mismformation and no- story versions, placed in random order. Story version was counterbalanced across participants. After each story page in the packet, a question page asked four questions about each story. For each story, one of the questions explicitly asked participants to make the anaphoric inference required in the anaphor sentence (e.g., Who is the girl's kidnapper?). A materials analysis of 11 participants' responses showed a significant main effect of probe, F(1, 27) = , p =.0001, MSE = 7.29, and a significant interaction of Probe X Story, F(l, 27) = 8.29, p =.008, MSE = 2.69 (see Table 1). These results suggested that a large Table 1 Average Number of Appropriate and Inappropriate Responses per Story Version Probe type Inappropriate Appropriate Inappropriate Appropriate Corrected Validation task Corrected Validation task Story type No Contradiction majority of participants accepted the information in the exclusionary statement as the appropriate referent. Few endorsed the inappropriate referent in either story version, although this was more likely to occur when was corrected. This contrasts with the results from the second validation task, which used the same procedure but compared the exclusionary statements with ones that were intentionally more ambiguous. To create the latter, the statements in Line 8 were modified so they used hedged verbs and did not include exclusionary terms like only (e.g., now suggested that Y might be true). If participants perceived the exclusionary statements as ambiguous contradictions, one would expect similar answer patterns for both types of statements. However, in a materials analysis of 13 participants' responses, the results showed a significant main effect of probe, F(l, 27) = 10.53, p =.003, MSE = 15.23, but this was qualified by a significant interaction of Probe X Story, F(l, 27) ,/? =.002, MSE = 8.75 (see Table 1). These results showed that participants were more likely to take the exclusionary statements as ruling out the earlier information rather than simply presenting contradictory information. On the basis of these two tasks, the participants appeared to understand the materials as intended for the purposes of the experimental design. Each of the 35 target stories had an appropriate and inappropriate probe associated with it. For each story, target-probe words were equated for word frequency, length, and plausibility as a correct referent within the given story structure. Random assignment was used to determine which probe would be used as an appropriate or inappropriate referent in each story. For the kidnapping story shown in Appendix A, the appropriate and inappropriate probes used were coach and widow, respectively. For each story, an additional probe was chosen for use as a distractor. It was equated with the pair of target probes in length, word frequency, and part of speech, but it did not appear in any of the stories in the corpus. Four story presentation lists were created. Each list consisted of 3 practice stories and 35 target stories. The target stories appeared in a single random order in all four lists, with the constraint that no more than 3 corrected- or no- stories appeared in a row. Within the first list, the target stories were randomly assigned to serve as either corrected- stories (14), no- stories (14), or distractors (7). Then, within both of the story conditions, participants were tested with seven inappropriate referents and seven appropriate referents, each appearing as the first probe presented immediately after the anaphor sentence. Within the remaining three lists, story type and probe type were rotated so they were counterbalanced across

4 1486 JOHNSON AND SEIFERT participants. Thus, each story appeared in both corrected and no- versions and was tested with both appropriate and inappropriate probes. The distractor stories within a list were also divided into corrected- and no- versions but were always tested with distractor probes. Story version for distractor stories was also rotated across the four lists. Three other distractor probes followed the target probe during each speeded-recognition test sequence. For the 28 correction and control stories, additional probes were chosen so that for 14 of the stories, two probe items came from the current story and two did not (target probes were included in this count); for 7 of the stories, three probes came from the current story and one did not; for the remaining 7 stories, one probe came from the current story and three did not. Which stories conformed to which pattern of recognition probe items was determined at random. The probes were also balanced so that for each ordinal position two through four, true and false answers occurred equally often. True distractor probes always appeared before Line 12 in the designated story and in no others in the corpus. False distractor probes were paired with items in the story and matched for word frequency, length, and part of speech, but they did not occur in any of the stories in the corpus. In addition, two true-false comprehension items were constructed for each story. True items were lines taken directly from the story, whereas parallel false items were created by altering each line to assert a fact plausible given the story's general topic but inconsistent with or introducing content that was not present in the story context. Lines 4 and 8, which introduced the target probe alternatives, were never used as comprehension test items. The presentation order of the items, as well as whether they were true or false, was chosen randomly, with the constraint that each possible response pattern (true-true, true-false, etc.) occurred equally often across the entire set of stories. Procedure. All materials were presented using the Micro Experimental Laboratory (MEL; Schneider, 1988) program on a Zenith computer (PC clone using a DOS operating system), and all responses were made via keyboard. Participants completed two training sets, designed to familiarize them with reaction time tasks. On each of 20 trials, a??????? warning cue appeared for 300 ms, automatically succeeded by a test word. If the word contained an E, participants were to press the j key with the right index finger; if the word did not contain an E, they pressed the/key with the left index finger. A ** deadline warning symbol appeared underneath each test item after 650 ms had elapsed. If participants responded in under 650 ms, the deadline symbol did not appear, and instead a warning for the next test item would appear. If participants did not respond within 2,000 ms, the trial was scored as an error, and a warning for the next word would appear automatically. Participants were told that the ** deadline symbol was to encourage them to respond quickly and that they should try to respond before it appeared. Participants received both error feedback and reaction time feedback during the training series. In the next phase, participants were told they would be doing two different tasks. One task was to read carefully, and try to comprehend, a series of stories based on live-on-the-scene news reports, to answer test questions after each story. Participants were not expressly warned that some of the stories contained corrections. The second task was to verify whether probe words presented during the story had appeared earlier in the story. The stories appeared sentence by sentence, with self-paced presentation. Participants pressed a key to advance the screen, replacing the current sentence with the next. If participants did not advance the screen within 10 s, the next line appeared automatically. After presentation of the anaphor sentence in each story, the participants saw a??????? cue, which appeared for 300 ms. The first word in each probe series was either the inappropriate referent, presented in Line 4, or the appropriate referent, presented in Line 8, for the story currently being read. The participants pressed they key if the word did appear in the current story or the / key if it did not. This probe-recognition task involved the same speeded-recognition procedure and instructions as in the training series, except that participants received no reaction time feedback. Each probe series also included three additional recognition probes, presented with the format described earlier. After the probe-recognition series, participants did self-paced reading of several more lines from the same story. They then answered two true-false questions about the preceding story, pressing they key for a true statement and the/key for a false one. Participants were told that this task would not be timed and that they should take as long as they needed to answer the questions accurately. Participants did 3 practice stories before beginning the 35 target stories. Results The mean verification times for all target-probe words were recorded. Response times that were more than 2.5 SDs from the overall mean ( ms) were discarded. Participants who scored less than 75% on the true-false comprehension items were eliminated from the analyses so the inference results would be based on participants who had read and understood the texts. Further, only participants with five or more observations per cell were included to have more stable measures of average reaction time. The number of trimmed reaction times was analyzed in a 2 X 2 analysis of variance (ANOVA), with story (corrected, no ) and probe (appropriate, inappropriate) as variables and subjects as a random variable; the analysis was not significant (Fs < 1.7). The reaction time trim eliminated 2.5% of the trials. An alpha level of.05 was used for all statistical tests. Reaction times for correct responses were analyzed in 2 X 2 ANOVAs, with story (corrected, no ) and probe (appropriate, inappropriate) as variables, using both subjects and materials as random variables. The pattern of results can be seen in Figure 1. The results showed a significant main effect of probe with both subjects and materials as random variables, min F'(l, 52) = 18.34, p =.01, with faster times for appropriate probes. The main effect of story was not significant (Fs < 1.1). The results also showed a significant interaction of Story X Probe under a subjects analysis, F(l, 51) = 7.08, MSE = 2,328.01, p =.01. A materials analysis showed the same pattern of results, with a trend toward significance, F(l, 27) = 2.94, MSE = 3,321.69, p.098. Planned comparisons showed that participants responded significantly faster to appropriate probes in the no- stories than in corrected stories, F(l, 51) = 7.03, MSE - 3,821.38, p =.011; F(l, 27) = 4.29, MSE - 3,844.14,/? -.048, under subjects and materials analyses, respectively. A planned comparison of responses to inappropriate probes for the two story types was not significant (Fs < 1). The number of inaccurate responses was also analyzed in a 2 X 2 ANOVA, with story and probe as variables, for both

5 UPDATING AFTER CORRECTIONS T H O Appropriate no corrected Probe Type Inappropriate Figure 1. Recognition times at a 300-ms delay, by story type and probe type, in Experiment 1. subjects and materials. The proportions are reported in Table 2. The results showed a significant main effect of probe with subjects and materials as random variables, min F'(l, 42) = 6.88, p =.025, with more errors on inappropriate than on appropriate probes. The interaction of Probe X Story was not significant (Fs < 2.9). A Pearson's correlation between reaction times and number of errors for all four conditions showed no evidence of a speed-accuracy trade-off (r =.11, p >.05). When just the appropriate probes in the two story conditions were considered, a Pearson's correlation between reaction times and errors was.123 (p >.05). Scores on other performance measures were also computed. Participants showed a mean of 90% correct on the comprehension items. There were no significant differences in comprehension scores for the different conditions under a subjects analysis (Fs < 1.2). Participants also correctly identified 81% of the total recognition items. Reading time Table 2 Mean Proportion of Inaccurate Responses in Experiment 1 Probe type Inappropriate Appropriate Corrected Story type No analyses for the exclusionary statement (Line 8) and for the anaphor statement (Line 12) were not significant (Fs < 1.2). Discussion The results provide evidence that corrected can influence people's on-line comprehension when they need to make anaphoric inferences. Participants showed significantly less activation for appropriate referents that were corrections of. Prior work (Corbett, 1984; O'Brien et al., 1995) has found less activation for an anaphoric referent when a passage contained an additional candidate referent. The finding in the current study suggests that the remains a candidate antecedent, despite the presence of a strong exclusionary statement that indicates it is incorrect. This, in turn, suggests that participants may have more difficulty accessing and using a correct referent in inferences when has been presented. However, the priming responses and error rates for inappropriate referents did not significantly differ, whether they were corrected or information incidentally mentioned at the same point in the story version. Prior research (O'Brien & Albrecht, 1991; O'Brien & Myers, 1987) has found more priming for information when it is more causally related or rated as more important. This suggests that, at a short delay, and incidental information have similar importance and memorability in the account. Finally, the relative activation of appropriate and inappropriate probes was consistent with prior findings of recency effects in anaphoric reference (Cirilo, 1981; O'Brien, 1987). The recency difference in the current experiments does not allow conclusions about absolute activation levels of and correcting information; however, the results do represent what would occur in a typical correction situation. Correcting information necessarily follows the it corrects, so it will necessarily be more recent and thus may have a quite natural activation advantage when people try to comprehend postcorrection anaphors. More generally, the current results suggest that investigating effects in terms of discourse processing has potential benefits for understanding them. First, this approach allows for a systematic, rather than a post hoc, analysis of potential factors that could infiuence comprehension when is present. It also allows for predictions about the consequences of successfully disregarding, which in turn can shed light on the processes people use to deal with it. Finally, use of on-line methodology can provide more direct evidence on how and correcting information may influence people during the comprehension process. The finding of no significant reading-time differences could have occurred for a number of reasons. First, the exclusionary statement in corrected- story versions introduced the correction, whereas in no- story versions, this line was a first mention of that information. Both inference difficulty and first mention can increase reading times, so it is unclear which of these two would be predicted to be longer. Second, reading times for

6 1488 JOHNSON AND SEIFERT the anaphor sentence might not be sensitive to the difference in recency of the appropriate and inappropriate information. In essence, recency is controlled because every story version had an appropriate referent in Line 8. Therefore, reading times would not necessarily be longer in the corrected conditions just because appeared earlier in the story. The current results are unlikely to have occurred because of item effects. First, each of the target stories had a corrected- and a no- version. Probe type was counterbalanced across participants, so each story version was tested with both an appropriate and an inappropriate probe. Thus, the results do not reflect differences in story content across the conditions. Second, the same words were used as appropriate probes in the two story conditions, so item differences cannot account for the response time differences that were found. (Similarly, the same words were used as inappropriate probes in the two story conditions.) The story versions did use different words as the appropriate and inappropriate probes, but the probes for each story were matched on length, familiarity, and plausibility within the story, and then randomly assigned a position in either Line 4 or Line 8 of the story. This should minimize the contribution that item effects make to the response time difference between appropriate and inappropriate probes. There are also reasons to believe that the results are not simply due to participants' failing to believe or understand the exclusionary statements. First, if participants believe the is the appropriate referent, they should make faster responses to inappropriate probes in the corrected- story versions than in the no versions. However, the difference between inappropriate probes in the two story conditions was not significant. Second, the results from the materials validation tasks show that participants do not interpret the exclusionary statements used here as fundamentally ambiguous, although they are not as clear as when presented in stories without. In summary, the results show that corrected can influence participants shortly after they read an anaphor. One can then ask whether this activation pattern remains stable over longer delays. On one hand, prior research on resolution of ambiguous words (Gernsbacher & Faust, 1991;Swinney, 1979)andof anaphors (O'Brienetal., 1995) has found that initial activation of contextually irrelevant information decreases over time, whereas that of contextually relevant information stays stable or increases (Gernsbacher & Faust, 1991; O'Brien et al., 1995). If such processes occur when participants read postcorrection anaphors, they could potentially overcome any initial influence from. On the other hand, if participants are simply more uncertain about the appropriate referent in corrected- stories, they may not be able to resolve the uncertainty, even with additional processing time. In this case, one might expect responses to the appropriate referent in corrected- story versions to continue to be slower than those made when a story does not contain. Experiment 2 In Experiment 2, we tested whether activation levels for appropriate and inappropriate referents change over time, after participants have read a postcorrection anaphor. As in Experiment 1, participants read corrected- and no- story versions and performed speeded-recognition tests on appropriate and inappropriate probes. In Experiment 2A, the delay between anaphor offset and test-probe onset was either 300 ms or 850 ms, and in Experiment 2B, the delay was 1,200 ms. Previous research (Gernsbacher, 1990) has suggested that activation changes would have occurred by 800-1,200 ms after anaphor offset. The short-delay condition should replicate the findings in Experiment 1, in which appropriate referents showed less activation in corrected- than in no- story versions. If participants could overcome initial difficulty in activating a referent, one would expect appropriate information to show similar levels of activation in the 850-ms delay condition, regardless of whether the story version contained corrected or not. On the other hand, if participants were uncertain about the appropriate referents in corrected- story versions, one would expect their activation to remain less man that of the same referents in the no- story versions. The longer delay condition in Experiment 2B would provide additional time for activation of inappropriate information to decrease and could reveal whether was more likely to retain activation than merely incidental information. The results from Experiments 2A and 2B are analyzed separately because they were conducted at different times. Method Experiment 2A Participants. The participants were 120 University of Michigan undergraduates who received credit in introductory psychology for taking part in the experiment. Participants were tested in groups of three. Design. The design was a 2 X 2 X 2 factorial, with delay (short, intermediate), probe (appropriate, inappropriate), and story (corrected, no ) as variables. Probe and story were manipulated within subjects, as in Experiment 1, and delay was added as a between-subjects variable. In the intermediate-delay condition, the interval between the anaphor sentence offset and the probe onset was 850 ms. In the short-delay condition, this interval was 300 ms. Materials and procedure. The materials and procedure were the same as in Experiment 1. Results The same data-trim criteria were used as in Experiment 1. Within this pool, reaction times were eliminated if shorter than 300 ms or greater than 2.5 SDs above the overall mean (670 ms). The reaction time trim eliminated 3% of the observations. An analysis of the number of reaction times trimmed from each condition showed no significant effects (Fs < 2.3).

7 UPDATING AFTER CORRECTIONS 1489 Reaction times for correct responses were analyzed in 2 X 2 X 2 ANOVAs, with story (corrected, no ), probe (appropriate, inappropriate), and delay (short, intermediate) as variables, using subjects and materials as random variables. The pattern of results can be seen in Figure 2. There was a significant main effect of probe under subjects and materials analyses, min F'(l, 40) = 25.39, p =.01. Participants responded faster to appropriate than to inappropriate probes. When reaction times were analyzed with materials as a random variable, there was a significant main effect of delay, F(l, 27) = 13.70, MSE 1,591.26, p =.001, with responses being faster in the intermediate-delay condition. This was not significant in a subjects analysis (F < 1.34). The main effect of story was not significant in either analysis (Fs < 1). In addition, an analysis of reaction times showed a significant interaction of story and probe under a subjects analysis, F(l, 118) = 5.57, MSE = , p =.02, and with materials as a random variable, F(l, 27) = 6.23, MSE = , p =.019. Planned comparisons showed a significant difference between appropriate probes in the no- and corrected- conditions in the short-delay condition, F(l, 59) = 6.17, MSE = 2,562.93, p =.016; F(l, 27) = 3.36, MSE = 2,041.70, p =.078, under subjects and materials analyses, respectively. This comparison was not significant in the intermediatedelay condition (Fs < 1). However, planned comparisons showed a significant difference between inappropriate probes D control-appropriate corrected-appropriate 0 control-inappropriate Q corrected-inappropriate in the no- and corrected- conditions in the intermediate-delay condition, F(l, 59) = 4.24, MSE = 5,987.53, p =.044; F(l, 27) = 6.78, MSE = 2,601.74, p =.015. This comparison was not significant in the short-delay condition (Fs < 1). The results of subjects and materials analyses also showed a significant interaction of Story X Delay, F(l, 118) = 4.84, MSE = 2,261.67, p =.03, and F(l, 27) = 5.64, MSE = , p =.025, respectively. Planned comparisons of reaction times to appropriate corrected- story probes by delay showed a significant difference under both subjects and materials analyses, *(118) = 2.18, p.031; t(21) = 4.23, p =.0001, respectively. The difference in reaction times to inappropriate corrected- story probes by delay was significant in a materials analysis, f(27) = 2.67, p =.013, as was the difference between no- story probes by delay, f(27) = 2.25, p =.033. Neither of these analyses was significant under subjects analysis, (t < 1.14). No other interactions in the 2 X 2 X 2 reaction time analysis were significant (Fs< 1.5). The number of inaccurate responses was analyzed in 2 X 2X2 ANOVAs, with story, probe, and delay as variables for both subjects and materials. The proportions are reported in Table 3. The results showed a significant main effect of probe, with subjects and materials as random variables, min F'(l, 61) = 14.37,/? =.01, with more errors for inappropriate probes. The results also showed a significant interaction of Probe X Delay in a subjects analysis, F(l, 118) = 3.92, MSE= 0.511, p.05, and also in a materials analysis, F(l, 27) = 4.52, MSE = 1.708, p =.043. Participants in the intermediate-delay condition had fewer errors in the appropriate probe conditions and more in the inappropriate probe conditions. No other main effects or interactions were significant (Fs < 2.8). Participants were correct, on average, on 91% of the true-false items. There was a significant main effect of delay, F(l, 118) = 8.09, MSE = 0.01, p =.005, with participants showing a higher proportion of correct items in the intermediate-delay condition (M =.92) than in the short-delay condition (M =.90). Participants correctly identified 83% of the total recognition items. Analyses of reading times for the exclusionary statement (Line 8) and the anaphor sentence (Line 12) showed no significant effects (Fs< 1.9). 300 ms 850 ms Delay Figure 2. Recognition times at 300-ms and 850-ms delays, by story type, probe type, and delay, in Experiment 2A. Method Experiment 2B Participants. The participants were 68 University of Michigan undergraduates who received credit in introductory psychology for taking part in the experiment. Participants were tested in groups of three. Design. The design was the same as in Experiment 1, but the interval between the anaphor sentence offset and the probe onset was increased to 1,200 ms. Materials and procedure. The materials and procedure were the same as in Experiment 1.

8 1490 JOHNSON AND SEIFERT Table 3 Mean Proportion of Inaccurate Responses in Experiment 2A Probe type Inappropriate Appropriate Corrected Short delay No Corrected Long delay No Results The same data-trim criteria were used as in the previous experiments. Trials were eliminated if shorter than 300 ms or greater than 2.5 SDs from the mean (670 ms). The reaction time trim eliminated 2.7% of the observations. Analyses of the number of reaction times trimmed from each condition showed no significant differences (Fs < 1). Reaction times for correct responses were analyzed in 2 X 2 ANOVAs, with story (corrected, no ) and probe (appropriate, inappropriate) as variables, using subjects and materials as random variables. See Figure 3. Both subjects and materials analyses showed a significant main effect of probe, min F'(l, 48) = 12.08,/? =.01, with shorter reaction times for appropriate probes. The main effect of story was not significant (Fs < 1.3). A significant interaction of Story X Probe also occurred, min F'(l, 66) = 4.09, p =.05. Planned comparisons showed a no corrected significant difference in reaction times for inappropriate probes in the two story conditions, F(l, 67) = 7.98, MSE = 5,054.55, p =.006; F(l, 27) = 4.07, MSE = 4,270.70, p =.054, under subjects and materials analyses, respectively. The number of inaccurate responses was analyzed in 2 X 2 ANOVAs, with story and probe as variables for both subjects and materials. The proportions are reported in Table 4. The results showed a significant main effect of probe with subjects and materials as random variables, min F'(l, 49) = 12.28, p =.01. Participants made more errors on inappropriate probes. There was no significant main effect of story or interaction of Probe X Story (Fs < 1.5). Participants were correct on a mean of 91% of the true-false items. However, analyses of Experiment 2B showed a small but significant main effect of probe on comprehension scores, under a subjects analysis, F(l, 67) = 4.04, MSE = 0.006, p =.048, with higher scores when the appropriate probe was presented (M =.92) than when the inappropriate probe was presented (M.90). Participants correctly identified 83% of the total recognition items. Analyses of the reading times for the exclusionary statement (Line 8) and the anaphor sentence (Line 12) showed no significant effects (Fs < 1.7). Discussion The results show different patterns of activation with increased delay. As in Experiment 1, appropriate referents in corrected- story versions showed significantly less activation than those in no- story versions at a 300-ms delay. However, this difference was not significant in the longer delay conditions. This suggests that after additional processing time, the availability of appropriate referents presented as corrections is comparable with that of referents provided in stories without. On the other hand, the inappropriate referents in the two story versions did not show significant differences in activation at a 300-ms delay. As delay increased, these levels diverged so Appropriate Inappropriate Probe Type Figure 3. Recognition times at a 1,200-ms delay, by story type and probe type, in Experiment 2B. Table 4 Mean Proportion of Inaccurate Responses in Experiment 2B Probe type Inappropriate Appropriate Corrected Story type No

9 UPDATING AFTER CORRECTIONS 1491 that inappropriate referents in corrected- story versions showed significantly more activation than those in no- story versions. This suggests that and incidental information do not retain a similar status within people's text representations. The change in pattern could have occurred for a number of reasons. One possibility is that appropriate referents in corrected- stories increase in activation through a process of enhancement. Gernsbacher and Faust (1991) found increased activation of appropriate anaphoric referents and context-appropriate associations in materials that did not involve corrections. They proposed that enhancement helps people make inferences by using relevant, rather than irrelevant, information. They also proposed a companion process, suppression, that would decrease activation of irrelevant information. However, the current results do not show evidence of this; one would expect both and incidental information to be suppressed at an equal rate. Another possible explanation is that participants make strategic inferences to try to resolve uncertainty about the appropriate referent in corrected- story versions. They may ask themselves whether this is correct and attempt to verify this by thinking back on the story. When they recall the, they can make a decision that the correcting information is valid. This search may have the side effect of increasing activation of the as well. The results cannot be accounted for by overall facilitation due to the delay. First, one could argue that participants in the intermediate- and long-delay conditions could respond more quickly because they could ready their motor responses before the probe appeared. For participants in the short-delay condition, readying the response could account for part of the response time. One would expect differences in motor readiness to affect responses in all four probe conditions. However, only the probes in the corrected story versions showed faster reaction times with the longer delay. Times in the no- conditions were not significantly different from those that occurred at a short delay. This is inconsistent with a general delay advantage explanation. The results are also inconsistent with the argument that participants viewed the corrected- story versions as fundamentally ambiguous. If participants were unable to determine which probe was appropriate, one might expect a significant difference between appropriate probes in the two story conditions to occur at each delay period; however, this difference was only significant in the shortest delay condition. This suggests that participants for the most part can resolve whatever initial ambiguity might exist, so the presence of does not have a lingering effect on the activation of the appropriate referent in a corrected- story version. General Discussion The current results suggest that influence from corrected can occur during the process of comprehending a subsequent anaphoric reference. In Experiment 1, participants showed significantly less activation for appropriate referents when the referents were corrections of. Prior research (Corbett, 1984) has found that participants activate an anaphor's referent more slowly when there are other candidate referents in the passage. The results of Experiment 1 suggest that retains status as a candidate antecedent, despite indications that it should be disregarded. This would be consistent with a resonance process (O'Brien et al., 1995) in which a candidate referent's predisposition to be reactivated (resonance) depends more on its recency, elaboration, and degree of featural overlap with an anaphor and less on contextual cues about its relevance. Resonance based on such factors may not change when is corrected and the story context indicates that it is an inappropriate referent. The current findings would be inconsistent with a number of proposals that people inhibit information that is no longer relevant (Basden et al., 1993; Geiselman et al., 1983; Hasher et al., 1997). The results also suggest that may remain more important within a representation than incidental information presented in a similar position in the story. Experiment 2B showed that had significantly more activation than incidental information at a 1,200-ms delay from anaphor offset. Prior studies using texts without have found more priming (O'Brien & Albrecht, 1991; O'Brien & Myers, 1987) for information rated as more important. One could argue that these results occur because participants find correction stories ambiguous or just "harder to understand," but it would also be important to consider the nature of the difficulty. If participants perceive the correcting statement as a mere contradiction of earlier information, they might tend to discount it in favor of the initial information provided. However, if the initial information were considered more important, one would expect it to be more activated than the correcting information, despite its being less recent. O'Brien and associates (O'Brien, 1987; O'Brien et al., 1990) found that recency effects broke down when earlier information was more important than later information. Also, the validation tasks in the current experiments show that participants found the exclusionary statements used as corrections less ambiguous than contradiction statements that were less strongly worded. Further, if participants consistently activated the on reading the anaphor statements, one would expect some evidence of this when inappropriate probes from corrected stories are tested at a short delay; however, this did not occur. Finally, if participants found the corrections fundamentally ambiguous, one might expect this to be a lasting effect rather than one that changes with increased processing time. These findings suggest that corrections are harder to understand because of textual properties rather than because of a fundamental ambiguity. The current results build on prior work on effects in several ways. First, they provide more direct evidence that influence from can arise on-line during the course of comprehension. A number of prior investigators have proposed that influence occurs as

10 1492 JOHNSON AND SEIFERT people build a representation (Johnson & Seifert, 1994; Ross et al., 1975; Wilkes & Leatherbarrow, 1988; Wyer & Budesheim, 1987), but the postcomprehension measures typically used cannot discriminate this from the case in which influence arises after comprehension, at the time a judgment is requested. Second, the results show that current knowledge on discourse processing can lead to systematic predictions on how and when might influence people's understanding. Few studies have assessed priming when information is discontinued. MacDonald and Just (1989) had participants read statements containing negations, such as "Martha bought cookies, not bread at the store," and then do a lexical-decision task, after each statement. The results showed less priming when items were negated than when they were not. However, in this case the negation functions to exclude one of two options rather than as a correction of information asserted earlier. Klin and Myers (1993) also found evidence that participants did not reactivate disconfirmed causes when making inferences later in a text. However, this study involved providing information that disconfirmed an earlier expectation rather than information that explicitly corrected something directly asserted earlier. The results also build on what is known about updating processes in discourse comprehension. Several researchers (Garrod & Sanford, 1990; Gernsbacher, 1990; Glenberg & Langston, 1992) have characterized updating processes in terms of foregrounding information that is relevant to current comprehension and backgrounding what is less relevant. For example, people may foreground information about a protagonist's character (Albrecht & O'Brien, 1993), emotions (Gernsbacher, Goldsmith, & Robertson, 1992; Gernsbacher & Robertson, 1992), or location (de Vega, 1995; O'Brien & Albrecht, 1992) when this is relevant to understanding current information. On the other hand, information about other characters, past locations, or irrelevant semantic associations (Gernsbacher & Faust, 1991) can be backgrounded. In each of these cases, the information is not currently focal but should retain some status within the representation because it may be needed for later comprehension. Updating after is corrected is a more extreme case because if the is truly wrong or unfounded, it should be backgrounded and remain so, if it cannot be eliminated completely. It may be the case that the updating that follows corrected occurs according to general updating principles, but the answers to this are worth empirical investigation rather than being foregone conclusions. The current studies address factors that would typically differentiate accounts containing from those that do not, but they also suggest ways to further clarify the activation of and correcting information in more absolute terms. In the current studies, we used the no- control as a lower baseline to determine whether was having an influence. This has been the standard control in numerous studies involving (Johnson & Seifert, 1994; Schul & Burnstein, 1985; Thompson et al., 1981; Wilkes & Leatherbarrow, 1988; Wyer & Budesheim, 1987; Wyer & Unverzagt, 1985) and seems natural in terms of the ideal goal of correction to have people comprehend the account as if no had been presented. However, it would also be possible to compare corrected- story versions with stories that contain multiple candidate antecedents but no instructions to disregard any of them. This would provide an upper bound and allow investigators to determine whether a correction has any effect on the tendency to view corrected as a candidate referent. Further research could also address the source of the activation differences between and correcting information in more detail. In the current studies, we presented early in the story to control for the recency of the appropriate referent in bom story conditions and to make the stories as similar as possible but for the. Again, this approximates the time course that would naturally occur in a correction situation correcting information is necessarily more recent than the it corrects. It would be possible to investigate the contribution of recency more fully by comparing story versions that contain initial with those that present only correct information at the same place in the story or by varying the relative lags between and the test anaphor. However, these manipulations may shed little practical light on comprehension of naturally occurring corrections, in which the correcting information may be provided hours or days after the. Response competition could also contribute to the difference in activation between and correcting information but would not compromise the main claims made here about influence from. The speeded-recognition task used in these studies involves verifying that a probe item was present within the passage rather than whether it is the correct referent for the anaphor just presented. However, one could argue that, nevertheless, the issue of correctness or relatedness comes to mind, which would lead to response competition in responses for inappropriate probes but not for appropriate probes. (For appropriate probes, present and related are both yes; for inappropriate probes, present is yes but related is no.) One way to overcome this would be to use a naming procedure (Potts, Keenan, & Golding, 1988) rather than speeded recognition. However, this article's main claims of influence are based on comparisons between either the appropriate probes in the two story conditions or the inappropriate probes in the two story conditions. Response competition would not account for these differences. In summary, the results show that influence from, in the sense of alteration of comprehension processes, can occur as participants make inferences after a correction. The results also suggest that current knowledge about comprehension can be used to analyze accounts containing and make testable predictions about how people understand corrections and when influence is likely to occur. Finally, the current results show that on-line methodologies can be successfully applied to this problem. This would allow for more precise investigation, not only of how influence arises in inferences and judgments

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