Can suggestions of non-occurrence lead to claims that witnessed events did not happen?

In three experiments, we examined whether general suggestions of non-occurrence -suggestions that experienced events did not occur- would lead participants to claim that events they witnessed never happened. Participants viewed a video depicting the investigation of a child kidnapping case and subsequently were exposed to suggestions of non-occurrence either once (Experiments 1 and 3) or three times (Experiments 2 and 3). The results provided no evidence that single suggestions of non-occurrence influenced participants' memories or belief (Experiments 1 and 3). However, in two experiments (E2 and E3) the results provided clear evidence that repeated elaboration of suggestions of non-occurrence led participants to claim that the events they witnessed never happened. The finding that participants were influenced by repeated, but not single elaboration of suggestions of non-occurrence shows that reflective elaboration processes played an important role in leading participants to disbelieve the events they had witnessed.

Correcting eyewitness suggestibility: does explanatory role predict resistance to correction?

Many studies have documented that exposure to post event misinformation can lead eyewitnesses to misremember witnessing events they did not see and do so with high confidence. The goal of the present study was to investigate whether reporting of suggested misinformation can be reversed following a correction, and if so, whether misinformation would be more resistant to correction when it serves an explanatory function than when it does not. In two experiments participants witnessed an event, were exposed to a blatantly false suggestion(s) and one week later received a correction followed by a test of their memory for the witnessed event. We found evidence for both the persistence of misinformation following a correction (E1) and the complete reversibility of misinformation effects following a highly salient correction (E2). Although false reporting of the misinformation doubled when it served an explanatory function relative to when it did not (E1 and E2), in both experiments we found no evidence that resistance to correction varied as a function of the misinformation's explanatory role. Our findings suggest that, with a salient correction provided by a credible source, people are capable of updating their knowledge with new information that reverses what they previously thought.

Does evaluating belief prior to its retraction influence the efficacy of later corrections?

News stories unfold over time, with initial reports sometimes containing mistaken accounts of the newsworthy outcome that are ultimately revised or corrected. Because facts associated with newsworthy events are accumulated in this piecemeal fashion, readers often have repeated opportunities to reflect upon, discuss, and evaluate their belief in these accounts before they learn that initial news reports have been revised or retracted. The primary goal of the present study was to assess whether rating the strength of one's belief in the initially reported, mistaken cause might influence the efficacy of a later correction. In the current study, participants evaluated their belief in the target cause by either rating how much they believed it caused the outcome (Experiment 1) or rating the probability that the target caused the outcome (Experiment 2). The results showed that evaluating belief in a target cause prior to its retraction (relative to not doing so) rendered the correction more effective. This enhanced correction effect was not observed when participants generated the target information prior to its retraction (Experiment 3). Collectively, the results suggest that it is not how much people believe something, but whether they have thought about why they do or do not believe it, that affects their later willingness to revise their mistaken beliefs.

Mechanisms of eyewitness suggestibility: tests of the explanatory role hypothesis.

In a recent paper, Chrobak and Zaragoza (Journal of Experimental Psychology: General, 142(3), 827-844, 2013) proposed the explanatory role hypothesis, which posits that the likelihood of developing false memories for post-event suggestions is a function of the explanatory function the suggestion serves. In support of this hypothesis, they provided evidence that participant-witnesses were especially likely to develop false memories for their forced fabrications when their fabrications helped to explain outcomes they had witnessed. In three experiments, we test the generality of the explanatory role hypothesis as a mechanism of eyewitness suggestibility by assessing whether this hypothesis can predict suggestibility errors in (a) situations where the post-event suggestions are provided by the experimenter (as opposed to fabricated by the participant), and (b) across a variety of memory measures and measures of recollective experience. In support of the explanatory role hypothesis, participants were more likely to subsequently freely report (E1) and recollect the suggestions as part of the witnessed event (E2, source test) when the post-event suggestion helped to provide a causal explanation for a witnessed outcome than when it did not serve this explanatory role. Participants were also less likely to recollect the suggestions as part of the witnessed event (on measures of subjective experience) when their explanatory strength had been reduced by the presence of an alternative explanation that could explain the same outcome (E3, source test + warning). Collectively, the results provide strong evidence that the search for explanatory coherence influences people's tendency to misremember witnessing events that were only suggested to them.

Belief in corrective feedback for common misconceptions: Implications for knowledge revision.

When correcting a common misconception, it seems likely that for corrective feedback to be effective, it needs to be believed. In 2 experiments, we assessed how participants' belief in the validity of corrective feedback regarding individual misconceptions influenced knowledge revision. After responding about the validity of a set of misconceptions, participants received either a refutation alone (feedback that they were correct or incorrect) or a refutation accompanied by a supporting explanation, and then rated their belief in the corrective feedback. One week later, participants once again responded about the validity of the misconceptions. Across both experiments, participants corrected their misconceptions more often when they believed the corrective feedback. In addition, participants corrected their misconceptions more often when they had earlier received a refutation with a supporting explanation than when they had received the refutation only. This benefit of supportive explanations on knowledge revision was mediated by belief in the feedback, suggesting that explanations enhance the effectiveness of a correction by increasing belief in the feedback. These findings imply that successful correction of common misconceptions is likely enhanced by techniques that increase people's belief in the validity of the corrective feedback. (PsycINFO Database Record

Analyzing Confabulations in Schizophrenia and Healthy Participants.

OBJECTIVES: Confabulations occur in schizophrenia and certain severe neuropsychiatric conditions, and to a lesser degree in healthy individuals. The present study used a forced confabulation paradigm to assess differences in confabulation between schizophrenia patients and healthy controls. METHODS: Schizophrenia patients (n=60) and healthy control participants (n=19) were shown a video with missing segments, asked to fill in the gaps with speculations, and tested on their memory for the story. Cognitive functions and severity of symptoms were also evaluated. RESULTS: Schizophrenia patients generated significantly more confabulations than healthy control participants and had a greater tendency to generate confabulations that were related to each other. Schizophrenic confabulations were positively associated with temporal context confusions and formal thought disorder, and negatively with delusions. CONCLUSIONS: Our findings show that the schizophrenia patients generate more confabulations than healthy controls and schizophrenic confabulations are associated with positive symptoms. (JINS, 2016, 22, 911-919).

Does reactivating a witnessed memory increase its susceptibility to impairment by subsequent misinformation?

In a recent PNAS article, Chan and LaPaglia (2013) provided arguments and evidence to support the claim that reactivating a witnessed memory (by taking a test) renders the memory labile and susceptible to impairment by subsequent misinformation. In the current article, we argue that Chan and LaPaglia's (2013) findings are open to alternative interpretations, and further test the hypothesis that reactivation increases a witnessed memory's susceptibility to impairment. To this end, the current studies used a different set of materials and a different measure of memory impairment, the Modified Recognition Test (McCloskey & Zaragoza, 1985). In Experiment 1a, we established that our reactivation manipulation was effective by showing that we could replicate the well-established retrieval enhanced suggestibility effect with our materials. However, when we assessed potential impairment of the witnessed memory with the Modified Recognition Test (Experiments 1a and 1b), we failed to find evidence that reactivating the witnessed memory prior to misinformation impaired memory for the originally witnessed event. In Experiment 2, we replicated Chan and LaPaglia's (2013) findings when we used their memory impairment measure (misinformation-free True/False Recognition Test) and showed why that test does not permit clear inferences about memory impairment. Collectively, the results showed that, although the reactivation manipulation increased susceptibility to suggestion (i.e., as evidenced by increased reporting of suggested misinformation), there was no evidence that reactivation through testing increased the original memory's susceptibility to impairment.

The continued influence of implied and explicitly stated misinformation in news reports.

The piecemeal reporting of unfolding news events can lead to the reporting of mistaken information (or misinformation) about the cause of the newsworthy event, which later needs to be corrected. Studies of the continued influence effect have shown, however, that corrections are not entirely effective in reversing the effects of initial misinformation. Instead, participants continue to rely on the discredited misinformation when asked to draw inferences and make judgments about the news story. Most prior studies have employed misinformation that explicitly states the likely cause of an outcome. However, news stories do not always provide misinformation explicitly, but instead merely imply that something or someone might be the cause of an adverse outcome. Two experiments employing both direct and indirect measures of misinformation reliance were conducted to assess whether implied misinformation is more resistant to correction than explicitly stated misinformation. The results supported this prediction. Experiment 1 showed that corrections reduced misinformation reliance in both the explicit and implied conditions, but the correction was much less effective following implied misinformation. Experiment 2 showed that implied misinformation was more resistant to correction than explicit misinformation, even when the correction was paired with an alternative explanation. Finally, Experiment 3 showed that greater resistance to correction in the implied misinformation condition did not reflect greater disbelief in the correction. Potential reasons why implied misinformation is more difficult to correct than explicitly provided misinformation are discussed. (PsycINFO Database Record

The Impact of Multifaceted Questions on Eyewitness Accuracy Following Forced Fabrication Interviews.

Lawyers will frequently use complex-question forms, such as multifaceted questions (single questions that contain both a true and a false proposition), when cross-examining witnesses, and prior research has shown that use of such questions reduces testimonial accuracy. The present study extends this research by using a forced fabrication paradigm (Chrobak & Zaragoza, 2008) to assess how multifaceted questions might affect eyewitness suggestibility after exposure to misleading post-event information. Consistent with prior studies, the use of multifaceted questions led to lower accuracy than simple questions. The novel finding was that multifaceted questions caused larger impairments in performance among fabrication participants (who had earlier been suggestively interviewed), than in control participants (who had not). We also provide preliminary evidence that the impairment caused by multifaceted questions is due to both (a) having to consider two propositions simultaneously, and (b) the shift in question focus from the fabricated event to a true event.

When forced fabrications become truth: causal explanations and false memory development.

Studies of text comprehension have amply demonstrated that when reading a story, people seek to identify the causal and motivational forces that drive the interactions of characters and link events (e.g., Zwaan, Langston, & Graesser, 1995), thereby achieving explanatory coherence. In the present study we provide the first evidence that the search for explanatory coherence also plays a role in the memory errors that result from suggestive forensic interviews. Using a forced fabrication paradigm (e.g., Chrobak & Zaragoza, 2008), we conducted 3 experiments to test the hypothesis that false memory development is a function of the explanatory role these forced fabrications served (the explanatory role hypothesis). In support of this hypothesis, participants were more likely to subsequently freely report (Experiment 1) and falsely assent to (Experiment 2) their forced fabrications when they helped to provide a causal explanation for a witnessed outcome than when they did not serve this explanatory role. Participants were also less likely to report their forced fabrications when their explanatory strength had been reduced by the presence of an alternative explanation that could explain the same outcome as their fabrication (Experiment 3). These findings extend prior research on narrative and event comprehension processes by showing that the search for explanatory coherence can continue for weeks after the witnessed event is initially perceived, such that causally relevant misinformation from subsequent interviews is, over time, incorporated into memory for the earlier witnessed event.

False Memories for Suggestions: The Impact of Conceptual Elaboration.

Relatively little attention has been paid to the potential role that reflecting on the meaning and implications of suggested events (i.e., conceptual elaboration) might play in promoting the creation of false memories. Two experiments assessed whether encouraging repeated conceptual elaboration, would, like perceptual elaboration, increase false memory for suggested events. Results showed that conceptual elaboration of suggested events more often resulted in high confidence false memories (Experiment 1) and false memories that were accompanied by the phenomenal experience of remembering them (Experiment 2) than did surface-level processing. Moreover, conceptual elaboration consistently led to higher rates of false memory than did perceptual elaboration. The false memory effects that resulted from conceptual elaboration were highly dependent on the organization of the postevent interview questions, such that conceptual elaboration only increased false memory beyond surface level processing when participants evaluated both true and suggested information in relation to the same theme or dimension.

Inventing stories: forcing witnesses to fabricate entire fictitious events leads to freely reported false memories.

Studies of the forced fabrication effect have shown that participant witnesses are prone to developing false memories for specific items or details that they have been forced to fabricate earlier (e.g., what type of hat someone wore). Building on these earlier findings, the present study assessed whether participants would develop false memories if forced to fabricate entire fictitious events that were more complex and extended in time and involved people, locations, and actions that they had never seen. Participants vehemently resisted fabricating these events, and false memory development over the short term (1-week recognition test) was limited. However, after 8 weeks, participants freely reported their forced fabrications nearly 50% of the time and did so even when they had correctly and publicly rejected them earlier on the 1-week recognition test. This is the first evidence that participant witnesses will freely incorporate into their eyewitness accounts entire fictitious events that they have earlier been forced to fabricate.

A little elaboration goes a long way: the role of generation in eyewitness suggestibility.

Although research has documented that perceptual elaboration (e.g., imagery) can increase false memory, prior research has not ascertained whether such effects are due to the act of generation or simply from exposure to perceptual details. Two experiments explored this question using the eyewitness suggestibility paradigm. Experiment 1 compared the effect of generating descriptions of suggested items with the effects of reading elaborated versions of the items or the suggested items alone. Experiment 2 compared participants who generated descriptions to participants who read the same descriptions. Generating a description increased false memory and increased accurate memory for the items' actual source, relative to comparable control conditions. Generation also increased claims of having a (false) vivid recollection of the items in the event. Overall, the results suggest that conditions that require people to describe the appearance of objects that they do not remember are even more pernicious than conditions that involve exposure to such details.