Learning misinformation from fictional sources: understanding the contributions of transportation and item-specific processing.

People often pick up incorrect information about the world from movies, novels and other fictional sources. The question asked here is whether such sources are a particularly potent source of misinformation. On the one hand, story-reading involves transportation into a fictional world, with a possible reduction in access to one's prior knowledge (likely reducing the chances that the reader will notice errors). On the other hand, stories encourage relational processing as readers create mental models, decreasing the likelihood that they will encode and remember more peripheral details like erroneous facts. To test these ideas, we examined suggestibility after readers were exposed to misleading references embedded in stories and lists that were matched on a number of dimensions. In two experiments, suggestibility was greater following exposure to misinformation in a list of sentences rather than a coherent story, even though the story was rated as more engaging than the list. Furthermore, processing the story with an item-specific processing task (inserting missing letters) increased later suggestibility, whereas this task had no impact on suggestibility when misinformation was presented within a list. The type of processing used when reading a text affects suggestibility more than engagement with the text.

Creating illusions of knowledge: learning errors that contradict prior knowledge.

Most people know that the Pacific is the largest ocean on Earth and that Edison invented the light bulb. Our question is whether this knowledge is stable, or if people will incorporate errors into their knowledge bases, even if they have the correct knowledge stored in memory. To test this, we asked participants general-knowledge questions 2 weeks before they read stories that contained errors (e.g., "Franklin invented the light bulb"). On a later general-knowledge test, participants reproduced story errors despite previously answering the questions correctly. This misinformation effect was found even for questions that were answered correctly on the initial test with the highest level of confidence. Furthermore, prior knowledge offered no protection against errors entering the knowledge base; the misinformation effect was equivalent for previously known and unknown facts. Errors can enter the knowledge base even when learners have the knowledge necessary to catch the errors.

Ironic effects of drawing attention to story errors.

Readers learn errors embedded in fictional stories and use them to answer later general knowledge questions (Marsh, Meade, & Roediger, 2003). Suggestibility is robust and occurs even when story errors contradict well-known facts. The current study evaluated whether suggestibility is linked to participants' inability to judge story content as correct versus incorrect. Specifically, participants read stories containing correct and misleading information about the world; some information was familiar (making error discovery possible), while some was more obscure. To improve participants' monitoring ability, we highlighted (in red font) a subset of story phrases requiring evaluation; readers no longer needed to find factual information. Rather, they simply needed to evaluate its correctness. Readers were more likely to answer questions with story errors if they were highlighted in red font, even if they contradicted well-known facts. Although highlighting to-be-evaluated information freed cognitive resources for monitoring, an ironic effect occurred: Drawing attention to specific errors increased rather than decreased later suggestibility. Failure to monitor for errors, not failure to identify the information requiring evaluation, leads to suggestibility.

Slowing presentation speed increases illusions of knowledge.

Prior research on false memories has shown that suggestibility is often reduced when the presentation rate is slowed enough to allow monitoring. We examined whether slowing presentation speed would reduce factual errors learned from fictional stories. Would subjects use the extra time to detect the errors in the stories, reducing reproduction of these errors on a later test? Surprisingly, slowing presentation speed increased the production of story errors on a later general knowledge test. Instructing the reader to mark whether each sentence contained an error, however, did decrease suggestibility. Readers appear to passively accept information presented in stories and need a constant reminder to monitor for errors. These results highlight differences between typical episodic false memories and illusions of knowledge (such as learning from fiction). Manipulations that reduce suggestibility for episodic false memories do not always reduce suggestibility for illusions of knowledge.

Learning errors from fiction: difficulties in reducing reliance on fictional stories.

Readers rely on fiction as a source of information, even when fiction contradicts relatively well-known facts about the world (Marsh, Meade, and Roediger, 2003). Of interest was whether readers could monitor fiction for errors, in order to reduce suggestibility. In Experiment 1, warnings about errors in fiction did not reduce students' reliance on stories. In Experiment 2, all subjects were warned before reading stories written at 6th- or 12th-grade reading levels. Even though 6th-grade stories freed resources for monitoring, suggestibility was not reduced. In Experiment 3, suggestibility was reduced but not eliminated when subjects pressed a key each time they detected an error during story reading. Readers do not appear to spontaneously monitor fiction for its veracity, but can do so if reminded on a trial-by-trial basis.