Believing that Humans Swallow Spiders in Their Sleep: False Beliefs as Side Effects of the Processes that Support Accurate Knowledge

Abstract Humans can store, maintain, and retrieve an impressive amount of information—but the processes that support accurate knowledge can also lead to errors, such as the false belief that humans swallow eight spiders in their sleep each year. In this chapter, we review characteristics of the knowledge base and explore how five adaptive properties that support accurate knowledge can also lead to the learning, storage, and retrieval of falsehoods. First, people exhibit a bias to believe information is true since, most of the time, incoming information is indeed true. Second, we utilize a fluency-based heuristic for judging truth since—again, most of the time—easy processing reliably signals that something is true. Third, the knowledge base is productive: people use existing knowledge to make new inferences, which are typically accurate but occasionally are inappropriate and result in errors. Fourth, existing knowledge supports new learning, so our ingrained misconceptions can foster new errors and interfere with learning the truth. Fifth, because it would be too taxing to carefully compare all incoming information to stored knowledge, we do not require a perfect match and often accept information as “good enough.” As a result, errors that are similar to the truth often slip by undetected, and sometimes are later reproduced. Finally, we discuss methods for correcting errors and potential barriers to the correction of misconceptions. In particular, it is essential to refute the error as well as provide a simple alternative to replace it. Overall, the processes that support accurate knowledge and false beliefs are the same, and can lead to competing representations in memory.