Experimental evidence that illusory feelings of prediction can be caused by familiarity detection

Déjà vu is the sensation that a situation feels familiar while believing that it has never been encountered before. An interesting facet of déjà vu is that it is often associated with an illusory sense of knowing what will happen next (feelings of prediction, or FOPs). Research has shown that déjà vu accompanied by FOPs carries with it higher perceived familiarity intensity than déjà vu unaccompanied by a FOP. However, these findings have mainly been correlational, making it unclear if the sense of familiarity itself plays a causal role in FOPs. In three experiments, we examined whether experimentally increasing familiarity can causally drive FOPs. In a variant of a method previously used to study déjà vu, participants completed virtual tours of novel scenes that each had their spatial layout familiarized to a different degree (a scene with a similar layout was earlier presented three times, once, or not at all). Participants were asked if the novel scene felt familiar, if they had a sense of what would happen next, and to predict what would happen. Participants were never asked about feelings of déjà vu to eliminate the possibility that prompting the déjà vu experience could lead participants to think they should respond a certain way to the other questions. When participants could not actually recall the similar studied scene, FOPs increased with increases in experimentally created spatial layout familiarity. These results suggest that familiarity-detection itself can produce FOPs during déjà vu, and potentially outside of déjà vu as well.