Double misinformation and eyewitness performance: an experimental replication

Eyewitnesses may be exposed to multiple pieces of misinformation concerning the same original detail. The two misleading details contradicting each other enable detecting a discrepancy between them, which, given that only one of them can be true, should reduce credibility of the misinformation source(s) and improve reporting. This, however, can only happen at sufficiently high levels of misinformation availability (i.e., encoding of misinformation and its subsequent accessibility): with low misinformation availability, double misinformation should instead increase the misinformation effect, providing multiple chances of yielding to misinformation. To test these predictions, we experimentally manipulated misinformation availability (high vs. low) and presented double or single misinformation. However, double versus single misinformation presentation did not affect performance or interact with misinformation availability and participants frequently reported misinformation while fully detecting discrepancies between items. Therefore, discrepancy detection alone may not be sufficient in reducing the misinformation effect, with various decision-making processes involved in reporting.