The invisible 800-pound gorilla: expertise can increase inattentional blindness.

People can fail to notice objects and events in their visual environment when their attention is engaged elsewhere. This phenomenon is known as inattentional blindness, and its consequences can be costly for important real-world decisions. However, not noticing certain visual information could also signal expertise in a domain. In this study, we compared professional fingerprint analysts and novices on a fingerprint matching task in which we covertly placed an image of a gorilla into one of the prints. This gorilla was either small, or large, but always embedded in a way that made it largely irrelevant to the primary task. We found that analysts were more likely than the novices to miss the large gorilla. We interpret this finding not as a flaw in how these experts make decisions, but most likely an expression of their expertise; instead of processing more information they filter out irrelevant information and constrain their attention to what is important.