Tunnel Vision (Criminal Investigation)

Tunnel vision, as a psychological metaphor, is a collection of common heuristics and logical fallacies that lead a person to focus on cues consistent with their existing opinion while filtering out cues that are inconsistent with it. It is most widely observed and researched in criminology, given its prevalence and its dangerous potential to produce wrongful convictions, and it is related to but distinct from confirmation bias: confirmation bias involves an over-reliance on external sources that may be inaccurate yet support a person's opinion, while tunnel vision is an over-reliance on internal information that leads a person to ignore correct external information, often as a result of bias carried over from a preceding case. The common remedy is a second opinion, bringing in someone unconnected to the original investigation to review it from the beginning without the same biases and preconceptions.