Case File 309 · Investigation Psychology

What Is Belief Perseverance?

By Murder Book Editorial TeamPublished by Gungrounds, the studio making Murder BookPublished 3 October 2026Updated 3 October 2026

Belief perseverance is the tendency to maintain a belief even after the evidence that originally supported it has been shown to be false. In a criminal investigation, this means that once an investigator forms a theory about a suspect or a sequence of events, that theory can persist even when new evidence contradicts it or when the original basis for the theory is discredited. The effect was demonstrated in a landmark 1975 experiment by Ross, Lepper and Hubbard, who showed that participants continued to hold beliefs about their own abilities even after being told that the feedback those beliefs were based on was entirely fabricated. Belief perseverance is not a sign of incompetence. It is a well-documented feature of human cognition that affects everyone, including experienced professionals.

Key takeaways

Belief perseverance causes people to hold onto initial beliefs even after the supporting evidence is discredited.
Ross, Lepper and Hubbard demonstrated the effect in 1975 using fabricated feedback that participants continued to believe after debriefing.
In investigations, the bias can keep a discredited theory alive, leading to tunnel vision and potential miscarriages of justice.
The effect is strengthened by confirmation bias and hindsight bias, which make the original belief feel well-supported and inevitable.
Generating explanations for why an alternative theory might be true is one of the most effective ways to counteract belief perseverance.

How was belief perseverance discovered?

The classic experiment was published in 1975 by Lee Ross, Mark Lepper and Michael Hubbard in the Journal of Personality and Social Psychology. Participants were given a task distinguishing real suicide notes from fictional ones. After each response, they received feedback telling them whether they had done well, poorly, or about average. The feedback was entirely fabricated and had no connection to their actual performance.

After completing the task, participants were thoroughly debriefed: they were told that the feedback was predetermined and random, that it said nothing about their real ability. Despite this clear debriefing, participants who had received positive feedback continued to rate their ability at the task higher than those who had received negative feedback. The initial false belief persisted even after its foundation was removed.

A follow-up experiment showed why. When people receive initial evidence for a belief, they spontaneously generate causal explanations to support it. Once those explanations exist, discrediting the original evidence does not automatically erase them. The explanations take on a life of their own.

Why does belief perseverance matter in investigation?

In criminal cases, investigators form working hypotheses early. A witness statement, a piece of forensic evidence or an alibi inconsistency can point toward a particular suspect. If that initial evidence is later shown to be unreliable, for example if a witness recants or forensic results are re-examined, belief perseverance can keep the original theory in place.

Findley and Scott's 2006 analysis of wrongful convictions in the Wisconsin Law Review found that tunnel vision runs through nearly every documented case. Belief perseverance is one of the psychological mechanisms that sustains tunnel vision. Once investigators have built a mental narrative around a suspect, they generate explanations and connections that feel independent of the original evidence, even when they are not.

This is not about dishonesty. Investigators who persist with a discredited theory typically believe they are following the evidence. The problem is that the mental explanations they have constructed feel like evidence, even though they were generated to support a conclusion rather than discovered independently.

How does belief perseverance interact with other biases?

Belief perseverance rarely operates in isolation. Several related biases reinforce it:

Confirmation bias leads investigators to seek and interpret new information in ways that support the existing theory. Nickerson's 1998 review documented this across hundreds of studies and called it one of the most well-established biases in psychology.
Hindsight bias makes the chosen theory feel inevitable in retrospect, which strengthens the sense that it must be correct.
Anchoring bias gives disproportionate weight to the first piece of information encountered, making it harder to update away from the initial suspect or theory.

Together, these biases create what Findley and Scott described as the multiple dimensions of tunnel vision: not a single error, but a cluster of cognitive tendencies that push in the same direction.

What does the research say about overcoming belief perseverance?

The most effective technique identified in the research literature is considering the opposite. Lord, Lepper and Preston published a study in 1984 in the Journal of Personality and Social Psychology showing that when participants were explicitly asked to consider whether the opposite conclusion might be true, they showed significantly less bias than those who were simply told to be fair and objective.

This has practical implications for investigation. Rather than asking investigators to "keep an open mind," which is vague and difficult to act on, a structured process of generating alternative explanations for the evidence can directly counteract belief perseverance. If a witness places a suspect at the scene, the investigator asks: what are three reasons this witness might be wrong? If forensic evidence appears to match, the investigator asks: what other explanations could account for this match?

Awareness training also helps. Research on forensic decision-making has found that simply knowing about belief perseverance and related biases can reduce their effects, particularly among less experienced practitioners. However, awareness alone is less effective than structured debiasing techniques.

Can a discredited theory still lead to a wrongful conviction?

Yes. The wrongful conviction literature documents cases where initial evidence was later undermined, but the investigation continued along the same path. Kassin, Bogart and Kerner's 2012 study of 241 DNA exoneration cases found that multiple errors appeared in three out of four cases involving false confessions, and that confessions often came first, followed by other evidence that appeared to corroborate them. Belief perseverance helps explain how this happens: once a confession establishes a narrative, the mental framework it creates persists even if the confession itself is questioned.

The interaction works the other way too. If forensic evidence is gathered under the influence of a particular theory, and the theory is later discredited, reviewers who know about the theory may still see the evidence through that lens. Can knowing a suspect's confession bias other evidence? explores this dynamic in detail.

How does Murder Book relate to belief perseverance?

Murder Book: The Art of Interrogation is an upcoming narrative interrogation game from Gungrounds, an independent studio in Zagreb, Croatia. Its development screenshots show a branching case map with achievement endings and a completion percentage, meaning players can reach conclusions that turn out to be wrong. The game shows a "not guilty" result among its case outcomes, so a player who becomes convinced of a suspect's guilt may discover they were mistaken.

Development materials also show an evidence board where statements such as "I NEVER met her!" and "I had no idea" are linked to contradictory details. A player who fixes on one interpretation of those links early may find later evidence that undermines it. The structure invites players to notice when they are holding onto a theory that the evidence no longer supports, mirroring the real challenge of belief perseverance. Murder Book is in development for PC (Steam) and mobile, with release currently planned for the end of Q2 2027.