Case File 308 · Investigation Psychology

What Is Hindsight Bias in Criminal Investigation?

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

Hindsight bias is the tendency to look back at an event and believe it was more predictable than it actually was. In criminal investigation, this means that once a case is solved or a suspect identified, investigators, prosecutors and jurors can fall into thinking the outcome was obvious from the start. Psychologist Baruch Fischhoff identified the effect in 1975, calling it the "knew-it-all-along" phenomenon. His experiments showed that people who learned the outcome of an event consistently overestimated how predictable that outcome had been. In investigations, hindsight bias can distort how we judge earlier decisions, making reasonable investigative steps look negligent and missed clues look glaring, even when they were ambiguous at the time.

Key takeaways

Hindsight bias makes past events feel more predictable than they were, which can distort how investigative decisions are judged after the fact.
Fischhoff's 1975 research showed that knowing an outcome inflates people's belief that they would have predicted it.
In criminal cases, hindsight bias can make investigators, jurors and reviewers unfairly critical of decisions that were reasonable given what was known at the time.
The bias interacts with tunnel vision and confirmation bias, reinforcing the sense that a chosen theory was always the right one.
Awareness-based training can reduce hindsight bias, particularly among less experienced practitioners.

How does hindsight bias work?

Fischhoff's original 1975 experiments asked participants to read about historical events with four possible outcomes. Those who were told which outcome actually occurred rated that outcome as significantly more likely than participants who were not told. Crucially, the informed participants were unaware that knowing the result had changed their judgement. They genuinely believed they would have predicted the outcome beforehand.

Later research confirmed the effect across many domains. A comprehensive review by Roese and Vohs, published in Perspectives on Psychological Science in 2012, described hindsight bias as one of the most robust findings in the judgement and decision-making literature and identified three components: the sense that the outcome was inevitable ("it had to happen"), that it was predictable ("I knew it would happen"), and that one personally foresaw it ("I said it would happen").

Why does hindsight bias matter in criminal investigation?

In investigations, hindsight bias can affect multiple stages.

Judging earlier investigative decisions. Once a case reaches a verdict, reviewers and jurors look back at the investigation. Leads that were not followed, witnesses who were not re-interviewed, or forensic tests that were not ordered can look like obvious failures in hindsight, even though the significance of those steps was unclear at the time. Findley and Scott's 2006 analysis of wrongful convictions in the Wisconsin Law Review noted that tunnel vision and related biases run through almost every documented case of wrongful conviction, and that hindsight makes it harder to see how reasonable those earlier decisions appeared in the moment.

Reinforcing tunnel vision. Once investigators settle on a theory of the case, hindsight bias can make the chosen path feel inevitable. Evidence that initially seemed ambiguous now appears to point clearly toward the suspect. This reinforces the sense that alternative explanations were never plausible, even if they were.

Evaluating negligence and misconduct. In civil and disciplinary proceedings, hindsight bias can lead reviewers to hold investigators to a standard of knowledge they could not have had at the time. A study by Harley (2007), published in Social Cognition, found that jurors were more likely to judge police conduct as negligent when they knew the outcome than when they did not, even though the conduct was identical.

Can hindsight bias affect forensic experts?

Yes. A study by Ecklund, Borowsky and Lawrence, published in the Journal of Forensic Sciences in 2021, examined hindsight bias specifically among forensic mental health practitioners. They found significant hindsight bias among novice forensic evaluators: those who knew the outcome of a case rated it as more foreseeable than those who did not. Experienced forensic experts, by contrast, showed less hindsight bias, possibly because professional training and repeated exposure to uncertain outcomes had partially inoculated them.

The study also tested a debiasing intervention, asking participants to consider alternative explanations before making their judgements. This reduced hindsight bias among the novices, suggesting that structured consideration of other possibilities can help counteract the effect.

How does hindsight bias interact with other cognitive biases?

Hindsight bias rarely operates alone. It often works alongside:

Confirmation bias, which leads people to seek and favour information that supports an existing belief. Once hindsight makes a conclusion feel inevitable, confirmation bias filters new information to support it. Nickerson's 1998 review in the Review of General Psychology called confirmation bias "perhaps the best known and most widely accepted notion of inferential error" and documented it across more than two hundred studies.
Belief perseverance, which keeps people holding a belief even after the evidence supporting it has been discredited. Hindsight bias strengthens belief perseverance by making the original belief feel obvious.
Anchoring bias, which causes early information to disproportionately influence later judgements. Hindsight amplifies anchoring by making the initial anchor seem more significant than it was.

Together, these biases can create a self-reinforcing cycle. An early suspect becomes the anchor, confirmation bias filters subsequent evidence, hindsight bias makes the identification feel inevitable, and belief perseverance resists revision even when new evidence points elsewhere.

Can hindsight bias be reduced?

Research suggests several approaches:

Consider alternatives. Asking decision-makers to generate reasons why a different outcome could have occurred reduces hindsight bias. This is sometimes called the "consider the opposite" strategy.
Document reasoning in real time. When investigators record their reasoning and the information available at each decision point, later reviewers can assess those decisions against what was actually known rather than what became known later.
Awareness training. The forensic practitioner study by Ecklund and colleagues found that simply making evaluators aware of hindsight bias reduced its effects among novices.
Structured review processes. Institutional safeguards, such as requiring case reviews to consider competing hypotheses, can help counteract the pull of hindsight.

How does Murder Book explore hindsight bias?

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 multiple achievement endings and a completion percentage, meaning players can reach different conclusions from the same evidence. That structure works against hindsight bias in an unusual way: by letting players replay a case and reach a different outcome, the game shows that the "obvious" conclusion was not the only one available.

Development materials also show a technique menu that includes options such as Confrontation and Baiting alongside Build Trust, and an evidence board linking contradictory statements. Rather than offering a single clear path, the game asks players to weigh uncertain cues, recognising that what feels obvious after the fact may not have been obvious in the moment. Murder Book is in development for PC (Steam) and mobile, with release currently planned for the end of Q2 2027.