Case File 312 · Investigation Psychology

What Is Actively Open-Minded Thinking in Investigation?

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

Actively open-minded thinking (AOT) is a thinking disposition defined by the willingness to consider evidence that contradicts your current beliefs, to seek out alternative explanations, and to revise your conclusions when new information warrants it. Psychologist Jonathan Baron introduced the concept in the 1980s and 1990s as a foundation for rational thought. In investigation, AOT matters because the default human tendency is to look for evidence that supports an existing theory rather than evidence that challenges it. Investigators who practise actively open-minded thinking are more likely to notice when their working hypothesis does not fit the facts, and less likely to build a case around a premature conclusion.

Key takeaways

Actively open-minded thinking means deliberately seeking evidence and viewpoints that challenge what you currently believe.
Baron defined AOT as encompassing reflectiveness, tolerance for ambiguity, willingness to postpone closure, and openness to disconfirming information.
Stanovich and West developed the first widely used AOT scale in 1997, and research links higher AOT scores to better performance on reasoning tasks.
In criminal investigation, the opposite of AOT, a closed or confirmation-seeking mindset, has been linked to tunnel vision and wrongful convictions.
AOT is a habit that can be cultivated, not a fixed personality trait.

Where does the concept come from?

Jonathan Baron first named and discussed actively open-minded thinking across several publications in the 1980s and 1990s. His 1993 essay "Why Teach Thinking?", published in Applied Psychology: An International Review, argued that AOT is the foundation of rational and critical thinking. Baron described it as conscious, purposeful searching for a diverse range of opinions and facts, despite personal preferences, in order to analyse a question in an unbiased way.

Keith Stanovich and Richard West then developed the first widely used measurement scale for AOT in a 1997 study published in the Journal of Educational Psychology. Their scale treated AOT as a thinking disposition with several components: the cultivation of reflectiveness rather than impulsivity, the desire to act for good reasons, tolerance for ambiguity combined with a willingness to postpone closure, and the seeking and processing of information that disconfirms one's beliefs.

More recent work by Stanovich confirms that AOT scales are strong predictors of performance on reasoning tasks and of the avoidance of common thinking traps, including confirmation bias and tunnel vision.

What does actively open-minded thinking look like in practice?

AOT is not about having no opinions. It is about how you hold them and how you respond to evidence. Key behaviours include:

Seeking disconfirming evidence. Rather than looking only for facts that support a hypothesis, an open-minded thinker actively searches for facts that might rule it out. In an investigation, this might mean asking what evidence would clear a suspect, not just what evidence implicates them.
Considering alternative explanations. When a piece of evidence seems to point in one direction, an open-minded thinker asks whether the same evidence could also fit a different explanation. A suspect's nervousness, for example, might reflect guilt, but it might also reflect fear, confusion or the stress of being questioned. For more on this, see why investigators should consider alternative explanations.
Postponing closure. Instead of rushing to a conclusion early and then defending it, an open-minded thinker stays willing to say "I don't know yet" until the evidence is strong enough to support a conclusion.
Revising beliefs when warranted. If new evidence contradicts an existing theory, an open-minded thinker updates the theory rather than dismissing the evidence.

Why is AOT difficult?

The reason AOT requires deliberate effort is that human reasoning tends naturally toward confirmation. Raymond Nickerson's 1998 review in the Review of General Psychology catalogued confirmation bias across more than two hundred studies and concluded it was "one of the most extensively studied and well-established" biases in the field. People tend to seek, interpret and remember information in ways that support what they already believe.

Peter Wason's classic 1960 experiment illustrated this vividly. Participants were given the number sequence 2-4-6 and asked to discover the rule behind it. Most assumed the rule was "numbers increasing by two" and tested only sequences that confirmed that guess, such as 8-10-12. The actual rule was simply "any three increasing numbers." Participants who never tested a sequence that might have disconfirmed their hypothesis, such as 1-3-9, remained confidently wrong. This tendency to test only confirming cases is what Klayman and Ha (1987) called the "positive test strategy," and while it is not always irrational, it can produce systematic errors when a hypothesis is too narrow.

How does this apply to criminal investigation?

In investigation, closed-minded thinking can have serious consequences. When investigators commit early to a suspect or a theory and then interpret all subsequent evidence through that lens, the result is what researchers call investigative tunnel vision. Keith Findley and Michael Scott's 2006 analysis in the Wisconsin Law Review described tunnel vision as "the product of a variety of cognitive distortions, such as confirmation bias, hindsight bias, and outcome bias." They documented how investigators can "focus on a suspect, select and filter the evidence that will 'build a case' for conviction, while ignoring or suppressing evidence that points away from guilt."

Ask and Granhag's 2005 study in the Journal of Investigative Psychology and Offender Profiling tested this experimentally. Criminal investigators were presented with one of two alternative hypotheses about a homicide case and then read the same evidence. Investigators with a high need for cognitive closure were less likely to identify exonerating information when it contradicted their initial hypothesis. The study showed that the difficulty of abandoning a theory is not just a matter of stubbornness; it is shaped by measurable psychological tendencies.

Can actively open-minded thinking be taught?

Research suggests that AOT can be improved with practice and structured approaches. Lilienfeld and colleagues' 2009 review in Perspectives on Psychological Science, "Giving Debiasing Away," examined whether training people to recognise and correct cognitive errors can promote better judgement. They found promising evidence for techniques such as "consider the opposite," which asks decision-makers to generate reasons why their current hypothesis might be wrong.

In forensic contexts specifically, Rassin tested a "consider the opposite" intervention and found it effective at reducing confirmation bias in investigative judgement. The approach is straightforward: before settling on a conclusion, list the strongest reasons it might be incorrect, and ask what evidence would be needed to support a competing theory.

For investigators, practical AOT strategies include:

Before committing to a theory, write down at least one alternative explanation that fits the current evidence.
Assign a team member to argue the opposite position, sometimes called a "devil's advocate" or red team role.
Ask what disconfirming evidence would look like for the current hypothesis, and actively search for it.
Revisit the evidence periodically with fresh eyes, asking whether it still supports the working theory as strongly as it seemed to at first.

How does Murder Book explore this idea?

Murder Book: The Art of Interrogation is an upcoming narrative interrogation game from Gungrounds, an independent studio in Zagreb, Croatia. Development screenshots show a technique menu that includes approaches such as Confrontation and Baiting alongside Build Trust, which is described as "fostering an environment where the suspect feels comfortable and secure enough to communicate openly." The game also features a branching case map with multiple endings, including a "not guilty" result, which means players can reach wrong conclusions if they commit too strongly to one reading of the evidence.

This design reflects the core lesson of actively open-minded thinking: certainty should be earned, not assumed. The in-game casebook lists behaviours such as Avoidance, Fabrication and Narrative Gaps, but the psychology research discussed above shows that none of these behaviours proves deception on its own. A suspect who avoids a question might be lying, but might also be frightened, confused or protecting someone else. The game asks players to weigh these possibilities rather than jump to a verdict.

Murder Book is in development for PC (Steam) and mobile, with release currently planned for the end of Q2 2027.