- Indecision is common, but in some people it becomes persistent and disabling, particularly in conditions such as obsessive-compulsive disorder and severe anxiety.
- A large study suggested that a specific information-processing bias can drive this pattern by weakening how strongly people update their beliefs when new evidence appears.
- When the brain fails to give fresh information its proper weight, the result is predictable: people keep searching for more evidence and still do not feel ready to choose.
Decision-making usually involves two linked processes: gathering evidence and integrating it into a judgement.
Many laboratory tasks capture this by letting participants reveal pieces of information one by one before committing to a choice.
In the study, thousands of participants completed an online task where they had to decide which of two options was more common in a grid.
They could tap to reveal as much information as they liked, then commit to a binary decision and rate their confidence. Correct answers gained points and incorrect answers lost points, creating a simple incentive to balance thoroughness with decisiveness.
The researchers analysed not just how much information people gathered, but how they integrated it over time.
A key concept was “evidence strength”, essentially the running difference in support for one option versus the other. More importantly, they examined the evidence strength update, meaning how much the running evidence changed with each new sample.
In everyday terms, this captures whether a new piece of information meaningfully shifts your belief, or whether it barely moves the needle.
The central finding was that people who reported higher indecisiveness showed reduced weighting of these updates.
When new evidence came in, their belief did not adjust as strongly as it should. This creates a trap.
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If each new sample feels only weakly informative, then no amount of sampling ever feels like enough, so the person keeps searching.
The behaviour looks like “I just need one more piece of information”, but the underlying problem is that the brain is not integrating information efficiently. The task becomes a treadmill.
The team then tested whether the same pattern appeared in a laboratory sample that included people diagnosed with obsessive-compulsive disorder, people with generalised anxiety disorder and people without a diagnosed condition.
The reduced update weighting replicated across this broader obsessive-compulsive spectrum. That matters because it suggests the mechanism is not limited to one diagnosis and may represent a transdiagnostic process that contributes to indecision across different clinical presentations.
The study also examined neural signatures using magnetoencephalography, a technique that measures fast brain activity with high temporal resolution.
They identified a neural signal linked to evidence updates that peaked late, close to a second after the update occurred, and was centred in medial frontal brain regions involved in monitoring, control and evaluation.
In highly indecisive participants across diagnoses, this neural update signal was attenuated. Importantly, other decision-relevant processes appeared relatively intact, suggesting the problem was not global cognitive impairment but a specific weakness in how incoming information is weighted and used.
This has practical implications because it suggests a targetable mechanism rather than a vague personality trait.
If indecision is partly driven by under-weighting updates, interventions could focus on strengthening how people respond to new information.
That could take the form of cognitive training that makes the impact of evidence updates more explicit, therapeutic techniques that encourage earlier commitment once a threshold is reached, or strategies that reduce repeated checking and re-sampling when the marginal value of more information is low.
It also reframes indecision in obsessive-compulsive presentations. Compulsions are often described as rituals aimed at reducing uncertainty, but if the brain is not properly updating beliefs when evidence changes, uncertainty persists even after repeated checking.
The person does not stop because the underlying signal that should say “this is enough” is weak. That explanation is not an excuse, but it is a useful model for designing better support.
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There are still limitations.
Laboratory tasks simplify real life and a points-based game cannot capture the emotional weight of decisions about relationships, health or finances. Self-reported indecisiveness also overlaps with traits such as perfectionism and anxiety.
Even so, the combination of large-scale behavioural data, replication in a clinical sample and a linked neural signature strengthens the case that the effect is real and meaningful.
The most valuable outcome of this work is clarity.
Chronic indecision is not just “overthinking”. It may reflect a measurable bias in how information is integrated, where new evidence fails to carry its proper influence.
If that bias can be modified, then indecision becomes a problem with a mechanism and a potential solution rather than a life sentence.
