Summary: Why do people with compulsive traits—seen in OCD, addiction, and eating disorders—rely so heavily on repetitive habits? According to a new study, it’s not because they can’t plan for the future, but because they are paralyzed by uncertainty. Using an online video game played by 2,000 participants, researchers found that more compulsive individuals were significantly less certain about how their actions would play out over the long term.
This “planning paralysis” makes habitual, “model-free” choices (like reaching for a frozen pizza) feel safer than “model-based” planning (like preparing a healthy salad). By identifying this mechanistic link between uncertainty and habit, the study offers a more precise explanation for the repetitive behaviors that define compulsivity.
Key Facts
- The “Uncertainty” Mechanism: Compulsive traits are linked to a specific decision-making strategy where habits are favored because the individual feels less certain about the consequences of long-term plans.
- Model-Free vs. Model-Based: “Model-free” decisions are habitual and require no planning, while “model-based” decisions involve mentally simulating future outcomes. Compulsivity pushes people toward the former.
- Gamified Neuroscience: Researchers used a specialized “two-step” video game (shooting aliens with colored cannons) to measure how participants weigh future consequences against immediate uncertainty.
- Spectrum of Behavior: The study found that these compulsive traits exist on a spectrum across the entire population, not just in those with clinical diagnoses like OCD.
- New Clinical Insight: This suggests that treating compulsivity might require focusing on reducing uncertainty about future outcomes rather than just trying to break habits.
Source: King’s College London
Compulsive traits are tendencies to repeat patterned behaviours. They are often seen in psychiatric conditions such as obsessive-compulsive disorder (OCD), addiction and eating disorders.
However, these behaviours exist on a spectrum and are present to an extent across the population, even in people without mental health conditions.
Neuroscientists at King’s used an online video game played by 2000 people to examine the relationship between compulsive traits and different types of decision making.
The new study linked compulsive traits to a type of decision-making strategy, in which people repeat habitual behaviours rather than relying on long-term plans. Crucially, people who were more compulsive were also more uncertain about the outcomes of long-term plans, making them more likely to rely on habits.
Researchers compared the choices in the video game from participants to two different mathematical models: one based on a planning-heavy strategy and the other based on a more habitual strategy. The models also could track how certain participants were about the future consequences in the planning-heavy strategy.
Using these models, the data showed that people who scored higher for compulsive traits were both more prone to the habitual strategy and had greater uncertainty about consequences in the planning strategy.
“We found that people with more compulsive traits may rely on habits not because they can’t plan, but because they feel less certain about how their actions will play out. This gives us a more precise mechanistic explanation for patterns that have been observed for years.” – Sirichat Sookud, first author on the study.
To plan or not to plan?
People regularly make the type of decision where they can choose between a habitual or a planning-based strategy.
“After a long day of work, you immediately head to the freezer and take out a frozen pizza, almost as if without thinking. If your goal was to lower your cholesterol, you might have chosen to make a salad instead, because in the long-term you want to improve your health. Your more frequent choice, the frozen pizza, is a simpler choice that doesn’t benefit your general health goals,” explains Dr Toby Wise, Senior Research FellowNeuroscience, King’s College London.
This kind of goal-directed decision making (accounting for outcomes far off in the future) is only possible if you appreciate that eating healthily will reduce your cholesterol, ultimately improving your health. In decision making theory, this is referred to as possessing an “internal model” of how your actions lead to more distant consequences.
“If you want to eat healthier, you need to weigh up your options and mentally simulate the impact each choice will have on your long-term health. This type of decision making is often called ‘model-based’. The pizza is more of a habitual choice and doesn’t require any sort of forward planning. This type of decision is often called ‘model-free’,” says Dr Wise.
Previous studies have linked differences in goal-directed decision-making to multiple psychiatric conditions such as obsessive-compulsive disorder (OCD) and addiction. Symptoms in these disorders may arise from people choosing habitual (model-free) choices instead of goal-directed (model-based) choices. For example, someone may repeatedly check whether a door has been locked because it made them feel less distressed last time they did it, leading it to become a habitually repeated action.
The new study highlights further the role of uncertainty in these choices.
“If you are uncertain about what the future may hold, it is more likely you will reach for the choice you have made in the past,” comments Dr Wise. “Our data show that people who are more compulsive are feeling more uncertain about the future, which may explain why they shy away from model-based planning strategies in favour of habitual behaviours.”
Using video games to study behaviour
The study used a video game to understand how people make different types of choices. While being visually appealing and deployable online (enabling easy recruitment of 2000 participants), this video game contained mathematical principles that could untangle different decision-making strategies.
“Using online video games like this one makes it possible measure psychological processes remotely in huge numbers of people, providing incredible datasets and opening participation in research to a wider audience,” explains Dr Wise.
Based on a popular psychological paradigm, called the two-step task, the game can untangle if players are making choices with the future in mind. The game used in this study added another component to the task: uncertainty.
In the game, players had to shoot aliens using a cannon that could fire pink or purple balls. Balls were stored in two containers that they had to choose between, each with a mix of pink or purple balls.
Success in the game depended on two things: realising that the numbers of pink and purple balls in the two containers were related to each other (building an internal model), and learning that some balls might explode before hitting the target (uncertainty).
To hit the most aliens, players needed to combine their knowledge about the colours of the balls in each container and the chances of each colour of ball exploding mid-air.
“While this is quite a complicated process, we actually do this kind of future-oriented planning every day, and so it’s something that is quite straightforward to measure in a game,” says Dr Wise.
Funding: This research was supported by a Wellcome Trust Career Development Award.
Key Questions Answered:
A: Not exactly. This research shows it’s more about a lack of trust in the future. If you feel like your long-term plans are “blurry” or uncertain, your brain defaults to what worked in the past. Habits aren’t just routines—they are a survival strategy for a brain that isn’t sure what’s coming next.
A: Imagine driving in thick fog. You wouldn’t try to navigate a complex route you’ve never taken (planning); you’d stay in your lane and follow the taillights in front of you (habit). For someone with high compulsive traits, the “future” feels like that thick fog, making the simplest, most repetitive action feel the most secure.
A: The study suggests that the key might be in building a better “internal model” of the future. By reducing the uncertainty surrounding our goals—making the path to a reward clearer and more predictable—we might be able to nudge the brain away from habits and back toward healthy planning.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this OCD and neuroscience research news
Author: Patrick O’Brien
Source: King’s College London
Contact: Patrick O’Brien – King’s College London
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Impaired Goal-Directed Planning in Transdiagnostic Compulsivity Is Explained by Uncertainty About Learned Task Structure” by Sirichat Sookud, Ingrid Martin, Claire M. Gillan, and Toby Wise. Biological Psychiatry: Cognitive Neuroscience, and Neuroimaging
DOI:10.1016/j.bpsc.2025.10.005
Abstract
Impaired Goal-Directed Planning in Transdiagnostic Compulsivity Is Explained by Uncertainty About Learned Task Structure
Background
Diminished use of goal-directed (model-based) decision making is a hallmark of transdiagnostic compulsivity, promoting an overreliance on inflexible and habitual behaviors. However, the origin of this impairment remains unclear. Here, we tested the hypothesis that these impairments arise due to uncertainty within the internal world model that subserves goal-directed decision making.
Methods
We adapted a validated gamified decision-making task to characterize how individuals build an internal model of an environment, pairing these data with computational modeling to uncover the exact mechanisms underpinning behavior and quantify individual differences.
Two samples of participants (a discovery sample and a preregistered replication sample, n = 551 and 1322, respectively) performed the task, and we also acquired longitudinal data over 2-week and 3-month periods to assess task reliability and stability of behavior over time.
Results
In the discovery and replication samples, we found that individuals higher in compulsivity and intrusive thought learned more slowly and formed a less certain representation of the task’s structure. This uncertainty mediated the link between compulsive symptoms and use of goal-directed behavior. Behavior in the task was relatively stable over a 3-month (n = 385) and 1-year (n = 326) period and did not predict changes in symptoms.
Conclusions
Our results suggest that reliance on habitual behaviors seen in individuals with high levels of compulsive symptoms result from a tendency to form less certain internal models of the external world. Given the stability of this behavior and its links to symptoms, this may represent a trait-level vulnerability for this symptom dimension.
