This One Simple Thing Can Mitigate Your Confirmation Bias And Save Your Startup

Adi Shmorak
3 min readMay 29, 2024


In the fast-paced world of startups, founders often rely on their intuition to make critical decisions. While intuition can be valuable, it also opens the door to cognitive biases, particularly confirmation bias. This bias can cloud judgment, leading to poor decision-making. However, a simple yet powerful technique to mitigate this bias is as simple as writing down your assumptions. First, let’s understand why cognitive biases occur and why keeping ideas in our heads makes us more vulnerable to biases. Later, we’ll see why this simple practice can help overcome confirmation bias.

Why Cognitive Biases Happen: Understanding Confirmation Bias

Our brains are wired to seek consistency and avoid cognitive dissonance. Cognitive biases are systematic patterns of deviation from rationality in judgment, where your brain takes shortcuts that can lead to errors. It’s an energy-efficient mode in which we rely on patterns instead of rational judgment (which consumes more energy). One of the most pervasive is confirmation bias, where individuals favour information that confirms their pre-existing beliefs or hypotheses. For startup founders who need to validate their innovative ideas, confirmation bias is detrimental.

The Brain at Work: Keeping Ideas in Your Head

When we keep our assumptions in our heads, the brain tends to rely on automatic, intuitive processes. This involves regions such as:

  • Prefrontal Cortex (PFC): Although the PFC is involved in decision-making and critical thinking when operating on autopilot, it doesn’t engage as deeply in evaluating information.
  • Hippocampus: Responsible for forming memories, the hippocampus helps us recall supportive information more readily, reinforcing our biases.
  • Amygdala: This region involves emotional processing and can influence our intuition, often swaying our judgments based on emotional rather than rational grounds.

These processes lead to a cycle where we constantly seek out and remember information that aligns with our beliefs, reinforcing our confirmation bias.

In startups, this means our untested assumptions about the market, the product and the business can be perceived as true, without any real validation because of the confirmation bias

The Power of Writing: Activating Critical Brain Regions

Writing down your assumptions shifts the brain into a more deliberate and analytical mode, engaging different regions:

  • Prefrontal Cortex (PFC): Writing activates the PFC more intensively, enhancing your ability to analyze and evaluate assumptions critically.
  • Hippocampus: Writing creates a tangible record that aids memory consolidation, making it easier to review and question later.
  • Visual Cortex: Engaging this region by visualizing written words helps create a more concrete representation of your thoughts, which can be scrutinized more effectively.
  • Temporal Lobes: These areas help in processing language and semantics, improving the clarity and articulation of your thoughts.

Mitigating Confirmation Bias Through Writing

When you write down your assumptions, you engage these brain regions in ways that promote critical thinking and reduce bias. It’s like taking your thoughts in a different path, circumventing areas in your brain that are more susceptible to confirmation bias. This practice creates a physical record that can be revisited and questioned, encouraging a more objective evaluation. Here’s how you can implement this in your startup:

  1. Document Assumptions: Write down all key assumptions. Use a notebook or a digital tool, but ensure they are recorded clearly. I suggest using a framework like this to ensure bias mitigation and proper Product/Market Fit work.
  2. Review Regularly: Periodically review these written assumptions and update them based on new data. Look for inconsistencies and test their validity with lean experiments.
  3. Encourage Peer Review: Share your written assumptions with colleagues or mentors. External perspectives help identify biases you have missed.


In the dynamic environment of startups, overcoming cognitive biases like confirmation bias is crucial for sound decision-making. Writing down your assumptions is a simple yet effective strategy to engage critical brain regions, promoting objective analysis and better outcomes. By incorporating this practice, startup founders can enhance their decision-making processes and steer their ventures towards success.



Adi Shmorak

A Product Manager, Biz Dev Director and Mentor, working with early stage startups, helping them to focus and scale.