Cognitive Bias: Thinking Fast and Slow…

Ratio Bias

Let’s imagine you are dining in a very romantic restaurant.

Of course, all our attention is focused on the words and behaviors of your beloved one.

She or he is the only person who matters in this dining room. Yet, you suddenly hear the name of your firm from the conversation of the guy at the table behind you. This guy is not speaking louder than before, though.

After this disruption, you may be able to remember some of the details that this guy mentioned about your company while you were totally absorbed by your conversation with your partner.

Dining table - Free furniture and household icons

How is this possible?

Our brain has two different systems for thinking and solving problems:

System 2: conscious, deliberate and effortful. We use this system when solving analytically complex problems such as the multiplying 47*89. We are aware of the reasoning that we use to solve the problem and are thus able to explain it.

System 1: unconscious, intuitive and effortless. We use this system when performing automatic tasks such as driving or solving 2+2. However, this does not mean that the tasks managed by our System 1 are necessarily simple.

When valuing the project of a start-up, the business angel will especially rely on his/her intuitive system 1 though the task can be extremely complex.

During the dinner, we unconsciously used our system 1 when memorizing the conversation of a person behind us. But as information was not deemed to be relevant, our conscious System 2 was not activated. Our brain is not immediately aware of this conversation. But if a very important piece of information appears (the name of your company), the System 2 will be alerted and start to analyze the situation. We become aware of this discussion behind us.

This distinction between System 1 and 2 has some neural correlates, though this is still a new and sometimes controversial field of research.

According to the global workspace theory, our neurons have three ways of sorting the tremendous quantity of perceived information in its environment:

1. Subliminal treatment: perceived information is not memorized.

2. Supraliminal and unattended treatment: perceived information, like the conversation at the table behind us, is treated but we are not aware of this information. This treatment can more or less be linked to our System 1.

3. Supraliminal and attended treatment: perceived information is treated and we become aware of this information. This treatment can more or less be linked to our System 2.

How does information jump from one level of consciousness to the other? It depends on how relevant our neurons judge the perceived information.


Baars, B. J. (2005). Global workspace theory of consciousness: toward a cognitive neuroscience of human experience. Progress in brain research, 150, 45-53.

Thinking fast and slow, D. Kahneman

Dehaene, S., & Naccache, L. (2001). Towards a cognitive neuroscience of consciousness: basic evidence and a workspace framework. Cognition, 79(1), 1-37.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.