Can we make complex decisions unconsciously?

As we have seen previously, our mind has two ways of processing information. The first one is conscious and deliberate (system 2), the second one is unconscious and intuitive (system 1). Is it a big deal? No, as our system 1 is only in charge of irrelevant and boring automatic tasks such as breathing or walking, isn’t it?

Now, would you believe me if I told you that your system 1 solves everyday complex and highly cognitive problems out of your awareness? The situation becomes more worrying. It goes against our Cartesian convictions. Recent research though, especially in neuropsychology, have shown that our brain’s executive functions, dedicated to highly cognitive tasks, can be used unconsciously*.

*Here, we do not use the term ”unconscious” in a Freudian sense (cognitivists do not like Freud so much…), but as defined in the Global Workplace Theory.

Cogito ergo sum?

High cognitive decision-making is usually divided in three steps:

  1. Problem and goal setting
  2. Planning and deliberation
  3. Evaluation of the results of our decision.

First step: Can we set goals unconsciously?

What is the goal of our action? We are not always able to answer this question, but our neurons do! Our brain can indeed set goals, even complex ones, outside of our awareness. Let’s imagine we are talking to our friend on the phone on the street. All of a sudden, we realize we have entered a supermarket. We have no idea why. We may have consciously planned to go to the supermarket before being disturbed and forgot what we wanted to buy. Yet, we may also have unconsciously realized that we needed to buy a bottle of wine as we were inviting our friend to dinner. After a few seconds of reflection, we may figure out why we entered the supermarket. Sometimes, we don’t and we just feel stupid.

Several experiments have been carried out to investigate the neural roots of this surprising cognitive mechanism. For instance, in an experiment run by a French neuroscientist, Pessiglione, images of euro coins have been projected very rapidly to participants so that they were not aware of their perception (preconscious). Then, they were asked to solve a mathematical task. The results showed that participants who had seen the images of the euros outside of their awareness perform better than those who have not seen these images. The neural analysis of the experiment confirmed that the unconscious perception of the images of the euros activated the reward system (striatum in the ‘’reptilian’’ part of the brain) while this was not the case for participants without the primings.

goal setting

Second step: Can we deliberate unconsciously?

Now we remember what we wanted to buy, we arrive at the wine department. Hundreds of bottles are in front of us, how do we choose?

1. First scenario: we think through analytically!

hook-142656_640 We try to remember what is planned for dinner and the favourite wine of our friend. But we also want a wine we like and that is not too expensive. We would like to buy a wine we know particularly well to be able to talk about it with our friend. We would also prefer an eco-friendly wine, if possible, to reduce carbon emissions. At the end, we finish with about seven different criteria to choose our bottle of wine. We can try to use our analytical system 2 by considering each criteria one by one. Unfortunately most of us cannot cope with more than five criteria at once, especially if they do not have the same importance. So the only thing we can do if we want to be rigorous is to write all our weighted criteria on a paper and make a few calculations.

2). Second scenario: we don’t have time and trust our intuition

bottle-50573_640We rarely follow the first scenario. Most of the time, we have a 2 second-long look at the bottles of wine and pick the one we “feel” is the best. In this second scenario, our system 1 has gathered a tremendous quantity of data from our environment and memory to rapidly find a solution, often approximate but rarely completely bad. All of these complex processes has of course been made unconsciously using our system 1. In other words, our neurons have rapidly solved a complex problem outside of our awareness…

What is the more effective scenario?

Recent experiments have shown that for simple decisions (where, for instance, we would have only three criteria to choose between two wines), the analytical System 2 is more effective. Yet, for complex decisions, such as choosing a bottle of wine among hundreds with seven criteria, trusting our intuitive System 1 can be a better idea. Why? Because our brain is not able to consciously manage a huge quantity of data. If we try to use our System 2 in such a complex situation, we will not finish our reasoning and finally focus on one arbitrary criteria rather than seven. The reasoning will thus be incomplete and the result will not be satisfying. An Excel file or a list paper could help us find the best wine without using our intuition by meticulously weighting each choice criteria. Although this kind of solution is often very time-consuming and boring, so we rarely use it!

In an experiment run by Dijksterhuis, two groups had to choose their favorite car in a list of four, each one described by 12 attributes. The first group was asked to read the description of the cars before doing a 4-minute long task to finally spontaneously choose their favourite car. On the contrary, participants of group 2 had 4 minutes to view and review the criteria to make up their mind. At the end, Group 1 made better decisions than Group 2. The spontaneous answer of Group 1 triggered by system 1 was better than the thoughtful answer of Group 2 , which was triggered by system 2. Further studies have shown that in both cases, groups use their prefrontal cortex which is correlated with high cognitive decision-making.


Third step: Can we evaluate our results unconsciously?

Now, it is too late! The bottle of wine is bought! The only thing we can do is to conclude whether or not it was a good choice. Again, do not worry, we can do that unconsciously!

The ‘’Go-no Go’’ test consists of pressing a key if we see a black annulus on the screen except when we see a grey circle prior to it. In the experiment described below, participants took a “Go-no GO’’ test with, sometimes, the preconscious projection of a grey circle (very fast projection so that we are not aware of this picture though our brain keeps it in memory for a brief period). Results show that when participants press the key after unconsciously seeing the grey circle, they automatically spend more time to answer the following trial as if they were unconsciously upset by the error they have just made. In both the conscious and unconscious mistakes, the Ventromedial Prefrontal Cortex (VPMC) is activated. The VPMC is a part of the Prefrontal Cortex and manages the emotional part of decision-making. In other words, we get upset to have unconsciously made a mistake!

unconsious error detection

Conclusion: our intuition can sometimes provide better solutions than our analytical mind for complex problems


Unconscious errors enhance prefrontal-occipital oscillatory synchrony
Michael X Cohen1,2* †, Simon van Gaal1,3†, K. Richard Ridderinkhof1 and Victor A. F. Lamme3 Pessiglione, M., Schmidt, L.,
Draganski, B., Kalisch, R., Lau, H., Dolan, R. J., et al. (2007).
On Making the Right Choice: The Deliberation-Without-Attention Effect, Dijksterhuis,Bos,Nordgen,Baaren
Activation of the Cognitive Control System in the Human Prefrontal Cortex, HakwanC. Lau1,2 and Richard E. Passingham
How the brain translates money into force. A neuroimaging study of subliminal motivation. Science, 316, 904–906