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Neuromarketing: Why does our brain deceive us?

Although we may believe that we are fully aware of all the decisions we make, in reality our brain decides for us without us often being able to use logical and rational thinking. It is estimated that between 85 % and 95 % of our decisions are made unconsciously.. But how is this possible?



Let's start with the dual process theory, which proposes the existence of two ways of thinking:

  • The system 1 or thought fast and intuitive. It integrates automatic processes that take place unconsciously in the background. This requires less mental activity and, therefore, less effort. It is based on past experiences, emotions, working memory... The existence of system 1 lies in the our brain's need to save energy. It would be exhausting to rationally analyze every component of every decision we make throughout the day.
  • The system 2 or thought slow and thoughtful. It involves processes that require logical and analytical reasoning. This requires conscious thought that entails more time for reflection.

Therefore, making certain decisions using system 1 saves time and energy. The speed of this thinking is based on mental shortcuts developed over time based on past experience.

These shortcuts are called heuristics. Its function is to simplify and filter the information we receive. However, this way of proceeding can lead to erroneous conclusions or, in other words, cognitive biases.

Heuristics and biases


Among the most outstanding heuristics we can find the following:

  • Heuristic of representativeness. It consists of making judgments based on the resemblance of certain situations to others. That is, judging the probability that a person or thing belong to a group or category based on the similarity between the person and the members of the group. 

For example, if we describe Peter as a shy, tidy, detail-oriented person, what do we think he might be a farmer, an airline pilot, or a librarian? Our first thought leans toward the librarian option. This is because Peter's description best fits the idea we have about librarians. However, by statistics, Peter is more likely to be a farmer.

  • Heuristic of anchoring and adjustment. It consists of making judgments based on a initial value (anchor) that is being adjusted until the final answer is generated. This answer is biased towards the initial value, since it is assumed to be relevant to the problem, being wrong in many occasions. 

For example, when asked the question "Do you think that at the summit of Everest the water boils at a temperature higher or lower than 10 degrees? Even if we have no idea, our answer will probably look for a value that fits those 10 degrees, because we consider that this is relevant information. However, it has nothing to do with it, since the correct answer is 69 degrees. If we were to ask the same question with another value as an anchor, the answer would still be adjusted to that new value.

  • Heuristic of availability. It is used to determine the probability of an event occurring or not. The more accessible it is This event (or another similar one) in our mind or easier to remember, will seem more frequent and probable. 

For example, if we ask, is it more likely to die from a shark attack or from the impact of a falling piece of an airplane? We would probably think that the shark attack is more likely, since it is easier to remember because they are more shocking and appear more frequently in the media. However, the probability of being killed by an airplane part is 30 times higher.


There are countless categories and types of biases, so let's review some of them:

  • Halo effect. It is the capacity we have to changing a person's perception or thing by extrapolating a specific quality. That is, if a person or element has visual appeal, we automatically attribute positive characteristics to it. And vice versa. For example, if we see a person with a lot of tattoos and piercings, what do we think about them? What job do we think they have? What do we think their character is like? What about their family life? With that description, we create a picture in our heads that helps us answer those questions, but it doesn't have to match reality.
  • Forer Effect. It is the phenomenon by which people feel that they are identified with descriptions or personal traits thinking that they define them, but in reality they are general and not very specific. They feel identified because they apply a subjective meaning to it and thus perceive it as something personal. This is the basis of the horoscopes.
  • Bandwagon effect or dragging. It is the tendency to make or understand sth. by the fact that other people think so or they do. It's the power of groupthink.

A clear example is the Asch's experimentwhich sought to demonstrate how individuals alter their responses or behaviors to make them fit with those of the majority. A group of people were asked a series of simple questions. These included deciding which of the lines was longer or which of the lines matched the reference line:Asch's experiment

In this group of people, all knew the purpose of the experiment except one. At the beginning, in order to disguise it, all the answers given were correct, but as the questions went by, the subjects answered wrongly (being all aware of it, except one). The result was that, based on the carry-over effect, the only real subject in the experiment ended up matching his answers to those of the majority, even though he knew they were not correct.

  • Environmental perception effect. The environment has a great influence on behavior of people. In a chaotic, deteriorated and dirty environment, people tend to be more uncivic and chaotic, even committing vandalism or criminal acts.

Broken windows theory

An interesting example is the broken windows theoryan experiment conducted by psychologist Philip Zimbardo. Two cars were abandoned without license plates and with their doors open in the Bronx (a troubled neighborhood in NY) and in Palo Alto (a wealthy and quiet area of California). Within 10 minutes of being abandoned, the Bronx car was stolen. After three days there was nothing of value left. Then they started to vandalize it. In contrast, the Palo Alto car, after a week, remained intact. The investigators broke the glass to test the effect it had. After that, the car suffered the same fate as the one abandoned in the Bronx: theft, violence and vandalism.

  • Frequency illusion. It is the phenomenon whereby, after focusing on a specific event, we believe we see it more often around us. The explanation lies in the fact that we are the ones who perceive this event in a different way, since before we probably did not pay so much attention to it and thought it was not so frequent. This happens, for example, when we buy a certain car and suddenly we see it everywhere. Has there been a massive sale of that model? No, but before you probably didn't notice that particular car. Another clear example happens when a person around you announces her pregnancy. It is likely that walking down the street you notice all the pregnant women and think that there has been a baby boom, but in reality this is not the case.
  • Reference point or status-quo. This bias explains the difference between each person's point of reference, which causes a perception or different values for the same event. For example, a person with a salary of €1,500 may feel that he or she earns a lot if all his or her circle of relatives or friends have salaries below €1,000. However, another person with a salary of €1,500, but who moves in a circle where the average salary is €2,500, may feel that he/she is underpaid. For the same amount, the perception may be different depending on the reference we take.

And so much for our incursion into the world of the heuristics and biasesWhat did you think? Would you like to know more about them? Tell us in the comments.

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