Halo effect, a fallacy in the casino

The halo effect is a fallacy that unnoticeably influences our daily life. And therefore also on our gaming behavior. First, let’s take a look at Rob and Erik. They turned eighteen and they go to Holland Casino (Amsterdam center) for the first time .

Rob and Erik walk directly to the roulette table almost immediately upon arrival . They play ten rounds, eight of which Rob successfully completes and makes a profit. Erik, on the other hand, loses all the money he took to play. When he turned in frustration on the last round, he also got a glass of water over him from an awkwardly passing woman.

Halo effect

Rob has fond memories of the casino visit and the roulette game. Erik wants to go to the casino again, but he doesn’t like roulette. Next time he looks for his success with the slots . It is a simple example of the halo effect.

Simply explained, you could consider the halo effect as the result of a first impression. Officially, it says that when someone perceives some positive things, someone assumes that other things are also positive. So it doesn’t necessarily have to be a first impression, but it often is.

Assess people

An example often given in explaining the halo effect is the assessment of a person. You may already have an idea of ​​Rob and Erik from the above. That is why the halo effect already works. But this would be the much given example, who do you judge the most favorably with the description below:

Erik – intelligent – diligent – impulsive – critical – stubborn – jealous

Rob – jealous – opinionated – critical – impulsive – diligent – intelligent

Most people turn out to be the most positive about Erik. Strange, because Rob’s properties are exactly the same. They are only reversed, putting the least positive trait in front. But it could be that you already chose Rob because he is a winner in the earlier story and you saw Erik as a ‘clumsy loser’ who has lost all his money .


The halo effect is mainly a result of laziness. We have to process so much information every day that our brains especially want to do it quickly. Contradictory assessment is difficult and time consuming, we want a coherent story quickly. So if the first assessment is positive, the rest will also be positive.

Psychologists and others discussing the halo effect usually give examples around individuals. However, this fallacy also works with all kinds of other things that we form an opinion about, such as products, companies and plans. Of course people often play a role in this. After a previously bad plan from Kees or Marianne, you don’t expect much from the plan you get from them afterwards.

Consequences of halo effect

The halo effect can have special consequences. For example, many people value the opinion of a singing celebrity about a serious subject more than that of an expert. Because the celebrity is good at one thing, he will also be good at the other.

The same happens due to the halo effect for jobs and professions. People move on to positions for which they do not have the capabilities, just because they made a good impression in their previous position.

Magnet against gambling addiction

A magnet against gambling addiction? Yes, it may sound a bit strange. And if you have a friend who has been behind the slot machine for too long, you shouldn’t go straight to the Gamma or Praxis to buy one. It is not just any magnet.

The Italian neurologist Antonello Bonci has been researching (gambling) addiction and cocaine addiction for years . He does this both in Italy and at various universities in the United States. He gradually discovered the receptors in the brain that play a role in addiction. Not only with drugs, but with every form of addiction.

Magnet against gambling addiction

Bonci started working with magnets a few years ago. That gave positive results. He and the teams he worked with intensified their research. It was then clear for a long time that the results of their research with cocaine addicts would also work for gambling addicts.

For example, because addictions have in common that they stimulate the brain’s pain and reward system. Read the previous article about dopamine and gambling addiction about this .

How it started

Bonci conducted research in Baltimore around 2010. With colleague Billy Chen, he made rats highly addicted to cocaine. The bugs were always looking for the drug. In fact, they were so addicted that they tolerated painful electric shocks to their legs in order to receive drugs.

Bonci and Chen also genetically manipulated the rats. This allowed them to control parts of the rat brain with light, for example. When they stimulated the rats’ brains in the prefrontal cortex, an area behind the forehead, the rats immediately stopped looking for cocaine. This prompted the researchers to conduct new experiments aimed at that area.

Magnetic stimulation

Bonci used magnetic stimulation of the left dorsolateral prefrontal cortex in one of the experiments . This magnetic stimulation (TMS) has already been widely used in the medical environment, for example in the treatment of depression. Promotion of the aforementioned area turned out to be promising; much later also in people with both cocaine and gambling addiction (comorbidity).

In addicts, two circuits in the frontal lobe are set incorrectly. The area that inhibits addiction is brain activity too low. And in the part of the brain that fuels the need for the addiction object, it is too high. With magnetic stimulation, Bonci regulates the activity and gets it into a better balance.

A research example

The magnet against gambling addiction and other addictions is placed in front of the forehead. The firing of magnetic signals then affects the nerve cells.

One of the first studies involved 29 cocaine addicts. They used an average of 2 grams of cocaine every other day. Bonci divided the study participants into two groups. One group was treated with the magnet, the other group was not treated. Both groups were not allowed to use cocaine afterwards. This was checked with urinalysis.

After nearly a month, 3 of the untreated participants were found to be cocaine-free. Of the group that had undergone the magnetic stimulation, 10 had stopped using cocaine.

Practice application

Shortly after Bonci’s initial results, several practitioners set to work on the findings of him and his colleagues. In Italy, for example, Luigi Gallimberti, an addiction doctor at a private clinic in Padua, replaced the rats with humans. He experimentally applied the rTMS technique to 32 cocaine addicts.

This turned out to be extremely successful, so that Gallimberti offered it more often as therapy. There was closer collaboration with Bonci. Together they opened a clinic in Milan in 2017. Gallimberti has now helped more than 350 addicts.

More research

Bonci himself continued to research. He was able to work with increasingly refined techniques, due to technological developments. The results improved and there was greater interest from other universities, disciplines and addiction environments. Which is why the magnet against gambling addiction also got attention.

Investigations are now underway in several countries. They are experiments with, for example, different strengths of magnet stimulation. But also research into forms of therapy. The latter is generally important because psychological counseling is still necessary for most treatments to prevent relapse.