Daniel Sanabria, psychologist: "The best predictor of professional success is not cognitive performance, it is that your parents have money"

Exercise can help increase your thinking ability, Scott McGinnis, a neurologist at Harvard Medical School, says in a press release from his institution.

"For healthy people, regular exercise can improve brain function throughout life, not just after training," he writes in an article published by

David Jacobs, a professor at the University of Minnesota.

The list of researchers and popularizers who take for granted the cognitive improvement of physical exercise is long and a good number of studies seemed to support this position.

However, a few days ago, Daniel Sanabria Lucena (Bordeaux, France, 46 years old) and his team published a review of studies in the journal

in which they included 109 works in which more than 11,000 people had participated in which a positive effect of exercise on cognition had been found.

After analyzing them in depth, they found that this effect did not have strong evidence to support it.

"Knowledge on this subject is not advanced enough to be able to make recommendations as forceful as those that are made," he says in an interview by video call, and recalls that his group "is not the first to have said it."

Adele Diamond, of the University of British Columbia in Vancouver, also states that "aerobic exercise, resistance training, or yoga have not been shown to improve higher cognitive functions," including the ability to plan, make decisions or working memory.

"But we don't talk about mental health, which is a different topic," Sanabria points out.

Ask.

Studies like yours show the difficulty of offering definitive prescriptions on many aspects of health.

Do you think that people can learn to live with this uncertainty and not accept clear but baseless advice?

Answer.

First of all, I think that scientific education is needed in the population, starting from school, so that people understand how science works.

It is important to know that researchers have our biases, interests and prejudices.

For some, science has become a kind of religion, a source of absolute certainties, and it doesn't really work that way.

People want to know what they have to do to take care of their well-being, including their mental one.

We want simple recipes.

But, on most occasions, giving recipes is complicated, to which is added, as we saw in the pandemic, that we are not very tolerant of uncertainty.

In my own classes, I remember discussing two conflicting theories about a phenomenon, and one person asked me: So what am I to believe?

I told them that science is not about believing, it is about generating theories and accumulating evidence that can be more or less solid and conclusive in favor of one hypothesis or another.

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Q.

So, as your students would say, what do we do with the exercise?

A.

In this specific case, from what we know, what I would say is that if exercising makes you feel good, do it.

Because there is also very solid evidence about the benefits for physical health.

Q.

How do all these studies that have led us to believe that exercise had a positive effect on cognition come about?

R.

In the last two decades there has been a growing interest in this subject, looking for benefits of physical exercise beyond physical health.

Studies have been done looking for relationships between the level of physical activity of a group of people, in some cases with thousands of participants, their level of cardiovascular fitness and cognitive performance.

These studies show correlation, but correlation does not mean causation.

That is why intervention studies have been carried out, where you randomly assign people to the experimental group, who do physical exercise, and other people to the control group, who do not do physical exercise, or who do an activity that, you assume, will not work. have an impact at the cognitive level.

The evidence obtained from this type of study is what is frequently used to affirm that physical exercise improves cognition.

We have analyzed 109 of these studies , those that focus on healthy populations, and the conclusion is that the evidence on these supposed cognitive benefits is not conclusive at all.

In fact, we think that intervention studies may not be the best tool to study the possible effects of regularly practiced exercise at the cognitive and brain level, and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

We have analyzed 109 of these studies , those that focus on healthy populations, and the conclusion is that the evidence on these supposed cognitive benefits is not conclusive at all.

In fact, we think that intervention studies may not be the best tool to study the possible effects of regularly practiced exercise at the cognitive and brain level, and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

We have analyzed 109 of these studies , those that focus on healthy populations, and the conclusion is that the evidence on these supposed cognitive benefits is not conclusive at all.

In fact, we think that intervention studies may not be the best tool to study the possible effects of regularly practiced exercise at the cognitive and brain level, and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

and the conclusion is that the evidence on these supposed cognitive benefits is not conclusive at all.

In fact, we think that intervention studies may not be the best tool to study the possible effects of regularly practiced exercise at the cognitive and brain level, and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

and the conclusion is that the evidence on these supposed cognitive benefits is not conclusive at all.

In fact, we think that intervention studies may not be the best tool to study the possible effects of regularly practiced exercise at the cognitive and brain level, and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

and that it would be better to obtain evidence from longitudinal studies.

If we obtain conclusive evidence about the existence of these effects, there would be the question of "why", but that is enough for another interview.

And then there is that, sometimes, the results are not published when the desired effect does not come out.

Q.

So, are there results that, because they are more attractive, are searched for more and come out more?

R.

A paradigmatic example is bilingualism, the advantage of being bilingual at a cognitive level.

Between 2000 and 2010, there was a boom of articles showing that people who spoke more than one language were cognitively better than monolinguals.

I have come to see examples of bilingual schools selling bilingualism as a tool to improve the cognitive ability of their students.

However, papers showing publication bias [the tendency for positive results to be published more than null results] appeared, especially in groups that were quite prolific in that field.

In addition to this, in this topic of bilingualism and cognitive performance, studies with quite large samples and null results have emerged in recent years.

In the case of physical exercise, we have carried out several works that, at first glance, could show counterintuitive results.

One is about mental fatigue in physical performance.

Today there is literature that says that if you do a demanding mental task just before doing physical exercise, you will perform worse physically than if you do something less demanding before.

In sports science it seemed something assumed.

We tried to replicate a classic study in this line and obtained null results, and then we began to question the quality of the evidence.

We started looking at the literature and the studies used very small samples of subjects.

We did a meta-analysis and, indeed, there were very small samples, which increases the probability of finding a false positive, poor-quality studies, and publication bias.

And another line of research in which we have worked is the one that looks for the effects of electrical brain stimulation by direct current, of low intensity, to improve physical and sports performance.

There was even a company that sold a device that stimulated the brain to improve physical performance.

We did an empirical study, trying to replicate previous results and, again, we found a null result.

We did a meta-analysis, and again we found studies with very small samples, publication bias, and inconclusive literature.

That being said, the results of our research that I have discussed here do not mean that these effects do not exist, since the absence of evidence of an effect is not evidence of the absence of an effect.

What they indicate is that, with the studies available so far, nothing can be concluded about these phenomena.

More and better research is needed.

Daniel Sanabria, in Granada, in March.

fermin rodriguez

Q.

Does the way people are chosen to participate in the studies affect the results?

R.

It can have a significant impact, yes.

For example, imagine a call for participation is made that says they are looking for older people for a study that wants to look at the effects of exercise on cognitive and brain performance in preventing cognitive decline.

Who is going to sign up?

It is very likely that they are people who have an interest and expectation that the exercise will have an effect on their brain.

And this group, in many studies, is compared to one of the so-called “waiting lists”, who continue their normal lives, who do nothing.

They don't buy that in medicine anywhere.

You always have to have a placebo group, because you know that the expectations about the effect of a drug can already have an effect.

Besides,

In our recent review study on the effects of exercise at the cognitive level, we have seen that in many studies, people in the experimental group, who receive physical exercise training, tend to start from a lower point in their cognitive performance than people included in the control group, which did not receive the physical exercise intervention.

Therefore, the experimental group has more room for improvement than the control group.

That this difference between the groups before starting the intervention tends to be in favor of the experimental group in many studies could be another indicator of publication bias.

they tend to start from a lower point in their cognitive performance than the people included in the control group, who did not receive the physical exercise intervention.

Therefore, the experimental group has more room for improvement than the control group.

That this difference between the groups before starting the intervention tends to be in favor of the experimental group in many studies could be another indicator of publication bias.

they tend to start from a lower point in their cognitive performance than the people included in the control group, who did not receive the physical exercise intervention.

Therefore, the experimental group has more room for improvement than the control group.

That this difference between the groups before starting the intervention tends to be in favor of the experimental group in many studies could be another indicator of publication bias.

Q.

Does the explanation of the effects of psychological outcomes place too much emphasis on the effects on the brain and not enough on the context?

R.

One of the dangers of this topic of measuring the effects of something, and it is valid for exercise, mindfulness

whatever, is that very relevant factors are usually ignored, which are context factors.

The best predictor of academic performance and subsequent professional success is not cognitive performance, it is the sociocultural context.

That your parents have money.

Some ways of interpreting the results send us a subtle message, which places responsibility on the individual.

If you're fat it's your fault, and it has nothing to do with being surrounded by junk food, if you don't exercise and you get sick it's because of your lack of will… I think that's dangerous.

Q.

Although that is true, it is not incompatible with limiting the amount of junk food accessible and telling people that part of their health is in their hands, going for a run or trying to buy less ultra-processed food.

R.

Totally agree, it is not incompatible.

And I don't want it to be the message of our work.

I recommend people exercise, of course.

But, above all, if you plan to enlist your son or daughter to practice a sport or play chess, do it to see if they like it, but not to look for an effect on their mind, because the effects, if they exist, are small and, to this day, scientific evidence is not conclusive in this regard.

And I think it's important to stress again that not all of the responsibility for physical and mental well-being should rest with the individual.

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