All you want to do is sit on your couch and eat chips? Don’t blame yourself; the fault lies in ancestral genes that push us to minimize our efforts. And the good news? Science has found a way to counteract it: activate your cerebral cortex some more. But how to do that? And are we saying that being lazy is genetic?

Can Laziness Be Explained?

It was just another Saturday morning in my life as a father of a young boy.

I was about to leave my house to go to the park with my son. But, as soon as I crossed the house door, he used his usual tactics to get me to carry him to the park, even though it was about 150 feet from our home.

He started by bribing me emotionally on the pretext of a sudden urge to cuddle, then pretended to be tired, only to finally play his last trump card: the injury.

After letting him roll on the ground for a good five minutes, I finally surrendered and carried him to the park.

When we got to our destination, this poor, tired, and wounded little child started running, jumping, and climbing for over an hour.

While watching him, I wondered why refuse to take a few steps when you have the energy to spend more than an hour without even getting rest?

The explanation seemed pretty obvious to me. In the park, movements have a purpose in themselves, they are associated with pleasure; the pleasure of playing, experimenting, learning, or bonding with other children. On the other hand, walking to the park is not in itself interesting and, in this case, is optional since my arms were free and ready for use.

Under such conditions, why would he spend his energy? Might as well avoid unnecessary effort and save strength for later.

And there, sitting on a bench, I was wondering if this tendency to minimize effort would not be imprinted in our brain.

What Causes Laziness?

The tendency towards energy minimization is obviously not limited to our dear little ones.

For example, as adults, we prefer to use elevators or escalators rather than stairs. More specifically, in a study that examined more than 45,000 situations of choice between stairs and escalators, escalators won the fight hands down: 85% of people chose them.

We also use daily objects that allow us to reduce our physical efforts, such as automated garage doors, electric bicycles, and cars even if the next stop is just three blocks away.

For the most high-tech, perhaps you have even installed a voice assistant in your home that allows you to manage everything quietly while sitting and doing the whole thing from the comfort of your couch.

We also all tend to look for a place to park the car that is closest to the supermarket entrance in order to save a few small steps. Or have a home delivery service that allows us, without any effort, to receive everything we want.

And then, let’s be honest, we repeatedly gave in to the couch call when we had planned a little sports session.

But to get back to my point, beyond these examples, is there any scientific evidence that explains why we are lazy?

The Law of Least Effort

A lot of research shows that humans naturally seek to minimize their energy costs.

Imagine the following situation: A researcher puts you on a treadmill without any particular instructions, except not to fall.

The belt starts to move, you start to walk. The speed of the belt increases slowly. At some point, you start running.

If you are not sure why you spontaneously switched from walking to running (even if you can walk at a fast pace and still not fall), the researcher can explain it to you:

This transition, which occurs when the speed of the belt is between 6 and 10 feet per second, reduces the energy cost associated with the movement.

If you had continued to walk, the energy cost would have been much higher than the cost of running. By running, you have minimized your energy expenditure.

In 2015, a Canadian study confirmed this tendency of human beings to optimize the energy cost of walking.

In this study, the researchers used a motorized structure on the lower limbs of the participants. This exoskeleton made it possible to apply more or less resistance to leg movements when walking.

Participants quickly adapted to these resistance levels and converged on the most energy-efficient walking frequency.

So, are we lazy or efficient?

For the authors of the studies mentioned above, the results provide physiological evidence of our inherent tendency towards laziness, or rather, we should say, efficiency.

But this efficiency program is deep written in our brains and often drives us to drop a physical activity altogether. This is because our unconscious mind doesn’t see the benefits of, for example, going to the gym or taking a long walk.

It is the conscious part of our brain (specifically the pre-frontal cortex as we will discover) that is responsible for taking real action. It is at this moment that you are behind the wheel, so to speak.

What is a lazy person?

Laziness is therefore where we do not override the propensity of our bodies towards efficiency and saving energy, even if we really should (and know it!).

The fact of not being able to overcome our bias towards exerting the least effort could explain the results of many previous studies showing a paradoxical gap between the intention to be productive and actually doing the work.

Which leads us to an important question: what is it in our brains that makes us unable to transform this intention into real action?

Is Our Brain The Main Cause For Laziness?

The Escalator Paradox

In an article published in Sports Medicine, It was hypothesized that the paradoxical gap between intention and action results from a struggle between our reason, on the one hand, and an automatic tendency towards minimizing effort, on the other.

To illustrate this paradox, the most often used example is people taking an escalator to get to the gym.

This behavior is difficult to understand and seems contradictory, unless something in our brain unconsciously pushes us to take the escalator.

How Does Your Brain Manage To Make You Lazy? (why is it so hard to get off the couch)

In order to study the brain’s involvement in laziness, researchers tested 29 young adults who wanted to be physically fit but were not necessarily able to do so.

The experiment consisted of a simple task: participants had to take control of an avatar on a computer screen using the keys on the keyboard, while sixty-four electrodes placed on their skulls were used to read and record the electrical signals produced by their brains.

More precisely, participants were asked, in a first step, to bring this avatar as quickly as possible closer to images representing physical activity (running, cycling, swimming…) and moving it away from images representing sedentary activity (reading, watching TV…).

In a second step, participants had to do the opposite; move the avatar towards images representing physical inactivity and away from those representing physical activity.

The reaction times recorded when participants performed the two tasks show that they were generally quicker to avoid images of sedentary life than images of physical activity. These results confirm that participants did intend to be active.

However, the electrical signals collected from the brain told a different story. Indeed, to move away from images of inactivity, the brain had to use more resources; that is, it had to increase its work intensity.

One of the areas of the brain that was more involved in avoiding pictures representing inactivity was located in the front of our brain and was known for its role in conflict management.

Researchers also saw the activation of another region of the frontal lobe, this time associated with the inhibition of automatic behaviors.

Which explains that, in this particular experiment, the conflict in question opposes two ideas:

  • The desire to move away from images representing an inactive lifestyle
  • The natural attraction towards images associated with low energy expenditure

In other words, moving away from an inactive life requires silencing our natural inclination for minimizing energy expenditure.

Finally, unlike the results obtained on participants’ reaction times, their brain activity did not vary significantly relative to how hard the physical activity represented in the images is. This means that the brain mechanisms that prevent us from exercising are at work, regardless of the level of activity we plan to do.

These automatic brain-operated mechanisms could explain our difficulty in adopting an active lifestyle and, consequently, the failure of public health policies to contain the physical inactivity pandemic.

Is There Such a Thing As a “Lazy Gene”?

In addition to the experiments on brain involvement in laziness (described above), genetic results are showing that this push towards minimizing energy expenditure would not only be embedded in our brain but also our genes.

In 2013, a British study of more than 700 pairs of identical and fraternal twins (mono and dizygotic) showed that the time spent in sedentary activities was much more variable between fraternal twins (who share half their genetic heritage) than between identical twins (who share almost all their genetic makeup).

Using this observed difference in behavior, the researchers estimated that about 30% of our sedentary lifestyle would be explained by our genetic makeup.

Another study conducted the same year in the United States classified mice according to their amount of spontaneous physical activity (number of wheel revolutions per day).

The researchers in this study then separated the active mice from the inactive mice and allowed them to reproduce over ten generations.

They observed that over generations, the active mouse line became more and more active, while the inactive mouse line became more and more inactive.

Also, the latest generation mice from the inactive line spent ten times less time running than the mice from the active line.

Most significantly, in a follow-up study, these researchers showed that this difference in physical activity was explained by a difference in the maturation of neurons in the accumbens nucleus, a region of the brain that plays an important role in the reward system and motor activation.

In short, all these experimental results show that differences in physical activity levels could well be embedded in our brains as well as our genes.

Why Would We Inherit A Tendency For Laziness?

The tendency towards minimization of effort may be the result of evolution. However, the tendency to minimize our energy costs has negative consequences on our health.

In 2016, a quarter of the world’s population, or about 1.4 billion people, were physically inactive, and this unhealthy lifestyle is killing us.

According to the World Health Organization, 3.2 million deaths worldwide each year are due to lack of physical activity, which represents one death every 10 seconds.

Yet, in the time of our ancestors, minimization of energy expenditure made it possible to increase the chances of survival and reproduction.

For example, a recent study comparing the metabolism of hundreds of shellfish species shows that the basic energy expenditure of these shellfish has played a fundamental role in the extinction or survival of their own species. Species with lower metabolism were more likely to survive than those with higher metabolism.

Closer to humans, a study shows that the transition from quadruple to bipedalism (walking on two feet) is associated with a significant decrease in the energy cost of walking, which provides an evolutionary advantage by reducing the cost of travel associated with seeking food, shelter, or escape.

So, are we programmed to do nothing all day – to be lazy?

The answer to this question is clear and straightforward: no.

In addition to minimizing energy expenditure, movement also played a fundamental role in the survival of our ancestors. Without the ability to move, it is impossible to search for food or shelter, to fight sexual competitors, or to escape predators.

Moving is also the cornerstone of major developmental processes, whether cognitive, emotional, or social.

When I think back to my son spending so much time in the park, I realize that he is thinking, having fun, developing and playing with other children.

Human beings have evolved to be active, but that’s not the end of the story. Living organisms that survived the natural selection process are those that were able to be active but were also able to minimize their energy expenditure.

Combined, these two vital abilities (minimizing energy expenditure, and constant movement) allowed them to find food or partners, increasing their chances of survival and reproduction.

My boy’s tendency to avoid unnecessary effort may, therefore, well be a legacy of evolution. We are not programmed to be lazy but to be efficient: to carry out an action with the minimum energy expenditure.

Should You Blame Your Laziness on Your Brain?

Even if you inherited a propensity for saving your body’s energy from your ancestors, don’t celebrate just yet (and blame your laziness on your brain). Because they have also given you a particularly effective tool to resist it: the pre-frontal cortex.

Over the course of evolution, the volume of this area in front of your brain, and just behind your forehead and eyes, has become increasingly big. This increase in size is likely related to an increase in its use and the number of connections made with other regions of the brain.

The pre-frontal cortex plays a key role in many high-level cognitive functions such as language, memory, reasoning, social functions, and impulse control.

In a study involving 105,206 participants from 21 European countries, researchers showed that participants’ cognitive resources are correlated with their level of physical activity.

This result could mean that these cognitive resources are necessary to combat our tendency to minimize effort and thus increase our level of physical activity.

Another study showed that these cognitive resources also limit the negative impact of an environment that encourages physical inactivity, such as unsafe neighborhoods or areas that do not include businesses within a reasonable walking distance.

In other words, being active begins with activating your brain, refusing to be trapped by your innate lure towards sedentary living.

When you are faced with the choice of stairs or escalators, you must activate your brain’s conscious decision-making process to avoid being one of the 85% who choose the escalator.

By “activating your brain’s conscious decision-making process”, what we mean is:

  1. Remember what you know about our natural tendency towards inactivity in order to save energy
  2. Deliberately choose to opt for conscious and voluntary functioning instead of automatic and unconscious behavior

In Summary

The law of the least effort was engraved in our genes and our brain during evolution as a result of the natural selection process. This law is expressed in particular by a tendency to minimize physical effort.

To counter our automatic tendency towards this minimization, our brain must mobilize more cognitive resources.

It is our choice to manage between our body’s tendency to save energy, and our intentions to be active.

This conclusion may take away an excuse for missing your last gym session, but look on the bright side, it’s always more enjoyable and rewarding to be defined at your very core as efficient, rather than lazy.


Jim Miller

Jim spent his twenties trying tounderstand how our primitive minds get in the way of self-growth. He has a lot of interesting ideas about human psychology that he doesn't hesitate to share when opportunity presents itself.

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Jim Miller

Jim spent his twenties trying tounderstand how our primitive minds get in the way of self-growth. He has a lot of interesting ideas about human psychology that he doesn't hesitate to share when opportunity presents itself.

Subscribe to our newsletter

Be the first to receive the latest articles and exclusive offers on our products directly in your inbox

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