By Alejandra Martins. BBC News World
As you read these lines, how is your body positioned? Are you standing upright or hunched over? And is your face relaxed or frowning?
Our posture and our face send important signals to our brain, and it is information to which our brain responds, explained Spanish neuroscientist Nazareth Castellanos, researcher at the Nirakara-Lab Laboratory, extraordinary chair of the Complutense University of Madrid.
"If I have an angry face, the brain interprets this face as one of anger and therefore activates anger mechanisms," Castellanos stated.
Similarly, "when the body has a posture typical of being sad, the brain begins to activate neural mechanisms typical of being sad."
Our brain interacts with the rest of the body in far more ways than previously thought. "We don't just have five senses, we have seven," the scientist pointed out. And the five most well-known senses—taste, smell, and so on—"are the least important to the brain."
How did you come to investigate the relationship between posture and the brain?
I began to rethink neuroscience after spending 20 years researching only the brain. It seemed strange to me that human behavior was based solely on one organ, the one in the head.
I had previously begun studying the influence of organs like the gut on the brain. And I thought, it can't be the same for the brain if my body is hunched over as if it's upright. So I started investigating, seeing what the scientific literature said; I discovered things that seemed absolutely astonishing to me, and I thought, everyone needs to know this.
Could you then explain why posture is important and how it influences the brain?
The important thing is to understand that neuroscience now recognizes that we have seven senses.
At school we've always been taught that we have five senses—smell, sight, hearing, touch, and taste—which are the senses of exteroception, that is, the external world. And this is very symbolic, because until now science has been more interested in studying the relationship between human beings and the external world.
Now, neuroscience has been saying for about five years that we need to expand on this. We don't just have five senses, but seven. And it turns out that the five exteroceptive senses—hearing, etc.—are the least important. The number one, the most important sense, is interoception.
What does interoception mean?
It's the information that reaches the brain about what's happening inside the body. What's going on inside the organs.
We're talking about the heart, breathing, stomach, and intestines. It's the number one sense because, of everything that happens, it's what the brain will give the most importance to; it's a priority for the brain.
And number two in priority is the sense of proprioception, the information that reaches the brain about how my body is on the outside, the posture, the gestures and the sensations that I have throughout my body.
For example, the sensations in your stomach when you get nervous, or a lump in your throat, or the heaviness of your eyes when you're tired. Proprioception is the second most important sense. And then come the five.
What does it mean that interoception and proprioception are the first and second senses for the brain?
It was already known that the brain needs to know the state of the entire body, but previously it was thought that this was passive information. The change now is that this is a sense. That is, a sense is the information that the brain receives and to which it must respond.
Depending on what is happening, the brain has to act in one way or another, and this is the big change.
In what part of the brain do we perceive our posture or gestures?
In our brain there's an area that's like a headband, like the one you wear to keep your hair back. This is called the somatosensory cortex, and that's where my body is represented.
This was discovered in 1952 , and the theory was that larger areas of our body have more neurons in the brain. Therefore, it was thought that the brain dedicated many more neurons to the back, which is very large, than, for example, to my little finger.
But it was discovered that no, the brain gives more importance to some parts of the body than to others, and what the brain gives more importance to of the whole body is the face, the hands and the curvature of the body.
So my little finger has about a hundred times more neurons dedicated to it than my entire back, than my entire leg, because our hands are very important to us. Notice that when we speak, we're using our hands; we're activating those areas of the brain.
How do facial gestures influence the brain?
The brain attaches tremendous importance to what happens on the face.
Here we've seen some very important things. For one thing, it was observed that people who frown—and this is something we do a lot with phones that have small screens—are activating an area related to the amygdala. It's a part of the brain located in deeper areas and more involved in emotion.
When I frown, I'm activating my amygdala. Therefore, if a stressful situation arises, I'm going to become more agitated and react more strongly because that area is already primed. The amygdala, which is shaped like an almond, is an area that becomes activated and enlarged when faced with a stressful situation.
So it's an area that's best kept calm.
But if it's already activated, when a stressful situation arises it will become hyperactivated, and this will cause me to overreact.
Trying to soften this part, the frown, deactivates our amygdala a little, it relaxes.
In a talk, you mentioned a fascinating study with pens that shows how frowning or smiling changes the way we interpret the world. Could you explain this study to us?
Besides the muscles around the eyes, the second most important part of the face for the brain is the mouth. We're not aware of its power; it's impressive.
So what the studies did, to test the facial feedback hypothesis, was to take a group of people and put a pen in their mouths.
First, they had to hold the pen between their teeth, simulating a smile, but without actually smiling, which was the important thing. Then they were shown a series of pictures and had to say how cute they found them. The more cute the pictures seemed, the more they thought they looked.
But when they held the pen to their lips, simulating an angry face, the same images no longer seemed so pleasant. This is a study from the 1980s, but many, many studies have been done since then.
It has been shown, for example, that when we see smiling people we are more creative, our cognitive capacity increases, and the neuronal response to a smiling face is much stronger than to a face that does not smile or an angry face.
The insula, one of the brain areas most involved in identity, is activated when we see someone smile or when we smile ourselves. Smiling is not laughing; it's different. This illustrates the power a smile has over us, because the brain, as we've mentioned, dedicates a large number of neurons to the face.
How does the brain respond when we smile or frown?
As we have said, proprioception - which is the information that reaches the brain about how my body is and specifically my face - is information to which the brain has to react.
If I'm sad, angry, or happy, my face reflects it, but the reverse is also true. If I have an angry face, the brain interprets "this face is typical of anger, therefore I activate anger mechanisms," or "this face is typical of being calm, therefore I activate mechanisms of being calm."
In other words, the brain is always seeking what is called mind-body congruence.
And this is interesting because what happens if I'm sad, angry, or stressed, and I start to put on a relaxed face? At first, the brain says, "This doesn't add up; she's nervous but she's putting on a relaxed face." And then it starts generating something called mood migration. The brain says, "Okay, so I'll try to match the mood to the face."
So, look what resources we have.
You also mentioned another aspect of proprioception: body curvature. These days, with cell phones, we're often hunched over. How does this affect the brain?
The brain - and this is a discovery from three months ago - has an area that is dedicated exclusively to seeing my body posture.
What we've seen is that there are body postures that the brain associates with an emotional state. If I, for example, move my arms up and down, the brain doesn't register that raising a hand is something emotional, because we don't usually do it, right?
However, slouching is a sign of sadness, and it's true, when we're feeling down, we slouch. Lately, we've all adopted slouching postures because we spend eight hours a day in front of a computer, among other things.
Is this what you're referring to in a famous study you mention in your talks, the one about the computer?
When we have a hunched posture, it affects our emotional perception of the world and our memory. This is where a famous experiment was conducted in which people were shown a laptop at eye level, and a series of words appeared on the screen.
Finally, they close the computer and tell them, "Tell me how many words you remembered." And they did the same thing, but placing the computer on the floor in such a way that it forced people to bend over.
What was observed? That when the body was in a downward, hunched posture, people remembered fewer words; that is, they lost memory capacity and remembered negative words more than positive ones.
In other words, just as when we are sad, we are not as cognitively agile and we focus more on the negative, when the body has a posture typical of being sad, the brain begins to activate the neural mechanisms typical of being sad.
So, what does science ultimately tell us? Well, it's not that we have to be this way or that way, but rather that throughout the day we should be more aware of our own bodies and correct the paths we've been taking.
I, for example, observe myself a lot and I discover every now and then that I've started slouching again. So you correct it, and over time you gradually acquire less of that habit.
But if you don't have that ability to observe your own body, you can be like that for hours and not realize that you are like that.
Nazareth, how then do we train ourselves to listen more to our bodies? You often say that the body doesn't shout, it whispers, but we don't know how to listen to it.
I believe the first step to understanding our bodies is learning to observe them. And studies tell us that a large part of the population has very low body awareness.
For example, every time we feel an emotion, we feel it in some part of the body; emotions without the body would only be an intellectual idea.
There are studies that ask people, "When you're nervous, where in your body would you locate that sensation?" Many don't know the answer because they've never stopped to observe their own bodies.
So the first thing is, throughout the day, to stop and observe, how is my body? And when we feel an emotion, stop for a moment and say, where do I locate it? How does my body feel at this moment? That is, to do much more body observation.
And does this body awareness help with difficult emotions?
When I get nervous, for example, I feel a knot in my stomach or a lump in my throat. My brain senses all of that; it receives it. When I'm aware of those sensations, the information that reaches my brain is clearer, and therefore, my brain is better able to distinguish one emotion from another.
In other words, one thing is that almost unconscious whisper, and another is turning it into words.
And we do this with awareness, which is also an ally in managing emotions. Because when we're immersed in an emotion, whatever it may be, if we stop at that moment and shift our attention to the sensations in our body, it brings us a lot of relief.
It's one of the ways we relax, to slow down that whirlwind we get caught up in when we experience an emotion. This is called body awareness.
Back in the 1990s , Antonio Damasio , the great neuroscientist of our time, spoke to us about the benefits of this somatic marker. He conducted many experiments showing that people with greater body awareness make better decisions.
In my opinion, this is because it's not that the body tells you where you have to go, but rather where you are. And if we're in a complex situation with emotions involved, and I myself don't even know where I am or what emotion I'm experiencing, it's much harder for me to know where I need to go.
Emotions are very complex and are usually intertwined. Identifying an emotion through mental analysis alone is more difficult than by observing my own body.
But of course, for that we've had to train ourselves, observing our body's sensations throughout the day: when I'm tired, when I'm happy, when I'm more neutral, when I'm angry, when I'm overwhelmed. Where do I feel it? This helps us a lot to get to know ourselves.
Slouching makes us breathe worse, could you talk to us about breathing and the brain?
Breathing is an ally that we have completely in our hands, but we don't know how to breathe.
Posture and breathing are closely related. If you take care of your posture, you take care of your breathing. Neuroanatomy of respiration has shown that breathing influences memory, attention, and emotional regulation. But be careful if it's nasal breathing, if you're inhaling through your nose.
If we breathe in through our mouths, and a large part of the population are mouth breathers, we don't have as much capacity to activate the brain.
The brain needs rhythms, and breathing is one of the pacemakers our brain uses to regulate the neurons' electrical activity. Breathing through the mouth is like a weakened pacemaker. Inhalation must be through the nose.
When we inhale, for example, the moment when we have the most memory is the moment when we are inhaling through the nose; at that moment the hippocampus is activated.
If someone says something to you, a single word, at the moment it coincides with an inhalation, it is more likely to be remembered than if they say it to you when you were exhaling.
This tells us something very interesting: slow breathing. We normally breathe very fast.
How important is slow breathing?
We have just published a scientific study on the power of slow breathing as an analgesic in cases of chronic pain due to discopathy (deterioration of the discs between the vertebrae).
And when it comes to emotions, the important thing is that the time it takes us to exhale, to let the air out, is longer than the time it takes us to inhale. Just think how important that is, how many things we can do with our own bodies.
Our body is the instrument through which our life sounds, but it is an instrument we do not know how to play.
We have to learn to know it first, and then to play it.