Why do we laugh when we are tickled?

|| Editorial staff of El Periodiquito

Tickling is a clear example of mixed feelings. When someone tickles us, we can’t stop laughing, but at the same time, we wish they would stop tickling us. Deep down, they are annoying. But then, why do we laugh? In fact, that question is not the only mystery surrounding tickling.

It is also curious that we cannot cause them to ourselves. Or even that most people laugh more when they are on the right side. All this seems to have an evolutionary explanation. It is not certain, but there are certain hypotheses about it. In any case, before getting to that point, let’s see which areas of the brain are involved in them. Knowing them is very revealing with respect to the evolutionary explanation of their appearance.

Tickling is not funny In 2013, a team of scientists from the University of Tübingen in Germany conducted a study comparing the effects of hearing a joke or being tickled. Since both make us laugh, you might expect the same areas of the brain to be activated. However, what they found was far more surprising.

Thirty people participated in the experiment, and their brain activity was analysed using magnetic resonance imaging during the two actions mentioned above: jokes or tickling. In both cases, an area known as Roland’s operculum was activated. This is a region that controls vocal and facial movements associated with emotions. This is the case with laughter, of course. But what emotions generated this laughter? In the case of the joke, it was the area that lit up the most, but during tickling, activity in the hypothalamus also became very important.

This is where the primitive desire to escape from danger is generated. That feeling of alertness that we all have innately and makes us flee before things get ugly. This need to flee is closely associated with anxiety, since all its symptoms, from palpitations to muscle stiffness, are associated with the body’s response to flee or fight when faced with a warning signal.

According to the scientists who conducted that study and many others who have analyzed it since, their discovery helps explain the possible evolutionary origin of tickling. Perhaps it was a way of showing submission to a competitor or a predator. If we turn and become violent when faced with an uncomfortable sensation like tickling, we can generate more violence on the other side. But if we laugh, we show that we are totally submissive.

Of course, this doesn’t make much sense today. However, if in the past you had to fight another hominid to decide who got the last cave, showing submission could be the difference between living or dying. But then, are they painful? There are two types of tickling. On the one hand, tickismesis is a slight irritation caused by contact in a sensitive area. This is what happens when we are lightly tickled. We can also feel it from the brush of a hair or even the walking of an insect.

On the other hand, gargalesis occurs when we are subjected to much greater pressure in sensitive areas. For example, when we press with our fingers on the sides of the torso, a little above the hips. Both are actually painful sensations, especially the second. In fact, the signals generated by this pressure on the skin, more or less pronounced, travel along the same nerve pathways as those that cause pain. The hypothalamus also processes information from a stimulus that may be painful.

So, in reality, a sensation of pain is being stimulated all the time. If we laugh, it is because of this evolutionary impulse to be submissive. Why can’t we tickle ourselves? There is no point in laughing at our own tickles, because we know that we are generally not a danger to ourselves. We try to tickle ourselves to make ourselves laugh, but we fail because we don’t have this evolutionary need to laugh. Now, how does our brain know that we have exerted the pressure? The answer to this question lies in a phenomenon known as corollary discharge.

When we make any movement, our brain orders the body part in question to move. But at the same time, another signal is sent. A kind of acknowledgement that guarantees that the signal has been sent correctly and that it was our brain that sent it. This is mediated by the cerebellum and is important in cases such as tickling. By the time our brain receives the signal that we are pressing the skin, it has also received an acknowledgement that it was us who decided to make the movement.

The Roland operculum response is therefore suppressed. There is no need to laugh. One sign that this is true is that people with schizophrenia or traits associated with the illness can tickle themselves. These people are known to have defects in the corollary discharge system. This is why they sometimes feel that what they are doing is being done by someone else. And this is why they can laugh at their own tickling.

Are you more ticklish on one side than the other?

A curious thing is that there are many people who claim that they are more ticklish on one side than the other. Specifically, it seems that they are more ticklish on the right side. It may seem strange, but the truth is that it is a phenomenon that has been scientifically studied. It is believed that it may be related to differences in the way in which each hemisphere processes emotions. However, more research is needed to know for sure. What is clear is that if we laugh at tickling, it is not because it is funny, but to save our lives. Okay, this now sounds very dramatic, but in the past it made perfect sense.