In our daily lives we constantly look. We see and analyze what we observe through our eyes and, in fact, a large part of our cerebral cortex is dedicated to processing visual data. However, every few seconds something happens that we often do not even realize: we close our eyes to immediately open them again.
In other words, we blink. This action can be forced and even controlled by us if we pay attention to it, but as a general rule it is something we do unconsciously and involuntarily. But why do we do this? Why do we blink automatically?
We call blinking the process by which we open and close our eyelids at a relatively high speed This action is semi-voluntary, so it is possible to voluntarily restrict or provoke it if we wish and pay attention or even cancel it temporarily, but as a general rule its realization escapes our consciousness.
The human being blinks on average about fifteen to twenty times per minute although it does not do so following a fixed temporal pattern but rather it depends on the circumstances.
Causes of flickering
Blinking is produced mainly by the action of the striatum, part of the basal ganglia (located deep in the brain), and is especially linked to the structure called the globus pallidus. Involvement on the part of the cerebellum has also been found.
Likewise, the autonomic nervous system is also linked to the blink reflex, inhibiting or facilitating it due to the need to activate the body and pay attention to the environment or relax it.
The main reason why we blink is to keep the eye protected and lubricated : since the eyes are the most external organ linked to perception that we have (along with the skin), it is necessary to be able to defend it from harmful chemical substances that may be harmful. Likewise, it requires lubrication to operate constantly and allow clear and clean vision, which is why flickering is allowed.
In addition, the eyes are constantly functioning and receive information continuously, so it is necessary to be able to rest them.
Flicker functions
Blinking is an action that has multiple uses and that can be altered for different reasons. Some of the main functions of flicker are as follows.
eye defense
Blinking allows us to prevent the eye from being damaged by external harmful agents, such as chemicals, physical attacks (we tend to blink when we see something approaching our eye excessively) or even by excessive light level that can damage the inside of our eye.
Lubricate and clean the eye
The surface of the eye is a lens in which images coming from outside will be reflected. One of the functions of the fact that we blink is keep the cornea clean and allow its proper functioning and state of health, since when we blink we spread tears over the entire surface of the eye.
In addition to the eye, blinking relieves specific parts of the brain. It has been proven that the brain decreases the activation of the visual nuclei during the moments in which we blink, which helps us organize visual information
Aspects that alter the blinking rate
There are multiple circumstances that can alter the blinking frequency in humans. They generally have to do with the mood or the level of activation or arousal. Some of the aspects that alter the rhythm or frequency of blinking are the following:
1. Attention, surprise and interest
When something surprises us or catches our attention, we tend to greatly reduce the frequency with which we blink and even stop blinking for a few moments. This allows that we do not lose information about the new situation or what captures our interest.
2. Boredom and disinterest
Most people tend to blink less and more slowly when they are tired and/or bored.
3. Anxiety and nervousness
When we are nervous, stressed or anxious, most people tend to blink continuously and much more frequently than usual
4. Consumption of psychoactive substances
The consumption of different substances with psychoactive effects can also alter blinking, reducing or increasing it.
5. Medical illness or psychological or neurological disorders
It has been shown that different medical diseases or even mental disorders occur with either the alteration or elimination of blinking. In fact, the absence of flicker can be understood as a symptom of a disorder
People who suffer from tic disorders, strokes or dementia or other disorders that cause a progressive degeneration of mental functions usually have altered or even absent blinking.
Alterations have also been seen in subjects with mood disorders (People with depression tend to blink less and more slowly while people in manic phases tend to blink more). Likewise, people with schizophrenia and other psychotic disorders may present these types of alterations.
