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Almost all people react emotionally to tickling. However, they don’t laugh when they tickle themselves.

For most people, the reaction to tickling is typical – it’s a pleasant feeling, but excessive nerve excitement and loss of control can cause irritation. Still, for some reason we can’t feel the same way when we tickle ourselves, LiveScience writes.

The answer to this question is that the brain already knows about the expected feeling of tickling and downplays its manifestations.

“It’s because the brain is always predicting into the future. Brains are not just reactive; they are trying to guess ahead at what’s going to come next,” said Stanford University neuroscientist David Eagleman.

According to scientists, every time a person performs an action, the primary motor cortex, the part of your brain responsible for initiating the message, sends a copy of the command to many areas of the brain to prepare for the sensory information that is to come from the human action.

For example, when a person wants to pick up a pencil, the brain sends a message to the hand and fingers. However, it doesn’t just send messages to the muscles that will generate this movement, it also sends copies to the somatosensory cortex, the part of the brain that processes incoming sensory information, and to the visual cortex, which is responsible for processing vision.

Konstantina Kilteni, a neuroscientist at the Karolinska Institute in Stockholm, explains that the brain uses the signals it sends to the muscles to predict future action.

Kilteni runs the Somatosensation & Gargalesis lab, which is called the Touch and Tickle Lab. Using brain imaging techniques such as fMRI and magnetoencephalography, she and her team are investigating whether the brain perceives a touch made by oneself differently than a touch of someone else.

According to the neuroscientist, people constantly perceive the intensity of their own touch as weaker than external stimuli. And it’s not just a perception. Neuroimaging confirms that the brain reacts less strongly to self-generated touch.

Instead, people are more attentive to external stimuli that are perceived by all the senses, because understanding them can be crucial for survival, experts explain.

That’s why tickling oneself does not work. After all, the brain knows about our actions in advance and sends signals that nothing important or threatening is happening. However, if it’s someone else, the sensation intensifies. The brain is not prepared and the tickle works. After all, tickling requires a surprise, scientists say.

Still, there are some exceptions. For example, people with schizophrenia have difficulty recognizing what they initiated from what they didn’t. They often fail to predict their movements and subsequent sensations, so tickling themselves surprises them.