Therefore, the brain has difficulty counting beyond four

The human brain uses one mechanism to judge four or fewer things, and another mechanism when there are five or more, the study recently published in the journal Nature revealed.

This discovery could help brain researchers, psychologists and other professional groups understand the basic elements that make up the brain’s thoughts and how they are formed.

A rare opportunity for experimentation

German researchers had a rare opportunity to measure the activity of individual neurons in the brains of people who were awake.

All 17 people were scheduled to undergo surgery to treat epileptic seizures at the University Hospital in Bonn, and thus had already had tiny electrodes inserted into their brains.

Before the patients underwent surgery, the researchers showed them images containing a number of dots between zero and nine for half a second. Next, they asked the patients whether the image showed an even or odd number.

As expected, participants were most accurate when they saw four or fewer dots.

Speech systems in the brain

Researchers already knew from previous studies that there are specialized neurons associated with specific numbers. Some elicit impulses primarily when they are presented with one object, others when they are presented with two objects, and so on.

The participants’ neural activity showed that neurons specialized in sending information about four or fewer objects responded very specifically to their specific number. In contrast, neurons specialized for numbers between five and nine responded strongly to their specific number, but also to numbers close to it.

For example, neurons specific for the number three respond only to that number, while neurons targeted for the number eight respond to eight, but also to seven and nine.

According to the researchers behind it, the difference between the two types of neurons indicates this the study That the brain has two different “digital systems.”

It also explains why people make more errors when trying to estimate a larger number of objects.

“The greater the specific number of neurons, the less selective they are in their signals,” said co-author Andreas Nieder, a physiologist at the University of Tübingen in Germany.