When did intelligence develop?

The development of human intelligence

The age of the "rational man" Homo Sapiens is estimated to be around 150 thousand years. Little is known about the beginnings. About 11-14 thousand years ago people began to settle down after a cold spell. Living together in groups made it possible to develop ideas together and to disseminate existing knowledge. This was probably the most crucial step in human evolution. The last 5000 years before Christ were shaped by comparatively great developments, e.g. ceramics, the wheel, cuneiform writing, glass, mechanical calculating devices, pulley blocks, the first automatic machines, devices using mechanical steam pressure and paper were invented. The speed of technical developments since the beginning of industrialization in the 18th century has been even more rapid. Discoveries and inventions are changing the world at a speed unprecedented in previous human history. An unbelievable expansion of human knowledge and its availability, the use of mechanical power from the steam engine to atomic energy, limitless communication and mobility are rough keywords.

But is that really why people today are more intelligent than their ancestors?

Whoever reads Plato's writings from the 5th century BC Reads, finds here a justified objection to the thesis of the increase in intelligence. Thousands of years ago there were highly intelligent people whose ingenuity we still admire today. I cannot say whether the inventor of the light bulb, Thomas Alva Edison, was smarter than Plato. But he had the advantage of being able to fall back on a broad, learned knowledge even before his invention, of which no one suspected anything in Plato's time. Our technical revolution is not evidence of growing intelligence, but an expression of the development of knowledge building on one another, as well as increasing networking and division of labor.

The superiority of human intelligence

In order to better understand the outstanding properties of human intelligence, comparing animals is helpful. What distinguishes people? Dogs can dream. Behavioral research has shown in experiments that ravens can forge plans to solve complex mechanical tasks. Orangutans, which were taught to play the memory game on a touch screen, solved all tasks with a speed and reliability that was far superior to most people. You have an enormous image memory and ability to react. We are amazed at the extent to which animals can communicate, the more researchers succeed in deciphering them. From a long list, these are just a few examples that support the following scientific thesis:

The superiority of humans over animals consists less in their intuition or cognition than in the ability to store knowledge, to pass it on and to solve problems together. The "swarm intelligence", the ability to share a task arbitrarily in order to solve it together, is probably the most important.

No one today is able to manufacture or even understand a car on their own. The automotive engineer may be able to explain the engine but understand nothing about the navigation computer. And the engineer no longer oversees the production of all individual parts of an engine, beginning with the material manufacture. The non-expert is happy when he understands how to fully operate his car.

Intelligence measurement and research

Psychologists have developed intelligence tests to measure and compare human intelligence. Intelligence is seen as the sum of different abilities. These include language comprehension, reasoning, memory, and processing speed. The result is summarized in a so-called intelligence quotient IQ. The test value indicates the relation of the measured performance to the average, hence the quotient. An IQ of 100 corresponds to the average. From a value of 130 one speaks of a giftedness. A test that is often used today is the "Hamburg-Wechsler Test", which was developed in 1949. Because this test has been around for a long time, it is possible to compare the results of the test over longer periods of time.

The groundbreaking discovery of James Flynn

This is exactly what philosophy professor James Flynn did in the 1980s. He compared the results of studies on intelligence measurements from a total of 35 countries over several decades and came to an astonishing result: In all western industrial nations, the IQ has increased from generation to generation, with the difference of 5 to 25 points being quite considerable. This phenomenon, which after careful examination gained general recognition, was finally named "Flynn effect" after its discoverer. As indisputable as the effect is, its causes are unclear. The performance measured in an intelligence test can generally be trained. Those who have to learn a lot by heart will improve their memory, those who play chess more often will improve and even solving math problems can be trained.

A general, good and continuous school education will thus have a positive influence on the test results. In addition, the economic development of the post-war years together with the avoidance of malnutrition, better medical care and better hygiene conditions are used as reasons. The Fynn effect is probably the sum of healthier living conditions compared to previous years and better schooling.

The reverse Flynn effect

Long after Prof. James Flynn left the profession, researchers at the University of Oslo began to compare the IQ test results of the "post-Flynn era". Numerous studies in Western Europe and Australia followed. The surprising result: Since 1994, the IQ has been falling by an average of 0.25 to 0.5 points per year. The phenomenon has been dubbed the "reverse Flynn effect" and has sparked lively debate among scientists.

Some scientists have doubts that the worse test results are synonymous with negative intelligence development. The result of a test also depends on what we measure and how. If one were to "modernize" the test content, different results could be achieved. But then these would no longer be comparable with older ones.


James Flynn gave his own opinion on the study results as follows:

"The biggest change I've noticed over the years is the disappearance of sophisticated books ... The children get lost in computer games. And as good as they get at playing, they get bad at thinking logically." His students, Flynn observed, were finding it increasingly difficult to read Schopenhauer. (Quote from "Zeit" from March 28, 2019)

Only those who can concentrate can learn well. In the western industrialized nations, attention deficit disorders (ADHD) and disorders from the autism spectrum are becoming more and more common.

The question also arises as to whether our schools can counteract this development or whether the development of our education system is even part of the problem. Finally, digitization also influences our learning behavior. If you don't have to remember anything, you no longer train your memory. If you are constantly distracted, you will not learn to concentrate. One could exaggerate: Anyone who lets an artificial intelligence think for themselves becomes stupid themselves. An aspect that we shouldn't forget when it comes to the digital project in our schools.

Of course, digitization and networking offer enormous opportunities for global "swarm intelligence", knowledge acquisition and further technical development. As with everything in the world, there are also risks and side effects, especially for the individual, to be considered.


About the author

Dr. med. Roger Agne
Head of Internal Medicine
Dill clinics

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