Germans have an average IQ of around 100 (it used to be 105 before immigration). Turks have an IQ of 85-90. If you are not biased, you can clearly see these differences in everyday life. With a few exceptions, the intellectual achievements of fellow citizens of Turkish origin tend to be rather low. The situation is different when you look at migrants from high-IQ countries, such as China (who have an IQ of 104). These children often achieve amazing results, for example in the International Science Olympiads. The US is actually only able to achieve top places in the Math Olympiad thanks to Chinese migrants. Almost the entire US team consists of people with a Chinese background. Look at this picture of the US-Team for 2023 if you want to know, what I mean: https://maa.org/wp-content/uploads/2024/05/Screen-Shot-2024-...