A handshake can tell you a lot about a person's life. Scientists measured grip strength in tens of thousands of people over fifty in three different places: the US, China and Europe. They wanted to understand why some people have stronger hands than others, and what role education plays in that.
It turned out that education works like a lever. The longer a person studied, the stronger their hand usually is. But the length of that lever depends on the country. In Europe it is the longest: the strength gap between people with high and low education reaches 3.48 kg in men, about the weight of a small cat. In China the lever is shorter: for men the gain is only 1.84 kg, and for women 0.79 kg, less than a pack of butter. Yet the gulf between the most educated and the least educated Chinese turned out to be the deepest. So in China education gives less strength to each individual, but the gap between groups is huge, especially for women.
So simply giving someone an education is not enough. The lever needs to work the same for everyone, regardless of gender or a country's history. Otherwise some will shake hands firmly, while others can barely squeeze their fingers, even though they studied for the same number of years.
The difference in grip strength between European and American men with high education reaches 3.48 kg, comparable to the weight of a small cat.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.