The positive impact on human intelligence of doing crossword puzzles and solving logical problems was once again confirmed by research by Dublin scientists. The experiments involved a group of 70-year-old Irish men undergoing a brain training program. At the end of the study, older people showed improvements in their mental abilities. During classes, the frontal lobes of the brain, which are responsible for a person’s ability to self-organize, make decisions, and attentiveness, worked most intensely in pensioners. According to scientists, “aerobics for the brain” activated the production of serotonin, which leads to the formation of new blood vessels that supply nutrition to the brain.