A psychologist visits Africa with his family on a vacation. One day, although this trip was to get away from work and reduce stress in the office, he decides to conduct an experiment, trying to link foot size to intelligence. As he was nearing the end of his experiment he was startled to find that the people with bigger feet had a larger intelligence! But soon after he found out the reason and went home disappointed at the thought that he found an actual link.
What did the psychologist find out?