There are a lot of scammers, people who simply took a three-month course, tarot card readers or astrologers who say they're professional psychologists.
The inventions and innovations of the Sumerians were adopted by other Mesopotamian cultures by the 7th century BCE, and Babylon became famous for its astronomers and astrologers.
Astrologers are people who say they can find out about your personality, and maybe your future, by analysing the position of stars and planets the day you were born.
Lest any astrologer reading this result get cocky, Dr Cajochen does not believe that what he has found is directly influenced by the Moon through, say, some tidal effect.