Star signs are supposed to dictate your temperament and behaviour patterns based on the positions of various celestial bodies at your time of birth. I’m very sceptical of this reasoning, but while I was examining my reasons for being sceptical I came up with a possible reason that may have an impact on the correlation between _date _of birth and _type _of person.

Birthday parties!

Birthday parties are important to kids, they serve to build social bonds, and also to signal that you are a cool and popular person. As a child your birthday parties either fall within term time, or outside it. This will affect your chances of inviting a large group of your peers to your party. Your party will also be affected by the season; you can’t have a beach party if you are a winter baby, and you won’t have much luck with skiing if you are born in the summer.

Summer parties tend to have a large number of guests and be outside, whereas winter parties tend to be inside have fewer guests because they are more expensive. larger parties may promote weak ties, and small ones develop intimate bonds. This pattern is repeated annually during the formative years.

I think that this may be a strong enough common factor in people’s upbringing that it may shape their personality. A good way to test would be if the correlation between people’s personality test scores and their dates of birth was flipped in the southern hemisphere. Has anyone seen this done?