Brief: A season-of-birth effect in music preferences

The GSS asks people what their astrological sign is, allowing us to investigate season-of-birth effects. For instance, babies born in inclement weather may have different developmental shocks than summer-born babies do, and that could influence how they turn out as adults.

I looked for a season effect in personality traits, and although people are not uniformly the same across all birth months, there is either a very tiny pattern or larger but seemingly random differences. Nothing with a clear rising-and-falling pattern of great amplitude. For those things, season-of-birth at best plays a very small role in how you turn out.

But I did find a strong effect for whether you love classical music ("birth month" is the month that has the majority share of days belonging to a zodiac sign):


There are equally tall peaks among those born in February and those born roughly half a year later in July. There's a local trough among April births and a global trough among those born roughly half a year later in November. Maybe having weekly data would help us better resolve what the period of the cycle is, but it looks like half a year (5 months between peaks and 7 months between troughs). It can't be a particular type of weather that makes someone really dig classical music, since February is winter and July is summer. So perhaps the mechanism has to do with being exposed to extreme weather vs. mild weather as an infant (winter and summer vs. spring and autumn).

Also notice how wide the differences are: 10.9% for Scorpios vs. 21.2% for Cancers and 20.7% for Aquariuses -- nearly double. Imagine if season-of-birth doubled your chance of turning out some other interesting way, from 1 in 10 to 2 in 10 -- say, going to college or developing some disease. These are not small effects.

I stress that this is probably not mediated by intelligence or general personality traits like an openness to art or a taste for excitement, as these don't show this pronounced seasonal pattern. Nor do relevant behavioral variables like whether you went to a live performance of classical music or opera, whether you visited an art museum, whether you attended a dance performance, etc. Presumably those draw many other people in addition to those who are possessed by their love for classical music.

Music touches us in a strange way; it's not like literature that taps directly into our brain's language module, nor is it like visual art that taps directly into our visual center, face recognition module, and so on. It is very hard for music to tell a narrative as clearly as literature or a painting can. At best it can provoke a connected sequence of emotions. And unlike other music forms, classical relies heavily on harmony. Keeping track of the separate but interacting layers of melody is probably something our brain is not designed by natural selection to do; it's like following a conversation between four people who are talking at the same time. Perhaps it takes a certain degree of screwiness in the brain to really get that appeal of classical music, and that enduring extreme weather as a newborn helps that happen.

GSS variables used: zodiac, classicl