Virgle Kent recently observed what many other 20-something men have: the disappearance of cool chicks starting around age 25 or so. We all know that guys are cooler than girls, and so what coolness girls do enjoy must reflect how much guy-type hormone is available to encoolify their brain. Below are some new and old data on tastes in movies as a female ages, and they support the testosterone theory of coolness.
Having shown that under-18 girls are the least likely to dig awful chick flicks -- a certain mark of how cool she is -- I had a hunch and checked out a genre aimed at males: horror. I googled the phrase "best horror movies" and found a website called "best-horror-movies.com," so they must know what they're talking about. The data here are from their list of the 100 greatest horror movies ever.
Same procedure as before: I looked up each movie's rating at IMDb.com and only counted entries that had around 40 or more votes for each female age group (for one, under-18 girls cast 39 votes), and went from the top of the ranking downward until I had 30 movies that met the criterion. I could have gone longer, but the trend was so clear that I didn't bother. The result: for 25 of these 30 movies (or 83%), under-18 girls gave them the highest rating of any female age group. See the Appendix for the significance test. As before, I assume that 18 and 19 year-olds are more like the under-18s than the 20-somethings who IMDb lumps them together with.
Sure, young girls like dopey movies about gossip and boys, but they also seem to enjoy movies aimed primarily at males. What this suggests is that there is no single dimension of how girly vs. how manly a person's tastes are, at least for movies, and probably for other media -- just like there is no single sex hormone. There appear to be at least two independent dimensions (again, like there is more than one sex hormone): one preference for manly movies and another for girly movies. Young girls have higher testosterone levels than older women, which causes them to have more acne, greater lust, and a greater likelihood of committing violent crime than their elders. So that's my guess for why they like horror movies so much. But they also have higher estrogen levels than older women, making them girlier at the same time.
Despite the decline in coolness, females may become more cultured and civilized as they age, and that's just who you want to be the mother of your children. But unless you're planning on having kids right now, or are looking for a mother for the kids you already have, you want someone who is more fun and exciting, and this means much younger. If she can't have a good laugh at a side-splitting comedy or enjoy being afraid during a horror movie, she's probably past her "ideal girlfriend material" stage.
If the four female age groups were equally likely to give a movie the highest rating, and if each movie is rated independently of the others, then using a binomial test, the probability of our result is 3.2 x 10^(-11), making our result statistically significant at the 6.4 x 10^(-11) level (two-tailed). So, this is no fluke: teenage girls are far and away the group of females most likely to enjoy good horror movies.