Sep 27, 2009

Opportunity costs of romantic evenings and IQ of babies

Couple of months ago we were talking with my girlfriend about the impact of season of your birth on your intelligence, and health. My theory was that less educated, poor people are more likely to conceive a child in the winter. Children born in fall and early winter underperform their peers simply because they are more likely to come from a family with low socioeconomic status.

Guess what, NBER published a paper "SEASON OF BIRTH AND LATER OUTCOMES: OLD QUESTIONS, NEW ANSWERS, 2008" that is supporting my theory. The sad thing is, that I am not the author of the paper, the cool thing is that they got it wrong (or so I believe)! They argue that less educated, poor man are more likely to be exposed to temperature extremes. Such exposure lowers their sperm count and they are less likely to conceive a child. Fine, but I think I have a more plausible explanation.

In my opinion the differences are caused by opportunity costs of making a baby. The less intelligent baby is likely to be conceived in december, january, february , and march. All of these are rather cold months.
In my opinion richer people have significantly wider choices of entertainment during the winter, but the gap narrows during the summer. In the summer you can hike, go to a park, sun bath, swim in the lake, jogg all of these without having to pay a single penny. What can you do for free in the winter? Virtually nothing! While the rich ones have wide range of possible pastimes in the winter (skiing, snowboarding, going to movies, going for a dinner and thousands more) and would have to give them in order to have a romantic evening, the poorer ones have way simpler choice: "Shall we watch TV or make love?". And this is what in my opinion drives the difference, opportunity costs of romantic evenings! On average smartest children are conceived in the months when the gap between opportunity costs of making a baby for a rich and poor are smallest. The least intelligent are conceived when the gap between the opportunity costs is the largest...

7 comments:

Cam said...
This comment has been removed by the author.
TomasHozik said...

Why was the comment removed? I wanna some critique on my controversial theory!

Pierre-Louis said...

here are a few things I want to know:

- does season of birth have an impact on babies of well off people?

this would suggest the season effect is not only driven the parent's income.

- in other words, are season of birth and parents income significant when in the same regression explaing child IQ?

- I want to see the scatter plots of number of babies against month of the year for rich and poor people...

- what are we interested in, the impact of season of birth, or the persistence of poverty and low IQ?

If the latter is the case, season of birth should be a valid IV for parent's income...despite the discussion in the NBER paper that misses the point.

But I think season of birth might affect IQ despite the parents income. It changes the age at which you enter school, and for hockey players it has a huge impact.

and for soccer players?.

How about your star sign???

TomasHozik said...

Upff, I didn't mean it that seriously. :-) It was just a theoretical idea. I don't have the data (I am not sure whether it exists). If I were to test it seriously, then I would go through the steps PL proposed...

There is a lot of papers explaining the effect, but I don't think anyone has argued (and tested) along the lines I've proposed. The NBER paper is relatively close...

Pierre-Louis said...

yeah i tend to take things seriously...;) except my own papers!

Lala said...

Interesting, but I disagree with the opportunity cost explanation of autumn/winter babies' lower IQ, what if we look at sex not as the opportunity cost of romantic evening but rather as a complementary good to good time?

and from a more prosaic side, the paper does take into account N-S hemisphere season differences, right?

TomasHozik said...

Complement - Hmmmm... That's a good point.

I don't know, I guess you're right, this effect is gonna go in opposite direction than what I've proposed...

thx.
still think it would be fun to test it...