Compare the situation today with the situation 60 years ago. Notice what is and isn't different.
All sorts of things.
Specifically, I was referring to the fact that Blacks were even poorer back than so following the argument CronoDAS's link was making we would expect there to be more unwed motherhood among them. On the other hand unwed motherhood was much more stigmatized (and no it didn't involve laws forbidding doctors from treating teen mothers).
A piece I saw that Benjamin Todd adapted from THINK's module on charity assessment. Some of you may recall the network's recent launch.
cipergoth said that it should be emphasised that this isn't a trick question where the answer is they all worked or none did.
I thought Round 2 would have no effect and expected Round #5 to have no effect not a negative one, I got 6 out of 8 correct. How well did you do?
I recommend checking out the links and references. Gwern's comment there was also interesting.