Here's one anecdote. Preceding it, the authors describe how violent crime was climbing at a rapid rate up to the mid-nineties, and then it dropped off unexpectedly but universally. They summarize some of the most popular ideas of why this happened ("These stories were not only logical; they were also encouraging, for they attributed the crime drop to specific and recent human initiatives"), and then assert that they weren't true. Then they say the crime drop started 20 years earlier, and give a quick summary of how abortion became legal.
So how did Roe v. Wade help trigger, a generation later, the greatest crime drop in recorded history?
As far as crime is concerned, it turns out that not all children are born equal. Not even close. Decades of studies have shown that a child born into an adverse family environment is far more likely than other children to become a criminal. And the millions of women most likely to have an abortion in the wake of Roe v. Wade - poor, unmarried, and teenage mothers for whom illegal abortions had been too expensive or too hard to get - were often models of adversity. They were the very women whose children, if born, would have been much more likely than average to become criminals. But because of Roe v. Wade, these children weren't being born. This powerful cause would have a drastic, distant effect: years later, just as these unborn children would have entered their criminal primes, the rate of crime began to plummet.
It wasn't gun control or a strong economy or new police strategies that finally blunted the American crime wave. It was, among other factors, the reality that the pool of potential criminals had dramatically shrunk.
So I've heard these arguments before in different forms, and I certainly agree that planned families and wanted children - of which abortion is an unfortunate but sometimes necessary part - make a huge difference in what kids do when they grow up. But I have to take on faith the authors' assertion that this cause-and-effect really exists, and that the other factors didn't have effects. I'm sure they have more data on which they based their assertions, but I want to see it and see if I reach the same conclusions.
Another reason that I'm skeptical is that even in the introduction, the authors play psychological games with statistics:
In a typical election period that includes campaigns for the presidency, the Senate, and the House of Representatives, about $1 billion is spent per year - which sounds like a lot of money, unless you care to measure it against something seemingly less important than democratic elections. It is the same amount, for instance, that Americans spend every year on chewing gum.
The comparison between campaign spending and chewing gum is supposed to make me see that campaign spending isn't so bad after all, except that the former is what an individual spends and the latter is what a large aggregate spends, and comparing them is misleading. And the use of chewing gum as the example just tries to trivialize it more.
Anyway, in the talk, the two authors introduced themselves and how they (an economist and a writer) came to work together, and then talked about a couple of anecdotes that weren't in the book. One was about a Yale economist, Keith Chen, teaching Capuchin monkeys how to use money. Over 6 months, they taught the monkeys to first associate and then trade washers for high-sugar foods that they loved, and found that they reacted rationally to price fluctuations (e.g. they bought less of their favorite food if it cost more) and irrationally to a game where they could lose their money, "just like the average day trader." They also related that researchers observed monkeys steal money from them, and claimed that monkey prostitution was observed as well. (Another of those "really?" moments there.)
In response to one question, the authors argued that the usual metrics by which schools are measuerd - class sizes, test scores, the number of students to go on to college or get good jobs, etc. - don't matter, and that the important parts are the quality of teachers and their peers. They quoted studies done on the Chicago public school lottery system, where students who won the lottery to get into a good school didn't perform better - indeed, they did slightly worse - than similar students who didn't win the lottery and had to go to a "worse" school. However, the students at the worse schools did get into trouble more.