Birth Order

A nice article on birth order in the latest Time. One of the interesting things about birth order effects is that, although they are statistically subtle, people have been noticing the consistent differences between first and last borns for a long time. It's one of those examples of folk psychology where the folk turn out to be right.

It's awfully hard to resist the charms of someone who can make you laugh, and families abound with stories of last-borns who are the clowns of the brood, able to get their way simply by being funny or outrageous. Birth-order scholars often observe that some of history's great satirists--Voltaire, Jonathan Swift, Mark Twain--were among the youngest members of large families, a pattern that continues today. Faux bloviator Stephen Colbert--who yields to no one in his ability to get a laugh--often points out that he's the last of 11 children.

Such examples might be little more than anecdotal, but personality tests show that while firstborns score especially well on the dimension of temperament known as conscientiousness--a sense of general responsibility and follow-through--later-borns score higher on what's known as agreeableness, or the simple ability to get along in the world. "Kids recognize a good low-power strategy," says Sulloway. "It's the way any sensible organism sizes up the niches that are available."

Even more impressive is how early younger siblings develop what's known as the theory of mind. Very small children have a hard time distinguishing the things they know from the things they assume other people know. A toddler who watches an adult hide a toy will expect that anyone who walks into the room afterward will also know where to find it, reckoning that all knowledge is universal knowledge. It usually takes a child until age 3 to learn that that's not so. For children who have at least one elder sibling, however, the realization typically comes earlier. "When you're less powerful, it's advantageous to be able to anticipate what's going on in someone else's mind," says Sulloway.

Later-borns, however, don't try merely to please other people; they also try to provoke them. Richard Zweigenhaft, a professor of psychology at Guilford College in Greensboro, N.C., who revealed the overrepresentation of firstborns in Congress, conducted a similar study of picketers at labor demonstrations. On the occasions that the events grew unruly enough to lead to arrests, he would interview the people the police rounded up. Again and again, he found, the majority were later- or last-borns. "It was a statistically significant pattern," says Zweigenhaft. "A disproportionate number of them were choosing to be arrested."