OLDER & SMARTER

Here are the results of a couple of papers that were recently published in the high profile journal Science. Basically it is telling me what all of us elder siblings have always known- we are smarter than our younger siblings.... take that Andy!

For more than a half century, researchers have debated the effects of birth order on intellectual performance. Although numerous studies have noted a negative association between the two, critics have argued the results citing uncontrolled differences in factors such as family size, parental IQ, and socioeconomic status. In a new study in the 22 Jun 2007 Science, Kristensen and Bjerkedal reported results from a study of nearly 250,000 Norwegian 18- and 19-year-olds showing that older siblings had higher intelligence quotient (IQ) scores than younger siblings. To test whether the difference could be due to biological factors, as some have proposed, the researchers looked at the scores of young men who became the eldest in the household after an older sibling(s) had died. Their scores, it turns out, were similar on average to those of biological firstborns. These results suggest that the relation between birth order and IQ is dependent on social rank in the family as opposed to true biological rank. An accompanying Perspective by F. J. Sulloway discussed some of the competing theories about birth order and intelligence and their ability to account for the tendency of younger siblings to score higher IQ scores than older siblings when tests are given under the age of about 12.