Study on I.Q. Prompts Debate on Family Dynamics

The new evidence that eldest children develop higher I.Q.’s than their siblings has intensified the debate over two of the most stubborn questions in social science: What are the family dynamics that enhance intelligence? And can they — and should they — be changed?

The new findings, from a landmark study published [recently], showed that eldest children had a slight but significant edge in I.Q. — an average of three points over the closest sibling. And it found that the difference was not because of biological factors but the psychological interplay of parents and children.

Predictably, the study set off a swarm of Internet commentary from parents, social scientists and others, speculating about what in families could enrich one child’s intellectual environment more than others’.

“Anyone with siblings wonders about this,” said Sue Monaco, 51, of Delaware, who has two sons and five siblings. She was one of about 150 readers who posted questions...to a New York Times Web forum about the study.

Researchers acknowledge that few of the family variables affecting intelligence are well understood, and some argue that peer influences are eventually more significant. But studies suggest that two elements are important during childhood: the perceived role a child has in the family; and the apparent benefit a child receives when he or she tutors someone else, like a younger sibling.

This from the New York Times.