Haven't seen the SciAm article yet, but your post reminds me of a discussion I had on sci.psychology some years ago about the "Flynn effect". This refers to a trend of increasing IQ scores, including SAT scores, over the years that requires such tests to be continually renormed:

From: "Robert Clark" <rcl...@op.net>
Date: 1997/09/21
Subject: The Future of Human Intelligence. Large Bulbous Heads?
Newsgroups: alt.psychology, rec.arts.sf.misc, rec.arts.sf.science, sci.anthropology, sci.archaeology, sci.bio.misc, sci.cognitive, sci.psychology.misc, sci.psychology.theory
http://groups.google.com/group/sci.psychology.misc/browse_frm/thread/4b417f3234efc9cf/b6d9e963a671dda3

This refers to an article in the American Scientist on the "effect". The url for the article is different than as cited in the post. You can now find it here:

FEATURE ARTICLE
Rising Scores on Intelligence Tests.
Test scores are certainly going up all over the world, but whether intelligence itself has risen remains controversial.
Ulric Neisser
This article originally appeared in the September-October 1997 issue of American Scientist.
http://www.americanscientist.org/issues/feature/rising-scores-on-intelligence-tests/1

When I first wrote that post, I meant the title rather humorously but I was startled to find in reading the American Scientist article more closely that there actually has been a general trend to larger head sizes. This is mentioned in the section on Nutrition on page 6 of the article. The article attributes this to the fact that heights in general are increasing. But I wondered in a following post to that thread if also newborn head sizes were also increasing.

Bob Clark