New article in Psychological Science on how to raise your kid's IQ:

The idea that music makes you smarter has received considerable attention from scholars and the media. The present report is the first to test this hypothesis directly with random assignment of a large sample of children (N=144) to two different types of music lessons (keyboard or voice) or to control groups that received drama lessons or no lessons. IQ was measured before and after the lessons. Compared with children in the control groups, children in the music groups exhibited greater increases in full-scale IQ. The effect was relatively small, but it generalized across IQ subtests, index scores, and a standardized measure of academic achievement.

I found a few things fishy with the article; number one: being oblivious to individual differences. Schellenberg is concerned so much about main (mean) effects that he totally bypasses looking at the variances. ¹ There were other things (quite major) I found wrong, but won't go into them here. ²

A lot of time and $ could be saved if Education and Psychology realized the convergence of research on raising IQ (excluding biochemical studies) --most of it in spite of the researcher(s) design/expectations/hopes--shows:

1. "IQ" and its derivatives, or, more accurately, their scores, can be raised if the treatment is intensive, continual, multisystemic (i.e., at home, school, after-school), and occurs early in the children's lives. BUT, this effect doesn't last much beyond when the treatment ends, and eventually the treatment and control groups grow rather indistinguishable. (assuming they were randomly selected) ³

2. No matter how effective the treatment is, it will not entirely get rid of individual differences. In fact, the better the intervention, the more genetic differences can express themselves, as the variance due to environmental effects will diminish.

3 (and most important): Whatever treatments are found to be effective, are not uniformly effective: There are individual differences in how people will respond to treatments. Thus, it is not enough to just look at changes in means, you have to examine the change in variances as well.

1. This is not uncommon in psychology, and represents the (unfortunate) bifurcation in science-oriented psychological inquiry that has been around since Wundt and Galton: Main Effects vs. Individual Differences.

2. I submitted a commentary to PS, so we'll see if it shows up in print before too long.

3. One of my favorite articles that showed this was:
Kreisman, M. B. (2003). Evaluating academic outcomes of Head Start: An application of general growth mixture modeling. Early Childhood Research Quarterly, 18, 238-254.
I don't have online access to this, otherwise I would provide a link. If you have university access though, I suggest reading it. It is short and, even if you don't understand the stat. methods, you can get all you need from the graphs. The article's main point: There are three types of growth trajectories: (a) "Normal", (b) Delayed, and (c) Deficit, and this was the same for both treatment (Head Start) and No treatment groups.