Brain size and intelligence: erratum, addendum, and correction

The current paper corrects some previously published results (Egan, Chiswick, Santosh, Naidu, Rimmington & Best, Personality and Individual Differences, 17, 357–367, 1994), and suggests that the range-corrected correlation between total brain volume and Full-Scale IQ, controlling for height and weight, is 0.48. not 0.66. This result replicates correlations of similar sizes found by researchers from four different research teams. The high correlation between CSF volume and IQ measures in this study is discussed in reference to the method of estimating CSF volume. It is suggested that an automated method may have provided an indirect measure of brain surface area. Finally, by simulating the range of possible partial correlations between brain volume and intelligence controlling for height and weight, it is argued that the correlation between brain volume and measures of IQ is only modestly affected by correction for body size. As such, brain volume/IQ coefficients should only be corrected for body size if data from the specific study warrants such a procedure.