Figure 1.

Results of the clustering procedure. Average values of Intelligence scores and brain morphometry for the three IQ groups resulting from the two‐step clustering procedure (Akaike's Information Criterion, log‐likelihood). The results confirmed a good separation between High‐IQ, Average‐IQ, and Low‐IQ subjects for the main IQ scores (FSIQ, PIQ, VIQ) and subtests, whereas no significant difference emerged for total brain, gray matter, white matter, and CSF volumes. White boxes represent the 3th quintile (central line) as well the 2th and 4th ones (left and right edges) of the overall sample distribution. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]