Phrenoblysis: Special brain and mind growth periods. I. Human brain and skull development

Although gross brain properties averaged over many individuals are highly unlikely to exhibit possible special growth periods, the hypothetical spurts in brain growth can be recovered to some extent from averaged data by computing multiyear weight increments. And, since brain weight correlates very well with skull circumference, similar spurts may be found in that parameter. A review of the literature shows that, indeed, characteristic spurts in brain and skull occur, roughly, at ages 6‐8, 10‐12, 14‐17, and possibly 2‐4 yr. The spurts are, as expected, especially clear in data from longitudinal studies, although spurts are detectable in the data from every study thus far found in the literature.