BRAIN DIMENSIONS AND INTELLIGENCE.

New Zealand Herald, Volume XLIX, Issue 15175, 14 December 1912, Page 6

BRAIN DIMENSIONS AND INTELLIGENCE.

The Australian Commonwealth Statistical (Mr. G. H. Kuibbs) has stated, m regarc to the question of brain dimensions ant intelligence, that much popular misunder standing exists in regard to what is mean when it is said that the size of the bran is possibly correlated with degree of m telligence. Mr. Knibbs mentions that Dr Raymond Pearl's investigation, published in Bionaetrika, some few years ago, let him to believe that there was no evident that brain weight is sensibly correlatec with intellectual ability. Dr. Pearl s in vestigation embraced 2100 adult male anc 1054 adult female brains, representing Swedish, Hessian, Bavarian, Bohemian and English sub-races; a.nd the limits oi the correlation were shown to range be tween . nought and -tenths, nought do noting that there is absolutely no correla tion. and unity denoting that it is com pletely established. Dr. Gladstone showec that Tn certain cases the size of the brail cannot be gauged by the size of the head His paper Jlso is published in Biometrika, In order to avoid errors arising from the very variable thickness of the skull, shot mustard seed, rape seed, and silver sane have been used to measure the internal capacity of skulls. Even if the correlator were established —that is, if, other things were established —that is,' if, other thingi being equal, size indicated intellectoa ability—we still would not be able tc decide in individual cases which brain wai the more intelligent from the skull capa city. Thuu, to take a case recently re ferred to, if there are two brains, one witt a capacity of 1471 cubic centimetres, and another 1491 cubic centimetres, it does no! follow that the latter belonged to i " slightely more intelligent person." The limitation of all correlations is that thej cannot be applied to the individual cass, They are group relationships, and axe trot only of groups.; It is only when th« groups of heads examined are bo large thai for each size there are brains of all varieties (of qualities associated with intelligence, whatever these qualities may be), that we can deduce the correlation depending on size accurately. If assured, however, that two groups of brains are fail samples, that is, have all varieties among them, then the ' correlation of brain size md intelligence, even if established, only means that the aggregate of intelligence will be found for . the group, where the brains are larger. External measurements ire very dubious, because the internal form md external are not in agreement, nor is ;he skull-thickness constant. It may be laid, concluded Mr. Knibbs, that Professor larl Pearson and Dr. Alice Lee pointed >ut as early as 1902 that "there is no narked correlation between ability and the hape.or size of the hesid," and this agrees rith conclusions of workers in Continental Europe. .. ■ ' ■ V ■ ■ '