BRAIN WEIGHT AND INTELLIGENCE.

New Zealand Mail, Issue 1737, 14 June 1905, Page 17

BRAIN WEIGHT AND INTELLIGENCE.

Is it a good thing to have a large head? Does a large brain mean a large mind ? asked Professor Karl Peart son, in a recent lecture at the Royal Institution on this subject. He concludes:—Yve are met with the initial difficulty that not even do brain weight and skull capacity accurately correspond. Even when a careful series of measurements has enabled us to gaug% with great precision the roominess of a given head, we are able only to form very rough estimates of the weight of the contained brain. But we will let that pass, and observe the facts as to brain weight itself.

So far is brain weight from varying directly with intelligence that it actually varies—the intelligence being neglected—with such things as stature and; a so. The weight of our brains declines from about the period of puberty onwards ! "Whereas our stature only begins to clecl ne- after 28 or so. Plainly knowledge cannot be measured in scales like cheese or brain matter.

Tlie-n, again, brain weight varies w r ith stature and with body weight. The taller you are and the heavier you are, the bigger, on the average, will be your brain. Yet giants are usually conspicuous for their feeble intell gence.

But now iet us turn to the most interesting point of all. Ignoring all other factors, what can be said as to the relation between bran weight and intelligence? The quest iojg is not so easy t-o answer, especially as regards adults; for who will agree as to the criteria of intelligence? Knowledge and attainments can readily be tested ; not so natural faculty or intelligence. Professor Pearson has had to give the question up as regards adults, save for on© inquiry into the brain weights—corrected for age, stature, and body weight—-of a series of Cambridge graduates. He found certain small differences between the brain weights of ordinary passmen and of honour graduates ; but the results are very inconclusive.

It is possible, however, to measure Avith some degree of accuracy the intelligence of children, and circulars designed for this purpose were sent to school masters, and have yielded statistics which deal with some 6000 children. The result of this inquiry is to show that if there is any real relation between brain weight and intelligence, it is too slight to be detected. * This conclusion has been compared with results obtained by estimating the brain weight of various distinguished men, such as Jeremy Bentham, the great exponent of utilitarianism, who left hi* body to University College. It appears that Bentham, the wisdom and foresight of whose views have been attested by the trend of legislation ever since biw death, was physically mediocre in every respect. Similarly the skull which is almost certainly that of Dante has been, studied, and yields the conclusion that f be brain weight of the author of the “Di vina Oommedia” was about 100 grammes less than that of the average Englishman! Professor Pearson’s own brain weight is inappreciably above the average. We may therefore sum up the result of this prolonged inquiry as a “complete failure at present to discover any substantial relation between skull capacity, or size of head, and intelligence, ’wovided we confine our attention to the same class, i.e., individuals of like nurture and education, within the same racial component of our mixed' population.” To guess at a man’s probable intelligence there is one way in which you may succeed. That is not by estimating his brain -weight, but by studying the -ecords of his parents and grandr*nvents. It is not quantitv but ounl'ty of brain that tells, and quality of brain is a matter of inheritance.