WHERE IS THE FEMALE BRAIN ANY DIFFERENT FROM MALE?

Star (Christchurch), Issue 19109, 30 June 1930, Page 8

WHERE IS THE FEMALE BRAIN ANY DIFFERENT FROM MALE?

To-Day’s Signed Article

Specially written for the “Star” By Professor James W. Papez, Curator of the Wilder Brain Collection, Cornell University, U.S.A.

Professor Papez has examined the brains of more than forty noted men and women and it is his conclusion that there is nothing to show that the brain of a woman need be inferior to that of a man of equal rank. In the following article he discusses the whole problem and makes some interesting observations on the question of sex differences.

ONE CAN DENY that the brain taken as a whole is formed on the same general plan in the female as in the male. This follows from the facts that it is in the brain that the sense organs such as the eyes, ears, muscles and skin are most completely represented in all their varying sensory modalities. These sensory functions are properties of both sexes. In the brain these sensory experiences are constantly and completely combined into unified psychic processes which result in movement, consciousness, speech and various other functional expressions. We might expect, therefore, that the various areas of the female brain should be not much unlike those of the male. Female Brain Smaller.

It is a well-known fact that the weight and size of the female brain are generally less than that of the male. The chief reason for this is self-evident. The female in stature, size and physical development is usually the smaller and the brain generally shares in this physical proportion. The influence of the glands on the body is well known. For instance, an infant without a thyroid becomes a creature whose brain remains infantile in structure and function. The influence of the sex glands is not so striking, but that it exists is not to be seriously doubted. In spite of the fact that the brain of woman weighs less than that of man one cannot construe this difference as due to an inferior development of the brain in the female. Rather it is to be regarded as a difference linked up with the sex differentiations of the female. It has been a conclusion reached by other careful investigators that the emotional and altruistic human characteristics are best developed and represented in women and that on the other hand the male tends to develop the intellectual and egoistic characteristics along with his superior physical development. We may safely assume that the causes for these differences lie deeper than the culture of the times. They are most likely the results of the anatomy and physiology of the female which is different in many fundamental respects from that of the male. Now when we come to trace these differences to their physical basis there are several structures which may claim our attention. One of these is the brain. In the case of men and women the brain has in some respects different functions to perform due to the difference in the glandular, biological and economic functions of each sex. The anatomical structures must furnish the fundaments upon which these differences in physiological functions are based; and it is in turn these latter which furnish a basis for the psychic differences known to exist between the sexes. Brain Weight Decreases With Age. Sex differences in the brain have been sought for by many investigators. From the statistics collected by Topinard and others it appears that the average weight of the female brain is four to six ounces less than that of the male. In both sexes after the seventeenth to twenty-fifth years the relative brain weight begins to de-

crease with age. Perhaps some of this early decrease is due to the continued growth of, the other parts of the body The early anatomist, Huschke, was the first to study the brains of the two sexes for differences in structure. He made the observation that in general the parietal lobe is relatively larger in the female as compared with the frontal lobe, which tended to be larger in the male. Other men have thus been led to study the position of the central sulcus, the large cerebral furrow which separates the parietal from the frontal lobe, to determine how this varies in the two sexes. The evidence in general seemed to favour the view of Huschke, but it was found that the shape of the head also played an important part in the angular position of this furrow. Mall

could not find a significant difference between the weights of the frontal lobes of the two sexes. Winkler has found a larger motor-area and larger inferior frontal convolution in the male and a larger middle frontal convolution in the female. Where Sex Differences Most Recognised. If there is any one region of the brain in which sex differences can most often be recognised it is the upper parietal region and its medial surface called the precuneus. Here both planimetric measurements as well as the indices give greater values in the male. My measurements confirm the previous observations of Rudinger and Winkler. The differences here are often so pronounced that they can be recognised by the observer without the taking of measurements. The upper parietal lobule is the seat of sensations from the lower limbs. The most likely explanation is that the greater size of the precuneus represents the strongly developed sexual nature in man. The passion for reproduction is strongly implanted by nature in man no less than in all living animals. It is indeed essential to the perpetuation of the species. The nerve phenomena, as is well known, are most strongly developed in the male. During his whole sexual life the male is subjected to the tensions which arouse the sexual desires at the cortical level. These compel the performance of cert?in effector responses. Woman Not Inferior. The female, on the other hand, is subpected to these to lesser degree and her glandular system produces internal secretions whose influence on the brain is of a different order, as is exemplified in the maternal functions. In both sexes these differences become reflected in the functions of the brain. It is not surprising that minor differences in structure may be found to exist in the brain which are provided for the more successful performance of the ordinary functions of life. There is nothing in the outer organisation of the female brain which would make it much different or inferior to that of the male. Given the same opportunities and incentives the intellectual attainments of women need not be inferior to those of men. (Anglo-American N.S. Copyright.)