Evening Star Newspaper, December 7, 1930, Page 88

T3 THE SUNDAY STAR, WASHINGTON, P. €, DECEMBER ¥, 19%. How the BRAINS of TWINS Differ - Science’s Newest Studies of “Identical” Chil- dren Reveal Them as Being Amazingly Dissimilar in Mental Traits, Although Physically Alike as the Twvo Peas in a Pod. BY MARJORIE VAN DE WATER. alike as two peas in a pod! This ex- / pression is immediately brought to / mind by the sight of what scientists 3 term “identical twins.” Wt And recent studies of identical twins by physiologists, psychologists, fingerprint ex- perts and students of heredity have revealed that the old saying really understates the case. Identical twins are mere alike than two peas in a pod! The two peas when they grow up into adult vines lose their similar appearance. One vine may be tall and the other short; one thriving and the other puny. The human identical twins continue to resemble each other closely all through life, and "often die of the same diseases. Even in the few known cases where the twins have been separated very early in life and brought up under very different conditions, they continue to look so much alike that even their intimates require the traditional pink and blue ribbons to tell them apart. BUT how about the minds that dwell within the duplicate bodies? Are they identical also? Psychologists are eagerly seeking the answer to these questions, and are searching out pairs of twins the world over for detailed study. Dr. Albert F. Blakeslee of the Department of Genetics of the Carnegie Institution of Wash- ington has recommended the starting of a special school in New York City at which the only pupils would be identical twins. The teachers would also be identical twins, There educators could try out the new methods they devise. If one twin under the new method showed great improvement, while the other one of the pair, under the old method, failed to improve likewise, the experimenter could feel that the new method was better, In this school also the psychologist could give the mental tests designed to measure the native ability of the children and find out to what extent the twin children will give twin answers. The comparatively few pairs § one case did they receive marks that not exactly uniform. In that case the of one boy was called “excellent,” while was marked “very good indeed.” received the same number of points trance examination to the medical s ye) gisfg = Cwywmammmum acquaintance not twins who could Washington, D. C,, gives you the answer. She has given mental tests to twin children under eircumstances making it impossible for them to get together about them at all. Yet they gave answers that were almost identical and Teceived very nearly the same total scores in the grading. In the case of adult twins, especially those who have been brought up by foster parents in sntirely different surroundings, it has been found These children are twin {ct could any 1wo 4-year-olds be less alike? freternal, or sweo brothers. that the two will respond a little differently to the mental examination. But the differences have never been so marked as the likenesses. Although twins have only recently claimed the attention of science, they have always been interesting to people in general and have been a favorite theme of the fiction writer. Some ancient tribes. and indeed a few parents in America, regard twins as a special curse, and would like to know how to avoid this doubling up in the nursery. Others consider them a special mark of distinction. And this excitement is not because twins are S0 very rare. In this country about 1 per cent of the births are twin births, but in many parts of Europe the rate is higher. In Heidel- berg one birth out of 52 brings twins. Rather it is the mystery of just what produces twins and why they seem to be cut from exactly the same pattern in a world where there are certainly an infinite variety of molds that piques the curiosity. No one can tell with certainty what causes multiple births. Some tendency toward “twin- ning” does seem to run in certain families more than in the average group. TWINS and triplets usually appear in a family which has already known multiple births either on the mother’s or the father’s side. And one palr of parents will often have more than They are thbmuthemfimbmmhawisedmply Twins who have traveled parallel roads all their lives. Left, Gilbert Grosvenor, editor of the National Geographic Mag-. azine, and his twin brother, Edwin, law- yer and writer. one set of twins. A record seems to have been made by a couple recently reported in Mexico as having in the course of 40 years of married life no less than 18 pairs of twins. About the manner in which twins are formed biologists have learned a great deal in recent years. Through the stidy in the laboratories of rats, armadillos and starfish by means of microphotographs of the eggs of these animals scientists have pieced together the amazing story of how two human beings can be formed from the single egg cell that ordinarily de- velops into one person. All ltving creatures from the humblest form of jellyfish to the wisest college professor have thenmebecinnlngulfinydnflemeen or ovum. But the egg cell very soon divides into two and then those two split into four and this process continues until long after the birth of an infant there have been developed all the Biologists therefore say that every normal individual is a perfectly balanced and combined pair of twins, ONcl in a great while because of something which disturbs the normal course of de- velopment the cell may separate into twe entirely distinct parts, each of which develops into a complete and perfectly balanced human being. These two individuals coming from s single ovum are what biologists call identical twins. It has been found that the right hand of one of these persons is more like the corre= sponding hand of his twin than it is like his own left hand. He is more like his twin than he is like himself! Not all twins are identical twins, however. Some are merely ordinary brothers and sisters who happen to be born at the same time. Biologists have found that such non-identical twins, or fraternal twins as they are sometimes ulled,donoteomexromthenmem“ln. but from two eggs which happen to become fertilized at or near the same time, resulting in two simultaneous births, Fraternal twins may not even be of the same sex and are no more like each other than they are like other brothers or sisters at the same age. Indeed, they may be striking contrasts— one blond and the other brunette, one growing slowly and the other rapidly, one bright and the other slow to learn. y HE only striking difference that sometimes appears In the physical make-up of identical twins is what scientists appropriately call mirror imagery. The one twin instead of looking exe actly like the other will see his twin as he would see himself in the mirror. That is, his right side is like his twin’s left side. Everything is reversed in the other twin. A right-handed twin will have a left-handed mate. The hair of one will part naturally on one side, while the other must comb his in the opposite direoce tion. This duplication in reverse can be noticed in even such minute detalls as the way the lips curve in a smile, and it accounts sometimes for & very different expression on otherwise idemtie cal faces. Even the lines in the palm of the hand core respond very closely for identical twins, although they may correspond either exactly right hand for right hand, or in the case of the mirror type of twins, right hand for left. - PFinger prints, which have long served as means of distinguishing one man from all his fellows, cannot be infallibly used to tell ome twin from another. In most instances there are slight differences, but sometimes even the expert cannot tell which twin made a particular print. Handwriting, however, which has been thoughs by some people to betray the individual’s secret thoughts and character, is not the same., In fact, it is not more like than the handwriting of other brothers or other pupils learning thefe penmanship from the same teacher. Penmsne ship, it would seem, depends more upon traine ing than personality after all. PBOP. JOHANNES LANGE of the 00!'_ Institute for Psychiatric Research im Munich has studied 30 pairs of twins having ene Continued on Fijteenth Page