The science of life : fully illustrated in tone and line and including many diagrams

HUMAN BEHAVIOUR AND THE HUMAN MIND

and limbs and squarish face. Those who suffered from dementia precox and related kinds of madness, on the other hand, were rarely of this thick-set build. They mostly oscillated between the athlete type—welldeveloped muscles with little surplus fat, broad shoulders and narrow waist, oval face and longish limbs—and the scraggy or asthenic type—thin, narrow-chested, with little muscle and less fat.

We have already found reason to suppose that the maniacs and melancholics are of Jung’s extrovert type, the dementia precox patients more introvert. So, if the correlation holds for sane people, we would expect to find the extroverts and introverts among our acquaintance differing in body as well as in their mental attitude. Popular beliefs and everyday experience justify our expectation. The fanatics, the prophets, the spinners of theories, those who will spend their life in the service of a single idea—they tend to be thin, drawn out in length—

“Yon Cassius has a lean and hungry look ; Let him be watched ; such men are dangerous.”

Calvin, Savonarola, Robespierre are examples in real life. We have no record of what John the Baptist looked like, but there is a more or less unanimous conviction that he was not short and stocky. And who could ever depict Sancho Panza as anything but plump and stocky, and Don Quixote as anything but lean ?

The medium-broad type is often the intuitively practical man, the man of affairs, the administrator: Mirabeau, Cavour, Lloyd George come to the mind. Among literary men Dr. Johnson is a good example. Fle was not interested in the working-out of philosophical systems, in close-knit imaginative constructions ; the Dictionary typifies his practical discursive bent, and Boswell’s Life is, above all, a record of his preference for the social interchange of ideas over solitary meditation. He is a complete contrast to a poet like Wordsworth, the lean lover of long, solitary walks, the constructor of elaborate systems of thought to bear the weight of his intuitive feelings about Nature.

There can be little doubt that these researches will soon link up with work upon the ductless glands. We already know that too much thyroid thins and excites, while too little bloats and damps down. The physical type produced by too much anterior pituitary resembles an exaggeration of the athletic type. Too much adrenal

Cortex masculinizes, too little pituitary fattens and makes greedy and sleepy.

On the more purely mental side people differ enormously in the way they think. Galton, in his classical book, Researches into Human Faculty, found that some people think predominantly with the aid of pictureimages ; others rely more on sound-images and, as it were, hear their thought ; still others are tied to the motor side, so that their thinking runs along the lines of an incipient pronunciation of words. Besides these, there is the abstract thinker, exemplified most clearly by the pure mathematician, who has apparently left the solid ground of sense-images and words and floats among abstractions. What is strongly developed in him is the capacity for perceiving the relations between things and ideas; he moves among problems in higher algebra as securely as the visualizer among remembered scenes. The same word is to one man a picture, to another a sound-image, to a third a cog in a logical chain; small wonder that human beings find difficulties in the way of complete mutual understanding. Recently Jaensch has brought together some interesting facts in this connection. By specially devised methods he showed that a considerable proportion of children have the image-forming capacity developed in high degree ; their mental pictures are so clear and sharp that if you tell them to project their mental image of a face, say, on a blank screen, they can, as it were, fix it there ; and you can, guided by their answers to your questions, measure it or draw it. In most cases this capacity disappears during early adolescence as the power of abstract thought is cultivated, though in some people it persists throughout life. This antagonism of picture-thinking and concept-thinking was also revealed by Galton, who found that highly educated people had, on the whole, less capacity than the uneducated for recalling vivid images.

Jaensch found further that certain drugs such as an extract of the American cactus called Mescal or Peyote (Anhalonium) could increase the vividness of image-formation. It conferred vivid imagery upon many of those who normally lacked it; while in those in whom the faculty was already strong the pictures were converted into hallucinations: the image was projected into the external world and seemed to exist in its own right. Certain preparations of calcium, on the other hand, often reduced

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