AESTHETICS, EXPERIMENTAL. Great artists through out the centuries have contributed to an empirical aesthetic in the broad sense of the term. Some of them have given us exten sive treatises based upon an analysis of their own methods of artistic production, or upon an investigation of existing works of art. Hogarth, for example, examined many forms of architecture, as well as the lines of the human figure, in a search for a norm of beauty which he thought eventually he had found in the ser pentine line, and Goethe in his Farbenlehre has made keen obser vations in regard to the aesthetics of colour. From the long list of names might also be mentioned Leonardo da Vinci, Sir Joshua Reynolds and M. E. Chevreul. G. Th. Fechner, however, is generally considered the founder of experimental aesthetics. He not only discussed the formal, or direct, and the associative fac tors underlying beauty on the basis of his experience of works of art, but he devised experiments in order to settle scientifically the question of the most pleasing proportions in geometrical forms and in line division. This problem had engaged the attention number of writers, whose results are in strong disagreement. Wolff insisted upon the proportion of I :I, while Adolf Zeising thought the proportion of the golden section (i :1.618) to be the most pleasing, on the principle that it gives the greatest possible diversity in a harmonious unity. It was the proportion of the golden section that Fechner desired to put to experimental proof. He spread figures of different sizes, such as ellipses, before the observer, with instructions to choose the one which seemed the most pleasing, or he had the person construct a figure according to the most pleasing proportion. It was these two methods of choice and construction, together with that of use, which he pro posed as the proper empirical methods of investigation, and these methods have continued to be employed up to the present day. Fechner found the golden section to hold in many instances, but he also found the proportions of r :1 and r :3 to be pleasing under certain circumstances. Lightner Witmer thought that Fechner used too few figures, and that the experiments were not properly controlled. He therefore used a serial order of figures with the least perceptible difference of proportion between them. He also had the figures compared in pairs. His results do not always agree with those of Fechner, but he established the importance of the golden section for rectangles and ellipses and line division. An interesting fact came to light in experiments conducted by R. P. Angier. His subjects divided a line at what seemed to them the most pleasing point. Although several persons came near the golden section, no one actually chose it. Nevertheless, the average of all observers was almost exactly the golden section. His results served as a warning not to place too much weight upon averages in the search for an aesthetic norm. In general, however, it may be said that the golden section and symmetry are pleasing, that a division very near the middle and one which makes the shorter line less than a quarter of the length of the whole line are displeasing.
Numerous experiments have been made upon form and balance, with the principal aim of obtaining a psychological explanation of the pleasing effects. T. H. Haines and A. E. Davies, from their work with a series of cards having a constant length and varying width, decided that eye-movements, associations, balance between forces of attention, and suggestion, were the factors which deter mined the aesthetic effect. Ethel D. Puffer made an extensive study of balance by the use, among other objects, of lines of various sizes and in various positions. She found that the best aesthetic balance generally corresponded to the mechanical bal ance, and explained the results in terms of interest which, in the last analysis, meant for her a balance of motor impulses. L. J. Martin asserted that our preference for lines and shapes depends very much upon our attitude toward the objects we are judging. A slanting line, when interpreted as a bad vertical, is displeasing, but when we think of it as a horizontal line which is raising itself to a vertical, it is pleasing. F. Sander believes that absence of feelings of tension produces a restful effect such as is experienced in viewing Greek architecture, while vivid tensions underlie our reactions to Romanesque and Gothic architecture. Th. Lipps's theory of empathy has also frequently been offered as an explana tion of aesthetic pleasure in form. It has further been shown that straight, curved or zigzag lines not only give us varying degrees of pleasure, but arouse in us distinct moods.
William Preyer made one of the first investigations of the col our sense of infants. He found yellow to be preferred to blue. William McDougall found that in the fifth month the child's order of preference was red, green, blue. C. S. Myers found that red and green were distinctly preferred to the other colours and to greys. The child examined by C. W. Valentine preferred yellow, then white and pink and then red. T. R. Garth made an investi gation of i,000 white children, and found the order of prefer ence to be blue, green, red, violet, orange, yellow, white. In the investigation of full-blooded Indians, he found the order to be red, blue, violet, green, orange, yellow, white.
Sound.—The most important work on the psychology of music is that of Carl Stumpf. His book Tonpsychologie (189o) is a classic in this field and contains, among many theories and facts of importance, his psychological theory of consonance, which is based upon an empirical study of the perception of tonal com binations. For Stumpf, degree of consonance is correlated with degree of fusion of the two tones of a musical interval. In his subsequent writings, he has vigorously attacked the physical theory of consonance of Herman v. Helmholtz and F. E. Kruger. Stumpf has also done extensive work upon the tonal quality of vowels and consonants. One of his latest investigations in the auditory field is a comparison of singing and talking, which he finds not funda mentally different. In speaking we use for the most part a con tinuous change in tone, while in singing we use discrete tonal steps. H. T. Moore has shown experimentally that, up to a cer tain point, the pleasantness of tonal intervals grows with our experience of them, which accounts for the gradual change in our attitude toward consonance and dissonance. 0. Abraham and E. M. von Hornbostel, in their analysis of tonal intervals, have discovered two factors underlying the experience, one a qual itative, the other a quantitative, which they call distance or width of interval, and accord quality, respectively. C. E. Sea shore has devised a series of tests which can be given by means of phonograph records. In his latest work he describes the results obtained by photographing the vibrations of the singing voice. He has detected the presence of the vibrato, or synchronous oscilla tions of pitch and intensity at the rate of five to eight per second in artistic singing.
\ In experiments upon the appreciation of pictures the intro spective method has usually been employed. 0.1pe showed pictures for three seconds each to a number of persons, and re corded their reports. He did not find evidence of empathy to support Lipps's theory. On the other hand, muscular sensations in a form which, according to Karl Groos, is called inner mimic ry are present at times, but not always. A unique method of in vestigating the effect of pictures upon children was used by R. Schultze, who photographed the children while they were looking at the pictures. One was often able to judge from the photo graphs which picture the child had been looking at, as well as the mood which had been aroused.
A laboratory research in the field of literature which is sugges tive, both from the point of view of method and content, is that of R. C. Givler. He showed conclusively the importance of the mere sound of words in conveying the meaning as well as the moods of poetry. Most of the investigations of the aesthetics and psychology of prose and poetry, however, have been in the nature of a direct analysis of the works themselves, or a study of the life of the artist, and do not come under experimental aes thetics in the narrow sense of that term, as used in this article. J. L. Lowes' The Road to Xanadu (1927) might, however, be mentioned as a model piece of research of this nature. Comparing the contents of a note-book left by Coleridge with the text of The Rhyme of the Ancient Mariner and Kubla Khan, Lowes has been able to analyze most convincingly the subconscious mind of that poet. Freud and his followers have also made numerous analyses of the subconscious minds of artists. Their results will undoubt edly be of interest to those persons who believe in the psycho analytic method, and even the sceptic will find some suggestive material in their writings.