CATIONAL PSYCHOLOGY) .
embraces the problem of so fitting the worker to his work that the maximum of production shall be obtained with the least expenditure of energy. This branch of applied psychology has been influenced to a great degree by the efficiency engineers, and it is they who have set many of the problems which have engaged the interests of the psychologist. Foremost among these problems are the economies to be gained by the analysis of work by means of time and motion studies. They reveal waste of motion through the improper placing of materials, improperly directed movements and the uneconomical routing of work generally. Laboratory and field studies have shown the economies of properly • distributed work and rest schedules, and of the control of such environmental conditions as ventilation, illumination and distracting noises. The results of attention to such matters, when measured in terms of output of work, have shown surprisingly large percentages of increase. These changes have been found in most cases to produce their effects gradually a period of six months being required in certain instances to attain the total benefit from a change of work schedule. Not all the changes introduced into working conditions by the efficiency engineer are justified on psychological grounds.
Too high a degree of specialization and standardization of func tion may lead to a monotonous routine that requires some cor rective in the best interests of the worker. From the standpoint of the applied psychologist, more attention should be paid to the satisfaction to which the worker is entitled than is generally paid to that important matter (see INDUSTRIAL PSYCHOLOGY).
This branch of applied psychology should include all problems concerned with the distribution of goods. After deducting, however, all questions of selection of employes, and all questions of production, there remains primarily the task of acquainting the public with the goods that are avail able for distribution, namely, advertising and selling. Of these, advertising has received by far the major interest. This is pri marily due to the fact that good advertising lends itself readily to study and analysis, both in the field and in the laboratory, while good selling remains a more intangible quality. The greatest contribution of psychology to advertising is to be found in the motivation of behaviour,—the fact that behaviour is determined by a series of causes, some of which are within the control of the advertiser. Thus, the desire for self-assertion, for protection, for comfort, etc., are played upon effectively in the sale of a great variety of commodities. All the facts of attention, per ception, memory, feeling, belief and suggestion which have been accumulated over years of laboratory work are applicable directly to the problem of getting the attention of the reader, making a permanent impression upon him, and leading him to a favourable reaction toward a given product. Field studies of the reactions of people to such mediums as the Saturday Evening Post have re vealed much valuable information concerning the manner in which the attitude of the reader may be affected by the use of colour, of large space, of unique illustrations, of so-called pre ferred positions on the page and in the medium itself. All the psychological principles which have been applied to advertising are equally applicable to the problems of selling, except that greater flexibility is possible because of the direct contact between salesman and customer (see PSYCHOLOGY OF ADVERTISING).
Modern psychology, as the study of human behaviour, has many points of contact with the law, al though relatively few of them have been developed. As far as prevention of crime is concerned, psychological analysis has thrown much light upon its determinants. Discarding the notion of responsibility as it is usually conceived, it has sought causes and contributing factors. Contrary to common opinion, such hereditary factors as defective intelligence are found to play a minor role, while social inheritance and environmental factors play a major part. Even among the environmental forces, poverty is of slight influence compared with defective discipline in the home. A psychological analysis of preventive measures at present in force shows their weaknesses and suggests methods for their improvement. The establishment of psychological clinics in con nection with the courts and within the larger prisons furnishes the means of analysing causes of crime, and of determining a prison regime in accordance with the needs of the individual prisoner.
The most interesting applications of psychology to the law are to be found in the field of evidence. The great work of Wigmore (Principles of Judicial Proof, 1913) has shown the need of a sound conception of psychology in the interpretation of evidence. Every bit of evidence is definitely limited in its range and validity by the sensory capacity, the perceptual power, the ability to judge and remember on the part of the observer. Since these functions vary greatly from individual to individual, it follows that evidence must be evaluated upon a knowledge of the limi tations of the individual who is giving it.
The use of various devices for detecting guilt or deception de pends upon the influence of the consciousness of deception upon such psychological processes as blood pressure, breathing, psy chogalvanic reaction and the speed of articulation. In laboratory tests of such methods a surprising degree of accuracy in the detection of deception is attained. The principles underlying these procedures have not yet attained sufficient scientific support to justify their use in the courts for the determination of guilt.
Psychology and medicine have been closely associated for more than 5o years, and important con tributions have been made in the field of mental diseases by both physicians and psychologists. In spite of this, there has grown up no body of information definitely labelled as medical psychology, nor a group of specialists similar to those in the fields of industrial and vocational psychology. There are the psychiatrists and psychopathologists, who are interested in mental and nervous diseases from the medical rather than from the psychological point of view, and there are the specialists in abnormal psy chology, who are usually psychologists. There is no provision in most medical schools for training in general psychology which would create the psychological point of view, and bring the physician and psychologist into closer contact.
The elaborate system of psychoanalysis for the diagnosis and treatment of patients grew up without adequate contact with normal psychology, and many conflicts and misunderstandings have resulted therefrom. Numerous important contributions to theory and practice in relation to mental disease have been made by psychologists from time to time, while hospitals and research institutions are coming to recognize the significance of psychologi cal tests, and in some cases have appointed psychologists upon their staffs.
A number of organiza tions have been established for the promotion of applied psy chology, and for establishing contact between the psychologist and the problems of business and industry. Best known among these are the National Institute of Industrial Psychology (Lon don), the Psychological Corporation and the Personnel Research Federation (New York city). The International Conference of Psychotechnics is a permanent organization which meets annually in different countries. As the name implies, it is truly inter national in scope, with German, French and English as the recog nized languages for communication. In many countries there are institutions for promoting some special phase of applied psy chology, as vocational guidance.
T. Poffenberger, Applied Psychology; Its PrinBibliography.-A. T. Poffenberger, Applied Psychology; Its Prin- ciples and Methods (1927) ; G. M. Whipple, Manual of Mental and Physical Tests (1921) . For a presentation of the elements of statistical methods of treating biological data, see H. E. Garrett, Statistics in Psychology and Education (1926) ; T. L. Kelley, Statistical Methods (1923) . E. L. Thorndike, Educational Psychology (1914) ; D. Starch, Educational Psychology (1927). On vocational psychology see R. Pintner, Intelligence Testing (1923) ; E. K. Strong, "An Interest Test for Personnel Managers," Journal of Personnel Research, vol. v., PP.
(5926) ; H. E. Burtt, Employment Psychology (1926) ; C. H. Griffiths, Fundamentals of Vocational Psychology (1924) ; W. V. Bingham and M. Freyd, Procedure ih Employment Psychology (1926) . On industrial psychology see L. M. Gilbreth, The Psychology of Management (1914) and Applied Motion Study (1919) ; H. M. Vernon, Industrial Fatigue and Efficiency (1921) ; Reports of the Industrial Fatigue Research Board of London ; H. C. Hink, Employ ment Psychology (1919) ; A. T. Poffenberger, Psychology of Advertis ing (1925) ; E. K. Strong, The Psychology of Selling and Advertising (1925). For books on legal psychology see S. S. Glueck, Mental Disorder and the Criminal Law (1925) ; C. Murchison, Criminal Intelligence (1926) ; W. M. Marston, "Psychological Possibilities in the Deception Tests," Journal of Criminal Law and Criminology, vol. xi., pp. 551 ff . (1921) . For medical psychology see J. J. B. Morgan, The Psychology of Abnormal People (1928) ; E. S. Conklin, Principles of Abnormal Psychology (1927) ; R. S. Woodworth, "Some Criticisms of the Freudian Psychology," Journal of Abnormal Psy chclogy, vol. xii., pp. 174 ff. (1917) ; G. H. Kent and A. J. Rosanoff, "A Study of Association in Insanity," American Journal of Insanity, vol. lxvii. (1919) ; S. I. Franz, Handbook of Mental Examinations (1919) . See also H. D. Kitson, "Vocational Guidance in Europe," School and Society, vol. xvi., p. 645 ff. (1922). (A. T. P.)
