The teaching of Charles Darwin had great influence on the con ception of the animal mind. He sought to explain the purposeful ness of instincts by natural selection. The mental faculties of man have developed out of those of animals. The desires of human beings derive from the instincts of animals. Romanes and Lloyd Morgan subscribe in a general way to the Darwinian view of the animal mind. Commencing with the 19th century the "modern animal psychology" began. According to this, many physiologists, as a reaction against the previous grossly anthro pomorphic standpoint, were led to abandon all treatment of the mental life of animals and to investigate nothing but outwardly recognizable movements and actions of animals. The young science received its first imprint from the fact, brought to light particu larly by the foremost investigators of social insects, that animals are not rigid machines but that their inborn modes of behaviour too are plastic. The fashions in which workers in different coun tries attacked the main problems were to a certain extent different from one another. In France, G. Bohn and his pupils laid stress on the faculty of associative memory as being the most important phenomenon in animal behaviour. In North America, particularly, stress was laid on the exact determination of the various aspects and phases of learning or habit formation in animals. J. B. Watson. is one of the most prominent representatives of this "behaviour ism," as the whole tendency is termed. In addition to admirable special lines of investigation in animal behaviour, H. S. Jennings, L. T. Hobhouse, Ll. Morgan, E. L. Thorndike, M. F. Washburn and others have supplied important theoretical contributions to the study of the animal mind. S. J. Holmes lays emphasis on the feelings of like and dislike as factors regulating behaviour. Dur ing the last few decades in Germany it is principally our knowl edge of the sensory faculties of numerous different animals that has been investigated, often in great detail. We will mention only the work of von Frisch on the olfactory sense, the power of dis tinguishing colours and the language of bees. To this must be added the investigation of the intelligence of apes carried out by W. Kohler, which has been so fruitful of conclusions. Here, too, numerous theoretical contributions have been published. The comprehensive work of H. Ziegler on the concept of instinct should be mentioned, as being the only comprehensive summary of the history of animal psychology.
During the last decade, however, the influence of novel trains of thought has made itself felt, taking possession of comparative psychology in a revolutionary manner. We refer to the recogni
tion of the importance, for understanding the behaviour of ani mals, of the qualities of form and totality. No longer, as hitherto, are separate and isolated stimuli regarded as the dominant factors, but it has been recognized that the separate actions of animals arise usually from the totality of the situation at the moment. Undoubtedly this mode of dealing with animal psychology is destined to produce numerous important conclusions. The most outstanding result of modern animal psychology is the proof that the first steps towards numerous phenomena of the human mind are to be found in animals. Through this, comparative psychology, which is concerned with the development of the mind in children and in primitive man, has acquired much valuable material. Just as man has long been known to be linked to the animal kingdom by his bodily origin, so now the gap is bridged which up to the present has separated him from the animals on the mental side. (See also ANIMAL BEHAVIOUR.) recent comprehensive survey of the whole subject is contained in F. Hempelmann's Tierpsychologie (Leipzig, 1926), which has a full bibliography ; other books of note include:—L. T. Hobhouse, Mind in Evolution (19oi) ; H. S. Jennings, Behaviour of the Lower Organisms (1906) ; C. Lloyd Morgan, Habit and Instinct (Leipzig, 1896), Animal Behaviour (2nd ed., 1908), Instinct and Experience (Berlin, 1912) ; G. Bohn, La Naissan-ce de l'intelligence (1909), La nouvelle psychologie animale (Iwo) ; E. Claparede, methoden der tierpsychologie Beobachtungen und Versuche (Leipzig, 1909) ; S. J. Holmes, The Evolution of Animal Intelligence (New York,, 1911) ; E. L. Thorndike, Animal Intelligence (New York, I91I) ; W. S. Hunter, The Delayed Reaction in Animals and Children (Be haviour Monographs, No. 2, 1912) ; G. Kafka, Eznfiihrung in Tierpsychologie, I. Die Sinne der Wirbellasen (Leipzig, 1914) ; psychologie (Miinchen, 1922) ; J. Loeb, Forced Movements and Tropisms (1918) ; J. B. Watson, Psychology from the Standpoint of a Behaviorist (1919) ; H. Ziegler, Der Begriff des Instinktes einst und jetzt ( Jena, 1920) ; N. Checchia, La psicologia degli animali (Turin, 1922) ; M. F. Washburn, Animal Mind (1923) ; R. M. Yerkes, Almost Human (1925) ; Marie Goldsmith, La psychologie comparee (1927) ; I. Pavlov, Conditioned Reflexes (1927). (F. HE.)