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Rh lapsed; while others, which he termed “blended,” were partly due to natural selection and partly resulted from the inheritance of acquired habit. There has been a prolonged controversy between the school of interpretation, commonly spoken of as Lamarckian, which advocates a belief in the inheritance of acquired characters, and the school, with Weismann as their leader, which questions the evidence for, or the probability of, such inheritance. The trend of modern opinion appears to be in the direction of the Weismannian interpretation. And it must be regarded as questionable, if not improbable, that instinctive modes of behaviour are in any degree directly due to the inheritance of habits intelligently acquired. That intelligent habits may secure the survival of those organisms whose germ-plasm bears the seeds of favourable congenital variations is not improbable. But in that case intelligent procedure only contributes to the survival and not to the origin of hereditary variations.

To test the hypothesis that natural selection is an essential condition to the genesis of instinctive behaviour it should be the aim of investigation to find crucial cases. This is, however, no easy task. We ought to be able to adduce cases in which, where the incidence of natural selection

is excluded, acquired habits do not become instinctive. But it is difficult to do so. It seems, however, that in young chicks drinking from still water is a habit acquired through imitation of the acts of the hen-mother. The presentation of such water to sight does not evoke the appropriate instinctive response, while the presentation of water taken into the bill does at once evoke a characteristic response. Now it would seem that in the former case, since the hen “teaches” all her chicks to peck at the water, she shields them from the incidence of natural selection. But though the hen can lead her young to peck at the water, she cannot “teach” them how to perform the complex movements of mouth, throat and head required for actual drinking. In this matter they are not shielded from the incidence of natural selection. Thus it would seem that, where natural selection is excluded, the habit has not become congenitally linked with a visual stimulus; but where natural selection is in operation, the response has been thus linked with the stimulus of water in the bill.

If this interpretation be correct we have here an example of the manner in which imitation plays an important part in the formation of habits which though oft-repeated are not transmitted as hereditary instincts. But the imitative act is itself instinctive. The characteristic

feature of the imitative act, at the instinctive level, is that the presentation to sight or hearing calls forth a mode of behaviour of like nature to, or producing like results to, that which affords the stimulus. The nature of instinctive imitation needs working out in further detail. But it is probable that what we speak of as the imitative tendency is, in any given species, the expression of a considerable number of particular responses each of which is congenitally linked with a particular presentation or stimulus. The group of instincts which we class as imitative (and they afford only the foundations on which intelligent imitation is based) are of biological value chiefly, if not solely, in those species which form larger or smaller communities.

The study of instinct is in the genetic treatment of evolutionary science a study in heredity. The favouring bionomic conditions are those of a relatively constant environment under which relatively stereotyped responses are advantageous. If the environment be complex, there is a corresponding

complexity in instinctive behaviour. But adjustment to a complex environment may be reached in two ways; by instinctive adaptation through initially stereotyped behaviour; or by plastic accommodation by acquired modifications. The tendency of the evolution of intelligence is towards the disintegration of the stereotyped modes of response and the dissolution of instinct. Natural selection which, under a uniform and constant environment, leads to the survival of relatively fixed and definite modes of response, under an environment presenting a wider range of varying possibilities leads to the survival of plastic accommodation through intelligence. This plasticity is, however, itself hereditary. All intelligent procedure implies the inherited capacity of profiting by experience. Instinctive in the popular sense, it does not fall within the narrower definition of the term; it is more conveniently described as innate. It is important to grasp clearly the distinction thus drawn. A duckling only a few hours old if placed in water swims with orderly strokes. The stimulus of water on the breast may be regarded as a sensory presentation which is followed by a definite and adaptive application of behaviour. But this specific application is dependent upon a prolonged racial preparation of the organism to respond in this particular way. Such response is instinctive. It is wholly due, as such, to racial preparation. Compare the case of a boy who learns to ride a bicycle. This is not wholly due, as such, to racial preparation, but is also partly due to individual preparation. The boy no doubt inherits a capacity for riding a bicycle, otherwise he could never do so. But he has to learn to ride none the less. Individual experience is a condition which without the innate capacity cannot take effect. Instinct involves inherited adaptation; intelligence, an inherited power, embodied in the higher nerve-centres, of accommodation to varying circumstances.

See C. Lloyd Morgan, Habit and Instinct (1896), and Animal Behaviour (1900); G. J. Romanes, Mental Evolution in Animals (1883), and Natural History of Instinct (1886); Lord Avebury, On the Instincts of Animals (1889); Marshall, Instinct and Reason (1898); Mills, Nature of Animal Intelligence (1898); St George Mivart, Nature and Thought (1882), and Origin of Human Reason (1899); E. Wasmann, Zur Entwickelung der Instincte (1897), Instinct und Intelligenz im Tierreich (1899, Eng. trans. 1903); G. and C. Peckham, Instincts and Habits of Solitary Wasps (1898); see also the bibliography (section “Instinct and Impulse”) in Baldwin’s ''Dict. of Philosophy and Psychology''.

INSTITUTE (from Lat. instituere, to establish or set up), something established, an institution, particularly any society established for an artistic, educational, scientific or social purpose. The word seems to have been first applied in English to such institutions for the advancement of science or art as were modelled on the great French society, the Institut National (see ). It is thus the name of such societies as the Royal Institute of British Architects, the Imperial Institute and the like. It is extended to similar organizations, particularly to educational, on a smaller or local scale, such as Mechanics’ or Workmen’s Institutes, and is sometimes applied to charitable foundations. In the United States the word is, in a particular sense, applied to periodic classes giving instruction in the principles of education to the teachers of elementary and district schools. The term “institute” is often used to translate the Lat. institutio, in the sense of a treatise on the elements of any subject, and particularly of law or jurisprudence; thus the compilation of the principles of Roman law, made by order of the emperor Justinian, is known as Justinian’s Institutes, and hence Coke’s treatise on English law, of which the first part is better known as Coke upon Littleton, is called The Institute. The same title is borne by Calvin’s work on the elements of the Christian doctrine. In Scots law “institute” is the person named, in a settlement or testament to whom an estate is first limited; those who follow, failing him, are termed “substitutes.”

INSTITUTIONAL CHURCH, the name generally applied both in the British Isles and in America to a type of church which supplements its ordinary work by identifying itself in various ways with the secular interests of those whom it seeks to influence. The idea of such extension of function grew out of the recognition of the fact that the normal activities of church work entirely failed to retain the interest of a large class of the population to whom the ritual formality of ordinary services was unacceptable. Various attempts were made to overcome this deficiency, e.g. by modifying the form of service or of some services, by the addition to the ordinary services of more or less informal meetings (e.g. the Pleasant Sunday Afternoon services), by specially excusing persons from wearing the normal church-going attire in holiday resorts, and by holding services out of doors. The principle underlying all these changes is systematized in the Institutional Church which, in addition to its main building for