the self group. A wooden leg or a thorn in the flesh may assimilate itself closely to the self of normal experience, self being, of course, a relative or variable term the center of which alone is fixed.

Now let any circumstance deprive us, let us say, of any "a" in the series of constants and there at once arises what we may call a feeling of hiatus. If this is true of stimuli in general, it is no less true of many stimuli that are called social. The habitutal reaction to the expected resistance is a large part of our daily activity and holds the germ of social response. If the very trivial nature of the following illustrations can be forgiven they will illustrate what is meant better than psychological discussion.

The writer has two horses which for years have been driven, housed and fed together. All habitual activities have been coordinated by necessities growing out of their environment. Originally the animals (mares) regarded each other with distrust and even hostility. Even after years, their intercourse is always aggressive. One steals the other's feed and is attacked for it. There is a continual "nagging." Usually one acquires the ascendency and all that is necessary is a show of teeth on the part of one to cause flight or submission on the part of the other, which, nevertheless, is in a state of constant rebellion.

Now should one animal be left in the stable with a manger full of hay and the other driven away, the stay-at-home is restless and uneasy, declines to eat and neighs continually. The animal driven away strives to turn back, is nervous and neighs and starts out of the road on coming in view of any horse in the distance. Each, as we say, "misses" the other. What is the explanation? Evidently the simplest explanation is that a large segment has been knocked out of self. A whole group

The

of activities (resistances and the like) have been removed. equilibrium of habitual activity has been disturbed. For weeks every act has been tacitly or by unconscious implication put forth in view of a presence which could be relied upon to react in certain ways. Hitherto the horse never ate, drank or pulled

in harness without expecting a certain set of counter actions. These may have been unpleasant reactions. When she drank she expected to be shoved aside, when she pulled she expected to be tweaked by her fellow. But, whatever the character of these acts, they have ceased; to the action the wonted response is wanting.

One gets this sense of hiatus in an elementary form when, in climbing a ladder in the dark, a rung is discovered to be missing. Again, we return to the home after sending the family away on a picnic, thinking "how pleasant it will be to have a quiet day in the study" and find that the unwonted quiet sends us wandering through the empty house seeking we know not what that has gone from our life and the working equilibrium is not soon restored. This is the "feeling of hiatus." It is not confined to animate objects. The writer was once disturbed to find that he could not work well-things were not going as usual-there seemed to be a kind of mental unbalance and he discovered the cause in the fact that he had forgotten to put on collar and tie. This hiatus filled, the typewriter seemed to have as free a play of thought as ever. Certain fussy authors and artists have found it impossible to compose except in full court dress. (I fancy a disembodied spirit would have some difficulty at first with his "hiatus.")

The infant, when passed from the arms of the nurse to those of a stranger, notices the difference and shows fear or discomfort. A strange room also disturbs the equilibrium of experience. The sphere of experience created by every individual is normally a "continuum." When this continuum is disturbed the ensphering environment is left incomplete and one has the same sensation he has when the support beneath him is knocked out. It is not necessary that there should be any intellectual

status in the intercourse.

The above seems to be the most elementary condition of social existence. It consists in the enlargement of the sphere of experience by the admission of more and more elements which acquire a value to my being as a part of the equilibrium quite independent of any moral element in it. Its removal pro

duces an emotional reaction growing out of the feeling of loss -hiatus in self-solution of individual continuity. We here have the elementary mechanic of social life.

It is only after this relation is perceived as mutual that a moral element enters. When the child was about to leave home for a long visit he visited the cow, the chickens, and the cat to say farewell, and his regret in parting was greatly enhanced by the feeling of how great the grief of these fellow creatures must be in losing him. He even paid a visit to familiar spots and took leave of them with all the feeling of reciprocity that he experienced in the case of living things. These things formed a real part of his experience, he must also form a part of theirs. This feeling of participation is a second step and a moral one. This phase of social feeling is never entirely obsolete. "Who shall smoke my meerschaum pipe" and "these dear spots shall see me no more" illustrate this fact.

Add the further idea of dependence and a high social status is reached. "Really, I ought not to go away, for the servant will forget to feed the animals." Obligation has arisen because of the feeling of participation. I find that I form a necessary segment in their lives, and, as they form a part of my sphereof "me" of my larger or social self, I am obligated by that fact, i. e., by an enlargement of the law of self-preservation, to care for these animals. This is an obligation having a different kind and more intimate sort of compelling force than would be possible in the case of an inanimate and so non-participating thing. It may be that in reality the animals do not know that they are dependent on me for their sustenance, but it suffices that I imagine them so to feel. This mutuality feeling makes the obligation moral in a different sense from that growing out of fear that I might perhaps suffer a pecuniary loss by neglect. It is customary to say that the social self is ejective, i. e., that we project our own feelings and experiences into others and act in view of them. Another and in some respects a truer way of expressing it is that the self is constantly enlarging to embrace new elements. It is not simply that someone else feels as I do that might be an interesting fact, but it would have no

compelling power. It is rather that I affect the other who partakes with me in feeling. My affecting him makes him partner in my feeling. It is the element of participation or recognition of self in other which creates obligation. The mere fact that men in Mars feel as we do would not awaken moral response unless it could be showed that we affected them in some way.

Professor FISKE has indicated that the long period of helplessness on the part of the human infant is a very important factor in the intellectual superiority of the individual human being. Still more important to the race is the effect of long-continued dependence on the development of society. The tie that binds early societies is to a very large extent this same helpless period of infancy. In most lower animals this period being very short, the family relation covers a very limited period, while in the human family under ordinary circumstances this dependence is a continuing state and the family (and so eventually the tribe) becomes a permanent element to be reckoned with in all dealings with men.' It is not necessary to point out the many and far-reaching results of this fact.

Note that social insects likewise pass through a helpless stage, requiring active "nursing."

INHIBITION AND REINFORCEMENT OF REACTION

IN THE FROG RANA CLAMITANS.

By ROBERT M. YERKES.

(From the Harvard Psychological Laboratory, HUGO MÜNSTERBERG, Director.)

GENERAL PROBLEMS AND METHODS.

An investigation of the time relations of neural processes in the frog, which began with the determination of simple reaction-time (YERKES, '03, p. 598 et seq.), has now been extended to a study of the influence of complication of stimuli on time. of reaction. In this report an attempt will be made to present, in summary, certain results which contribute somewhat to our knowledge of inhibition (Hemmung) and reinforcement (Bahnung).1

Attention was called, in the paper referred to above (p. 627 et seq.), to the inhibition, by visual stimuli, of visible motor reactions to auditory stimuli, as well as to the apparent reinforcement, by an auditory stimulus (tuning-fork sound), of reactions to visual stimulation by a moving red disc. These observations led to a more detailed and systematic study of the influence of complication of stimuli, so far as reaction-time is concerned.

The work thus far done includes studies of (1) the effect of stimulation by increase in light intensity upon reaction-time to electric stimulation of the skin, (2) the effect of an auditory stimulus upon electric reaction-time, (3) the effect of visual stimulation by the appearance of a moving finger, (a) when shown almost simultaneously with the giving of the electric stimulus, and (b) when shown a considerable interval (at least

This work will be published in detail, in connection with other results, in Volume 2 of the Harvard Psychological Studies.