Nov., 1921 ov. 183 
THE MIND OF THE FLOCK 
By R. C. MILLER 
HE BEHAVIOR of individuals in a group affords one of the most puzz- 
ling problems of psychology. Throughout the animal kingdom we find 
among gregarious forms a unity of purpose and a tendency to concerted 
action which does not readily yield itself to explanation. The synchronous 
flashing of fire-flies; the manner in which the gregarious larvae of certain 
saw-flies curl their tails upward by a common impulse when approached; the 
well-ordered flight of wild geese, or the intricate gyrations of a flock of Golden 
Plover, a hundred birds darting and wheeling with a grace and precision which 
no amount of training could impart; the behavior of stampeding sheep or 
cattle; the conduct of men at a political rally, or at a lynching; these are 
random examples of a unified type of action characteristic of groups. 
It is axiomatic that the mind of the group is a very different thing from 
the sum of the minds of the individuals composing it. As Le Bon (1897, p. v) 
observes of crowds, ‘‘from the mere fact of their being assembled, there result 
certain new psychological characteristics . . . (p. 6) just as in chemistry 
certain elements, when brought into contact—bases and acids, for example— 
combine to form a new body possessing properties quite different from those 
of the bodies that have served to form it’’. But this analogy, admirably as it 
states the case, hardly helps us towards an explanation of it, since the origin 
of the new properties insisted upon is quite as obscure in the one instance as 
in the other. 
The special characteristics of organized groups, according to Le Bon (loc. 
cit.), are three: suggestibility, contagion, and the possession of a sort of col- 
lective mind. As he announces shortly that contagion is an effect of suggest. 
ibility, there seems to be no good reason for considering these items separately ; 
suggestibility, furthermore, can hardly be discussed apart from its relation to 
the collective mind; the real problem of the group psychologist is, therefore, 
to find an adequate explanation of the group mind. 
It was assumed by the earlier observers, with a placid anthropomorphism, 
that the animal flock is organized somewhat on the plan of a military com- 
pany, with a regularly appointed leader who directs the movements of the 
group by means of signals or even vocal commands. Such a conception seemed 
particularly plausible in the case of the avian flock, where there is often ap- 
parent evidence of a leader and where, moreover, there is unquestionably an 
exchange of vocal signals more or less meaningful. I recall reading, on one 
of my first excursions into natural history literature, a learned account of the 
language of crows, which undertook to explain the flock behavior of these 
birds on the basis of ‘‘caws’’ of varying number and intensity uttered by the 
leader, and even ventured a tentative crow-vocabulary. Unfortunately I was 
unable to profit by this information, as the crows of my acquaintance appar- 
ently spoke a different dialect! 
. With the application of critical methods to the study of animal behavior, 
it became evident that birds are not diminutive human beings with wings and 
feathers, and the old explanation was found no longer to suffice. Thereupon 
the pendulum swung in the opposite direction, and it was insisted that the be- 
havior of the flock, with its unity of impulse and remarkable codrdination of 
