I
Boundary phenomena, according to the writer's terminology, are the events arising out of the boundary between neighbouring regions in the life space, and social boundary-phenomena are those occurring between regions differentiated by social non-homogeneity.
Everyone in Formosa, belonging either to the ruling group or to the ruled groups racially different, has these two kinds of group psychologically as neigh-bouring regions in his life space; social boundary-phenomena often develop between these two regions, where the individual opinions about the function of another group come to exist. Thus, social boundary-phenomena in such areas play an important role in the social order, and their nature must be inquired into more closely by psychological and other means. The writer of this paper is of the opinion that it is profitable to develop the topological and dynamic mode of thought in dealing with these social boundary-phenomena. The present paper is a first attempt in this direction.
II
Among the aborigines of Formosa (Takasago race), there are two tribes: the Atayal and the Saisiat living as neighbours in the north, as the map in the Japanese text shows. Between them, there occurred frequent struggles for power since olden times, and on the whole, so far as their history is concerned, the Atayal are strong and large, the Saisiat weak and small. (In their prehistoric period, the Saisiat were very likely a big tribe, according to the survey, of the Institute of Ethnology of our University.) The Saisiat were not only attacked by the Atayal, but were also pressed by the Formosan-Chinese from the plains, and thus they were deprived of power on both sides.
On the last day of 1936, the Atayal had a population of 12,690 while the Saisiat had only 1,483 in the Sintiku Province where the writer made the following experiment. (Adding up the figures for other provinces, the Atayal: had a total of 36,128 as against the Saisiat: 1,486.)
III
According to observations of the character of these two tribes made by Japanese writers many years ago, the most remarkable difference between them:-
Atayal: “Intrepid by nature, ashamed of cowardice; cowardly conduct before the enemy being despised in this society.”
Saisiat: “In bravery inferior to the Atayal, possibly on account of their small population and of the pressure exercised on them by stronger enemies since olden times. The distinguishing quality of the able-bodied-man in this tribe is fleet-ness of foot. This is, of course, necessary for attack, but as far as this tribe is concerned, it is esteemed valuable to escape when a battle is lost......”
Interpreted according to the present writer's terminology, the writers found their difference in character to consist in the way they developed the social boundary-phenomena between them and their enemies, i. e. the difference lies in their dynamic properties in account with the topology of their behavioural field, in short in their behaviour-direction.
IV
The writer has made the ‘flower-experiment’ after Dembo with male adult subjects of the two tribes: the subject is required to take from a table about one meter high, a flower with his hand, not putting his foot out of a square frame of bamboo laid on the floor about 1 and 1/5 ineter, away from the table. The number of the subjects were Atayal: 16, Saisiat: 19.
The most noticeable result of this experiment is that the difference in the behaviour-direction between the two tribes was found in the experimental field of the problem as set by the experimenter, i. e. manner in which they deal with the boundary (with resistance) between them and their aim, and the nature of the boundary-phenomena is not the same in the two tribes.