Japanese has three sets of demonstratives: ko-series (nearer to the speaker), so-series (nearer to the hearer; moderately away from the speaker), a-series (far from the speaker). The influence of operability and the dehumanization of the hearer on the deictic use of ko, so, a was examined in production task with 30 college students. The conditions investigated were as follows: (a) the speaker used a pointer, enhancing the speaker's operability; (b) the hearer was seated beside the speaker, decreasing the speaker's range of operability; (c) instructions were given by a tape recorder, allowing the dehumanization of the hearer; (d) a control condition. The ko area was enlarged in condition (a) and reduced in condition (b). Use of so ref eying to objects near the hearer decreased in condition (c). Use of so in the case of moderately away from the speaker was not affected by the location and the dehumanization of the hearer. The hypotheses were largely confirmed.