Effects of pupil area on impression formation in pupil expression media

Abstract

Pupils give favorable impressions to humans depending on their size. Focusing on effects of the pupil size, various pupil sizes were evaluated using human images as stimulations in previous researches. However, it is difficult to express an extreme pupil size in a face image due to a limited area of eyes. In addition, the evaluation of pupil size itself is hard because impressions in human images are formed depending on not only the pupil size but also other facial parts. In order to evaluate impressions of the pupil size itself, it is desirable to extract only the pupil and exclude other facial parts. In this study, we analyzed impressions on various pupil sizes that combined the dilation / contraction using two kinds of pupil expression media that have been developed so far. In the analysis, the impression evaluation obtained by the SD method was factor-analyzed. As the result of factor analysis, three factors were extracted: acceptability, reliability, and curiosity. Acceptability and reliability factors had a certain peak, and curiosity factor was proportional to the pupil size. These analysis results demonstrated that a certain dilated area of pupil could form a favorable impression regardless of pupil expression media.