Application of near-infrared spectroscopy to measuring of attractiveness of opposite-sex faces

Brain imaging technology employing near-infrared spectroscopy (NIRS) has great potential in various applications to daily life, by virtue of offering handy equipment and an easy measurement method. In this paper, we propose a novel application of NIRS to evaluation of feeling. As compared with an electroencephalogram, the NIRS offers easier attachment of probes on the scalp, because it does not require any paste. As compared with the magnetic resonance image system, the NIRS can detect hemodynamic response by much smaller equipment. To examine the suitability of NIRS for evaluation of feeling, we measured hemodynamic responses in the left anterior frontal cortex, which we then correlated with reported assessments of facial attractiveness. Oxy-hemoglobin in the area increased when the subjects evaluated the faces as unattractive, and the amount of increase measured in each trial was proportional to the degree of unattractiveness. This result indicates the availability of NIRS to real-time evaluation of feeling.