Detecting Changes of Affects by Accelerated Plethysmogram

We have tried to detect changes of affects by measuring accelerated plethysmogram. We gave 9 kinds of mental stimuli to 22 subjects and measured their accelerated plethysinograms. We chose the power spectrum of a-wave intervals of accelerated plethysmogram as an index to detect changes of affects. The accumulated powers in a low frequency region measured in many kinds of stimuli were significantly smaller than that measured in the light chatting condition which we assume as a base condition in this research, whereas the accumulated powers in a high frequency region measured in some passive kinds of stimuli were significantly bigger than that measured in the base condition. We also analyzed the correlations of the accumulated powers between measured in the different stimuli. The correlation coefficients of the powers between almost all stimuli in the low frequency region are high, whereas these in the high frequency are high between some kinds of similar stimuli.