Abstract
Recent neuroimaging studies have revealed the involvement of the prefrontal cortex in the process of making an aesthetic judgment. One study reported that transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (lDLPFC) led to the significant enhancement of subjects' aesthetic judgment of visual images. We tested whether subjects' aesthetic judgments of visual and sensuous stimuli can be modulated by applying tDCS on the lDLPFC with the same parameters (2 mA, 20 min) used in a previous study. Sixteen subjects underwent the stimulation and sham conditions. We also measured subjects' feelings of pleasure, which has been reported to correlate with the feeling of beauty. We used six images from the International Affective Picture System (IAPS) with high valence ratings, and six IAPS images with middle valence ratings for visual stimuli; candies with six different kinds of flavors for gustatory stimuli, and stuffed animals with different kinds of textures for tactile stimuli (Brielmann & Pelli, 2017). Subjects rated their feelings of pleasure (1–10) during 30 s of stimulus exposure and in the following 60 s. At the end, they were asked to rate the beauty of the stimuli (0–4). The results showed that only the beauty of visual stimuli tended to receive lower ratings after stimulation. Bayes factor, an indicator of which among two competing models is a better data predictor, supported the decrease in beauty ratings through tDCS with high-valence and middle-valence IAPS images 1.4 and 1.9 times, respectively, more than the model that predicted that tDCS had no effect on rating. The ineffectiveness of tDCS on pleasure was 2.6 times higher than the model that tDCS had an effect on pleasure. Overall, our study suggests that effect of tDCS may be limited to certain modalities and that judgments of feelings of beauty and pleasure might involve independent processes.
Meeting abstract presented at VSS 2018