**5. Discussion**

In this section, we would like to conduct an interdisciplinary analysis of how this metaphorical and psychological transfer could have occurred. This interdisciplinary approach consists of five parts: The first is the consideration of the inter-sensory transition phenomenon through the concept of synesthesia; the second is an artistic approach based on the characteristics of the paintings that we used in our experiments; the third is the consideration of the characteristics of deep neural networks in connection with the concept of synesthesia and the characteristics of our paintings; the fourth includes the limitations of this study and the future directions of development; the fifth is the overall blueprint of our research.

First, we deal with synesthesia by focusing on the transition of senses. References [15–17] show that media art can give potential cognitive and emotional impacts. We would like to discuss why this effect could occur. Synesthesia is a blending of the senses in which the stimulation of one modality simultaneously produces sensations in a different modality. Synesthesia is known to affect four percent of the population. However, via color–alphabet experiments with 400 people, studies [73] have shown that people without synesthesia perceive synesthesia but do not consciously recognize it. In other words, non-synesthesia implies that synesthesia is being perceived unconsciously. In particular, the study by [74] dealt with implicit associations between color and sound, particularly showing that various color properties can be mapped to acoustic properties, such as tone and volume. The study by [75] showed that the properties of sounds can be associated with colors. The study by [76] also demonstrated empirical investigations of the associations between auditory and visual perception. Based on these experimental results, transitions between implicit senses are possible; for example, value and hue can be mapped onto acoustic properties, such as pitch and loudness, pitch can be associated with color lightness, loudness can be mapped onto greater visual saliency, high loudness can be associated with orange/yellow rather than blue, and chroma can have a relationship with sound intensity. The following sections cover the features of our artworks.

Second, the artworks used in our experiments were Impressionistic paintings. Impressionism is a trend in art that focuses on colors, lighting, and textures, and it is characterized by the ability to describe nature in the changing colors of light and to accurately and objectively record the visible world using the momentary effects of colors and shades. In particular, three of our four paintings were by Van Gogh, and he is known as a postimpressionist. Van Gogh tried to thicken paint through the Impasto technique to express the maximum texture and create a three-dimensional effect. In addition, Van Gogh did not describe objects in the same way, but captured his emotion and feeling very strongly through the touch of his brush. This distorted form, intense color, and simplification of the form were sought to express emotions. The other painting was "Woman with a Parasol in a Garden". Renoir was an early impressionist who understood how to express the effects of light, and was known to use black to express shadows. Therefore, the paintings we used are from the early to the late Impressionist period, and they are characterized by their good representation of colors, light, and texture. Therefore, we selected our paintings in consideration of these features. The characteristics of the paintings were analyzed and the possibilities of sensory transitions were addressed.

Third, we discuss how a deep neural network was able to recommend music and paintings in the above consideration. The study by [77] dealt with the perspectives of beauty, sentiment, and remembrance of art in deep neural networks. The study by [77] quantitatively and qualitatively analyzed three subjective aspects of human consciousness: image features in relation to aesthetics, sentiment, and memorability. This study indicated that the CNN considered features of various aspects, such as color, intensity, harmony of colors, object emphasis, pattern, art style, semantics, genre, and content. This study also addressed how deep neural networks judge and remember emotional and artistic values by exploring predicted aesthetic and emotional memory scores in the context of art history. In particular, these experiments also showed that aesthetic and emotional scores and color correlations are consistent with common assumptions. These experimental results show that deep neural networks consider factors that can cause sensory transference. Therefore, these features make our sensory transition possible.

Fourth, we address the limitations of our experiment and the directions of future study. There is a limitation in that no global solution was shown. The limitations can be seen from three perspectives: The first is that our research only dealt with Impressionist paintings from an artistic point of view. Therefore, further study is needed as to whether such studies can be applied to different artistic styles beyond Impressionism. The second is the problem of generalization; this study is not representative of the general population because the experiments were conducted on people in their 20s in Korea. In addition, research should be conducted on whether the experimental results are universal or if they are due to social learning. If the results obtained are due to social learning, extended studies should also be carried out from various perspectives, including culture, age, and local areas. Future research will therefore need to extend these local solutions into a global solution. The third is the effectiveness of media art, which can have potential cognitive and emotional impacts. However, our research focused on the potential cognitive impacts of the experiments. Therefore, we measured emotional impact with the F-score, the most representative and implicit single scalar value. These representative features of F-score can be influenced by various factors, such as emotions and environments, as well as by potential cognitive factors. Therefore, more detailed measurements should be studied in the future.

Fifth, our experiment was intended to enhance the experience of appreciation of media art through the effect of visual and auditory transitions. The transitions of these senses can be expected not only in vision and hearing, but also between various other senses, such as vision and smell or vision and touch. In this study, we aimed to create a platform that guides blind people through sensory transition they appreciate media art. Finally, we hope that this multi-sensory experience will be harmonized and become abundant in media art. Furthermore, we hope that our proposed method will be applied to multi-modal media art platforms to help visually impaired people appreciate artworks.
