This study is a tactile EEG experimental study to sense the surface of interior finishing materials by rubbing it with palm or fingers. It includes experienced recognition as it incorporates participants'' subjective assessment of touch of feel.
This study approaches people''s comfortableness with interior finishing materials through relaxation or arousal. Therefore, the purpose of this study lies in measuring changes in central nervous system, i.e. changes in brainwave, identifying which finishing materials are comfortable, in other words, relaxible if touched, adding meaning to physical functions of the materials to be applied into interior space when manufacturing them, and providing effective indoor environment.
Subjects for experiment are those who want to participate in this experiment. Participants pass through one-man preliminary experiment. A total of 46 male and female adults aged 20 to 43 years participated. In nature of brainwave, subjects from various fields of major and occupation constituted the participant group.
The electrode sites for measuring brainwave are FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2, F7, F8, T3, T4, T5, T6, CZ, FZ, and PZ, and to these, AFZ is added.
Eight (8) tactile stimulations of indoor finishing materials, in other words, metallic material, plastic film, lumber, stone, glass, silk wallpaper, fabric, and paint were touched and felt. ‘α-wave against β-wave’ appearing as a result of a mental process related to physiological response in human''s brain was studied intensively and subsequently, changes in ‘relative θ-wave’, ‘relative α-wave’, ‘relative β-wave’, and ‘relative γ-wave’ were analyzed and observed.
For experimental analysis, TeleScan 3.10 was used to collect and analyze data and SPSS statistical program (ver. 22) was used to calculate mean and standard deviation from all data measured. Also for verifying if each finishing material is statistically significant, one-way ANOVA was conducted for data processing.

As a result, αp/βp , R.θp , R.αp , R.βp , and R.γp appeared statistically significant as brainwave appearing in the part of brain of each channel for eight (8) finishing materials and the following conclusions could be obtained from the findings obtained.

First, in tactile stimulation of interior finishing materials, stable waveform was more prevalent in smooth finishing materials than in rough ones and arousal waveform was more prevalent in smooth finishing materials than in rough ones. But, the finishing materials that might cause tension like stone although the smoothness of the surface of the finishing materials was well-treated were excluded. Such warm finishing materials as fabric although they show EEG characteristics close to arousal because they have much unevenness on the surface of finishing materials are considered to have rather brought about convenient relaxation. Plastic film appeared as the most relaxed finishing material in EEG characteristics caused by tactile stimulation and silk wallpaper as the most aroused one in the same. Silk wallpaper is a finishing material evaluated as the roughest one in terms of feeling of the surface by most subjects.

Second, in tactile stimulation on the surface texture of interior finishing materials, rough surface is uncomfortable and aroused because senses felt from hand cause sense of pain (sense that recognizes pain). Brainwave response depends significantly on roughness and smoothness of surface and also depends on warmness and coldness of temperature. Brainwave response sometimes appeared mixed in the smoothness and roughness on the surface of finishing materials and in the smoothness and warmness on the same, and other times appeared mixed in the warmness and roughness on the surface of finishing materials and in the coldness and smoothness on the same. But, these appeared more clearly when the difference in texture or unevenness on the surface of finishing materials was obvious.

Third, in the characteristics of tactile brainwave on the surface texture of finishing materials, it was analyzed that it is not that all that are smooth and soft are comfortable and all that are rough and hard are uncomfortable, and it was analyzed that appropriate combination of temperature and surface texture should be achieved to give comfortableness to people. Here, temperature can be considered as the degree of psychological stability when people touch the surface of finishing materials. But, the degree of such ‘stability’ depends on person, which thus leads to limitations.

Fourth, taken together within the scope of this study, tactile sensing of tactile stimulation on the surface of interior finishing materials showed contrasting response in the difference between smoothness and roughness of surface and in the difference between warmness and coldness of surface, caused relaxation wave and arousal wave in the brainwave, and showed difference in the response. But, this study has rather limitations because senses from surface texture depend on individual difference or person.

Fifth, this study approaches comfortableness through relaxation and arousal. α-wave increases and β-wave decreases, thus leading to relaxation and α-wave decreases and β-wave increases, thus bringing about arousal. This suggests that even when α-wave only increases and β-wave remains, it brings about relaxation and even when β-wave only decreases and α-wave remains, it brings about relaxation. Therefore, it was judged that it would be good to see two parameters of α-wave and β-wave, in other words, relaxation and arousal as comfortableness indicators for the interior finishing materials in terms of proportion.

Sixth, psychological shapes of experience recognition on the surface texture of interior finishing materials were not evenly reflected in brainwave. It was analyzed that physical properties of surface texture seem to have a stronger influence on the characteristics of tactile brainwave on the surface texture of finishing materials than experience recognition. In other words, the texture properties of an object currently contacted are reflected in brainwave rather than previous experience related psychology because the surface of finishing materials is directly contacted.

In conclusion, emotion caused by tactile stimulation can become a cause that may form psychological stability or generate anxiety. Stimulus related to various tactile senses that may cause feelings in humans is associated with various types of stimulus such as environmental changes and physical contact. This will stimulate human brain and produce another psychological form of experienced recognition. Therefore, if more efficient indoor environment is provided based on such mental process studies in order to apply finishing materials into space, it will have a positive impact on the formation of human feelings. Also, if such characteristics of brainwave can be reflected in a variety of finishing materials, ‘space user''s convenience’ will be enhanced more.
To this end, the purpose of putting the results of this study into practical use is to make an approach in various directions for applying various finishing materials used in interior space, for applying into where requires relaxation or arousal if contacted, for manufacturing and using living furniture, for manufacturing and using furnitures and fixtures, and for manufacturing and using other various goods and to achieve effective utilization that may satisfy functionality in a fundamental way by incorporating transcendental human nature into space.