Digital Culture & AudioVisual Challenges

Summary:

A different number of studies examine how color impacts individuals' psychological functioning while also delving into the physiological changes that occur during exposure to color. In recent years, with the advancement of technology, various objective physiological measurement methods can be used on that scope. This paper examines the utilization of a low-cost electroencephalographic (EEG) tool on recording brain responses to RGB color stimuli, analyzing the results of a case study of a sample of 15 participants and the different brain patterns activated by exposure to the different color hues, that are presented to the viewer in an immersive VR environment as it isolates the person from the physical environment.

Objective:

Color evokes psychological and physiological responses in subjects. (Elliot, 2015). Johann Wolfgang von Goethe in his book "Theory of Colors" was one of the first to relate colors to emotional reactions (Elliot, 2015). However, Charles Féré was the first to undertake quantitative research on the impact of color on psychology. (Elliot, 2015). In recent years, there has been increasing interest in combining new technology (like EEG etc.) as methods that can detect differences in the physiology of a person.

The present study investigates one of the main characteristics of an image, the color and specifically the changes on the individual's physiology and reactions upon exposure to different hues (to the three primary colors: Red, Green, Blue (RGB)), from the perspective of brain activity within a virtual reality environment, by using a low-cost and portable EEG system. The purpose of the experiment is to verify if the observation of different colors can be detected in the selected EEG frequency combination while utilizing a low-cost tracking system, while comparing the recorded signals between a resting state and while viewing the different color stimuli.

The questions of the experiment are: a) Does exposure to different hues  (RGB) produce different EEG signal patterns for each of the colors, using a low-cost and portable system? b) Are there differences in the brain EEG power, modulated by exposure to the different primary colors (RGB)?

A number of researches have been conducted regarding the changes in human physiology upon exposure to different colors presented to the viewer either through screen projection or printed color sheets. This approach however uses an immersive environment on the research (it isolates the viewer who focuses on the presented visual elements), regarding the effect of colors on recorded EEG signals of the individual, whilst also the efficiency of the utilization of a low-cost portable EEG system upon that scope.

Method:

​The experimental session took place at the university, in the Multimedia Lab of ASFA. A final sample of 15 participants that didn’t have any vision impairment (9 women and 6 men) age ranging from 23-70 (mean age = 33.2, Standard Deviation = ± 11.96) participated, with no previous history of psychiatric or neurological diseases. All participants signed a consent form prior to their participation. The participants were sitting on a chair in a quiet room while wearing the OpenBCI Ganglion portable EEG system with 4 gold cup electrodes, while for the VR stimulation, a head-mounted display (HMD) of Oculus Rift CV1 was used. The stimuli were created using the Unity 3D Game Engine. The EEG recording involved an initial resting session of 60 seconds, serving as a baseline, followed by the RGB stimuli in a randomized order for 120 seconds per color, and for a total of 3 trials. Finally, the power of each EEG band [Delta (1-4 Hz); Theta (4-7 Hz); Alpha (8-12 Hz); Beta (13-24 Hz] was extracted from each electrode, it was normalized over the total power of the spectrum and subtracted from baseline.

Conclusion:

Color affects cognitive and emotional states and visual experiences. Color, among all visual elements, plays also an important role especially in art, but also in perception and interaction, while it can optimize the experience in an immersive environment or an artistic experience. Brain tracking technology is evolving rapidly and new possibilities are likely to become available to researchers (researchers either in the field of science or art) and artists.

By analysing the recorded EEG signals, we observe differences in the power and spatial distribution of the EEG bands and across different color stimuli. Notably, increased fronto-temporal Delta, reduced frontal Theta and Alpha but increased in the parietal area. Finally, increased Beta over the occipital side. Although we observe some differences per color stimuli, given the between-subject variability in the EEG, these results are preliminary and need to be translated with caution. 

References:

Beau Lotto, R., & Purves, D. (2002). The empirical basis of color perception. Consciousness and Cognition, 11(4), 609-629. doi:https://doi.org/10.1016/S1053-8100(02)00014-4

Elliot, A. J. (2015). Color and psychological functioning: a review of theoretical and empirical work. Front Psychol, 6, 368. doi:10.3389/fpsyg.2015.00368

Roy, S., Banerjee, A., Roy, C., Nag, S., Sanyal, S., Sengupta, R., & Ghosh, D. (2021). Brain response to color stimuli: an EEG study with nonlinear approach. Cogn Neurodyn, 15(6), 1023-1053. doi:10.1007/s11571-021-09692-z