Underlying mechanisms of visual comfort and discomfort: A study using psychophysical experiments and brain activity measurements

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K14257
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 10040:Experimental psychology-related
• Research Institution: Hiroshima University
• Principal Investigator: Yoshimoto Sanae 広島大学, 人間社会科学研究科(総), 助教 (80773407)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 視覚 / 情動 / 感性 / フリッカ / 不快感 / 色覚 / 脳活動 / fMRI

Outline of Final Research Achievements

In this study, we aimed to reveal the underlying mechanisms of visual comfort and discomfort using psychological experiments and brain activity measurements. For this purpose, we measured the discomfort elicited by flickering stimuli with two changing colors over time. We found that discomfort level increased as the perceived chromatic contrast increased. However, when one of the two colors was a highly saturated red, strong discomfort was consistently induced regardless of chromatic contrast. Meanwhile, brain activity during stimulus observation measured using fMRI showed a positive correlation between activity in the posterior part of the brain, including the visual cortex, and discomfort. These results suggest that the strength of brain activity on visual processing involved in color perception induces discomfort, and that vivid red colors changing over time are specifically associated with discomfort.

Free Research Field

実験心理学

Academic Significance and Societal Importance of the Research Achievements

本研究から、感情喚起に関わる視覚刺激の特徴の一端を明らかにした。とりわけ健常者に対し不快感情を喚起する視覚刺激は、光過敏性発作を誘発する可能性があることが知られている。日本放送協会と日本民間放送連盟による「アニメーション等の映像表現に関するガイドライン」では、子ども向けのアニメ番組が光過敏性発作を引き起こした事例に基づき、鮮やかな赤色の使用を避けるよう注意喚起されている。本研究成果は、人間の視覚特性と感情の繋がりに関する理解を深めるだけでなく、例えばガイドラインにおいて使用を避けるべきとされている「鮮やかな赤色」に明確な基準を設けるなど、映像の安全性の向上に寄与すると期待される。