日比野 治雄

In this study, our aim is to clarify the color combination rules of the human-preferred Papilionidae butterflies as aesthetic objects. A set of 118 butterfly images, including color polyphenism from the 47 Papilionidae species that are generally preferred by humans, was selected. These images were classified using hierarchical cluster analysis based on similarities of lightness, chroma, and hue attributes in CIELAB space, determined using histogram intersection. Then, the color distributions and combinations in each cluster were analyzed using a Gaussian mixture model and the color combination types defined in the present study. Accordingly, we obtained the following main color combination rules of human-preferred Papilionidae: (a) dominant low lightness and contrasting lightness components, (b) dominant low chroma and similar chroma components, and (c) dominant orange to yellow-green hue and similar hue components. These rules partly agree with the robust harmony principles found in previous research. We infer that the cognitive effects concerning the processing fluency through these color combination rules influence human aesthetic responses.

Trypophobia refers to disgust for a cluster of objects, and is considered an extension of disgust for dangerous objects. Furthermore, trypophobic images possess certain spatial properties that can induce perceptually unpleasant states (i.e., visual discomfort). We examined whether trypophobia is associated with disgust sensitivity, empathic traits, and visual discomfort. Japanese adults (n�=�126) completed four scales: the Trypophobia Questionnaire, which measures trypophobia proneness the Disgust Scale-Revised, which measures disgust sensitivity the Interpersonal Reactivity Index, which measures empathic traits and the Visual Discomfort Scale, which measures proneness to visual discomfort. Trypophobia proneness was found to be predicted by Core disgust sensitivity (i.e., threat of disease), Personal Distress (i.e., the empathic trait of self-oriented emotional distress), and proneness to visual discomfort. We suggest a number of potential factors relating to individual differences in trypophobia and the possible cognitive and perceptual mechanisms underlying trypophobia.

人間の肌に蓮の花托(花弁・おしべ・めしべを取り去った部分) をコラージュした画像は「蓮コラ」と俗称されており，肌から多数の蓮の実が覗いている様は体験的に不快を喚起することが知られている。また蓮コラと似た斑点模様を持つ広告やプロダクトに対しても不快感を訴える者がいる。蓮コラや斑点模様が不快を喚起する要因として，嫌悪を感じやすい傾向である「嫌悪感受性」との関連が挙げられている。蓮コラと嫌悪が密接に関わっているならば，蓮コラージュ対象が人間にとって身近であればあるほど不快感が増す可能性がある。また嫌悪的な蓮をある対象にコラージュすると，嫌悪が増幅する現象が蓮コラであると考えられる。よって本研究では蓮コラによる不快現象を確認し，更にその不快感が蓮コラージュ対象の違いによるものだと推察し検討を行なった。人間と動物の蓮コラに対する不快感評定の結果， 蓮コラは蓮単体よりも不快感が強かった。しかし人間と動物の間に不快感の差は見られなかった。この結果は蓮コラージュ対象への心理的距離の近さによって部分的に説明されることが示唆された。本研究は蓮コラや斑点模様による不快の予防と軽減に繋がると考えられる。

Patients with migraine are susceptible to visual discomfort. Some painters who suffer from migraine express their migraine experience and visual discomfort through their paintings, which we refer to as migraine art. Several famous painters (e.g., Picasso) also have been reported to suffer from migraine; therefore, we refer to their paintings as "possible-migraine art." Although paintings with excessive energy at mid-spatial frequencies are uncomfortable to view, it remains unknown whether migraine art and possible-migraine art contain spatial characteristics that contribute to visual discomfort. We performed a spatial-frequency analysis on migraine art, possible-migraine art, and non-migraine art images. The results revealed that migraine art contains more energy at mid-spatial frequencies than non-migraine art. Possible-migraine art also contains this spectral characteristic. We propose that painters who suffer from migraine may utilize rather than avoid spatial characteristics that contribute to visual discomfort.

Although the perception of visual motion modulates postural control, it is unknown whether illusory visual motion elicits postural sway. The present study examined the effect of illusory motion on postural sway in patients with migraine, who tend to be sensitive to it. We measured postural sway for both migraine patients and controls while they viewed static visual stimuli with and without illusory motion. The participants' postural sway was measured when they closed their eyes either immediately after (Experiment 1), or 30 s after (Experiment 2), viewing the stimuli. The patients swayed more than the controls when they closed their eyes immediately after viewing the illusory motion (Experiment 1), and they swayed less than the controls when they closed their eyes 30 s after viewing it (Experiment 2). These results suggest that static visual stimuli with illusory motion can induce postural sway that may last for at least 30 s in patients with migraine.

In cataractogenesis, vision deteriorates as the crystalline lens becomes hazier. This leads to opacity and eventually to light obstruction. Intraocular lens (IOL) implantation has become popular in recent years for the treatment of severe cataracts. Visual acuity and color perception are recovered in most patients following surgery. However, it was hypothesized that the recovery process may entail a hypersensitivity to visual stimuli, resulting in adverse symptoms similar to those in migraine patients. In this study, we conducted structured interviews with nine cataract patients regarding visual discomfort following lens implant surgery. Although most of the patients reported improved vision and quality of life, four described increased hypersensitivity to visual stimuli. Thus photosensitivity and visual discomfort may accompany the improvement in visual function after IOL implant surgery.

Geometrical patterns such as stripes and grids induce various types of visual perception including movement, fatigue, and discomfort. Although these patterns can induce discomfort, especially in migraine patients, they can also be used for art and design to induce good feelings. In the present study, we attempted to measure these perceptions quantitatively and systematically in migraineurs and headache-free controls. In the experiment, participants evaluated discomfort, brightness, fatigue, flicker, motion, and the beauty of square and sine wave patterns by using magnitude estimation. The results showed that all of the evaluation values, except for beauty, increased in both groups as the grids became smaller; moreover, brightness increased significantly by a greater amount in migraineurs than in controls. The square waves with the smallest grids induced both beauty and discomfort in both groups, and the sine-wave patterns induced stronger fatigue and motion perceptions than square-waves patterns in both groups.

The demand for a new type of studio unit has increased gradually with the diversification of resident types. However, the current floor plans of studio unit do not utilize the benefit of an open plan in small areas. Thus, the purpose of this study is to propose several guidelines for the planning of studio unit that correspond to residents' needs in order to facilitate the benefit of open plans, such as efficiency and multi-purpose use within a small area. As the results, the design guidelines of planning studio unit could be suggested through five cases. These findings show that, for a better understanding of studio unit, further research by increasing the number of subjects and diversifying the dwelling size will be needed.

Shading is one of the typical depth cues generally used in letter illustrations and designs. Among the various kinds of shading directions, we humans are most familiar with shading in the right-bottom direction. In the present study, we investigated the perceptual effects of the shading directions using letters of alphabets as stimuli. In Experiment 1, we used 26 capital letters and 4 geometric figures in the six shading directions, which means that there were 180 conditions (i. e., (26 letters +4 figures) ×6 shading directions). For each condition, we measured the reaction times for perceiving the stimulus. The results indicated that it takes longer for subjects to recognize simple letters and figures. In Experiment 2, we focused on preferences and readabilities of the stimuli, using eight capital letters in four shading conditions. As the results, we found that the right bottom shading was evaluated as the highest (i. e., the most beautiful, positive, and readable). It is plausible that the results are related to our familiarities with the right bottom shading.