Shyness

Research indicates a positive correlation between childhood fearfulness and the development of shyness.^[4] Some studies suggest that higher levels of cortisol in shy children are associated with increased susceptibility to illness.^[5]

Several genetic links to shyness are current areas of research. Mouse models have also been used, to derive genes suitable for further study in humans. One such gene, the GAD gene, which is involved in producing GABA (a chemical that helps regulate brain activity and anxiety), has so far been shown to have some association with behavioral inhibition (a tendency to experience distress in new situations).^[6]

The genetics of shyness involves the study of candidate genes related to dopamine and serotonin regulation. Studies have identified modest correlations between shyness and specific variations of the DRD4 gene and the 5-HTTLPR (a region of the serotonin transporter gene). However, the influence of these individual genetic markers is considered small, and research into their connection with related conditions, such as social anxiety or obsessive-compulsive disorder, is ongoing.^[7][8] The long form of the 5-HTTLPR polymorphism (a common genetic variation) has been shown to be modestly correlated with shyness in grade school children.^[8] Previous studies had shown a connection between this form of the gene and both obsessive-compulsive disorder and autism.^[9]

Thalia Eley argues that only about 30% of shyness as a trait is genetically inherited, while the rest emerges as a response to the environment.^[10]

Characteristics such as excessive shyness, embarrassment, and social phobia are associated with erethism (a neuropsychiatric syndrome resulting from chronic mercury poisoning).^[11][12]

Evidence suggests an association between day length during pregnancy and the prevalence of shyness. A longitudinal study indicated that shorter day length during the midpoint of gestation may be associated with an increased probability of shyness in childhood.^[13]

There is an observed correlation between birth weight and shyness or cautiousness in children. Findings suggest that those born at low birth weights are more likely to be shy, risk-averse and cautious compared to those born at normal birth weights. However, this association does not establish a causal relationship.^[14]

内気さは学業成績の決定要因としても考えられます。研究によると、内気さと授業成績の間には負の相関関係があります。内気さが増すにつれて、授業成績は低下します。^{[ 19 ]}

While often colloquially equated with shyness, introversion is a distinct trait characterized by a preference for low-stimulation environments rather than social distress. Research by Bernardo J. Carducci states introversion is a preference for low-stimulation environments, whereas shyness involves a desire for social contact hindered by anxiety.^[20] Research using the statistical techniques of factor analysis and correlation has found shyness overlaps mildly with both introversion and neuroticism (i.e., negative emotionality).^[21][22][23] Low societal acceptance of shyness or introversion may reinforce a shy or introverted individual's low self-confidence.^[24][10]

Both shyness and introversion can outwardly manifest as socially withdrawn behaviors, such as tendencies to avoid social situations, especially when they are unfamiliar. Research indicates that shyness and introversion possess clearly distinct motivational forces and lead to different personal and peer reactions, and therefore cannot be described as theoretically the same,^[16][25][26] with Susan Cain's Quiet (2012) further discerning introversion as involving being differently social (preferring one-on-one or small group interactions) rather than being antisocial altogether.^[27]

研究によると、馴染みのある社会的状況と馴染みのない社会的状況とで、社会的に引きこもる行動に伴う心拍数の増加などの特有の生理的反応はない。しかし、非社交性は馴染みのない社会的状況への接触の減少につながり、内気さはそのような状況での反応の欠如を引き起こすため、内気さと非社交性は社交性の2つの異なる側面に影響を与え、別個の性格特性であることを示唆している。^{[ 25 ]}さらに、異なる文化では非社交性と内気さを異なる方法で認識しており、それが自尊心に影響を与える。集団主義文化では、内気さは集団の理想への順守と自己制御に関連するより肯定的な特性と見なされ、選択された孤立（内向的な行動）は集団の調和に対する脅威として否定的に認識される。そして、集団主義社会は内気さを受け入れ、非社交性を拒否するため、内気な人は内向的な人よりも自尊心が高くなる。^{[ 26 ]}一方、個人主義的な文化では、内気さは弱点や性格上の欠陥とみなされ、非社交的な性格特性（一人で過ごすことを好むこと）は自律性の価値を擁護するものとみなされるため受け入れられます。したがって、西洋文化では内気な人は自尊心が低くなりがちで、非社交的な人は自尊心が高くなる傾向があります。^{[ 16 ]}

臨床評価では、不安の重症度とそれに伴う機能障害の程度によって、内気と社交不安障害（SAD）を区別します。恥ずかしさや社会的回避などの特徴は共通していますが、SADは否定的な評価への恐怖が職業上または社会的な役割を妨げます。社交不安障害とは対照的に、正常な内気は通常、機能障害や社会的義務の広範な回避にはつながりません。^{[ 28 ]}しかし、1994年にDSM-IVが発行されたときには、括弧内に別の名称（社交不安障害）が与えられ、比較的よく見られるものになったと言われています。^{[ 29 ]}国立精神衛生研究所によると、米国成人の社交不安障害の生涯有病率は約12.1%で、過去1年間にこの障害を経験した人は推定7.1%です。^{[ 30 ]}内気な青年と大学生を調べた研究では、内気な人の12～18%が社交不安障害の基準を満たしていることがわかりました。^{[ 22 ] [ 31 ] [ 32 ]}

Physical symptoms of social phobia can include blushing, shortness of breath, trembling, increased heart rate, and sweating. In some cases, these symptoms are intense enough to cause a panic attack.^[2]

Social inhibition is the conscious or unconscious constraint of behavior for social reasons, often manifesting as shyness. There are different levels of social inhibition, from mild to severe. Social inhibition can be adaptive when it prevents harmful behavior, but may be maladaptive when it hinders constructive social participation, such as classroom discussion.

Behavioral inhibition is a temperament or personality style that predisposes a person to become fearful, distressed and withdrawn in novel situations. This personality style is associated with the development of anxiety disorders in adulthood, particularly social anxiety disorder.^[33][34]

Research consistently indicates no correlation between intelligence and shyness.^[36] While shyness may limit classroom engagement, longitudinal data suggests it is unrelated to actual academic knowledge or test performance.^[35] Social manifestations of shyness can affect how an individual's intelligence is perceived by others. In educational settings, shy children may find it difficult to demonstrate knowledge during verbal discussions, which may result in some educators underestimating their academic abilities.^[36][17]

In some Western cultures shyness-inhibition plays an important role in psychological and social adjustment. It has been found that shyness-inhibition is associated with a variety of maladaptive behaviors. Being shy or inhibited in Western cultures can result in rejection by peers, isolation and being viewed as socially incompetent by adults. However, research suggests that if social withdrawal is seen as a personal choice rather than the result of shyness, there are fewer negative connotations.^[41]

For Charles Darwin, shyness was an "odd state of mind", appearing to offer no benefit. Writer Joe Moran notes that since the 1970s, some psychological perspectives have increasingly viewed shyness through a pathological lens, though evolutionary perspectives also recognize the survival advantages of cautious temperaments.^[42] However, evolutionary survival advantages of careful temperaments over adventurous temperaments in dangerous environments have also been recognized.^[38][42]

In East Asian cultures shyness-inhibition in school-aged children is seen as positive. Those who exhibit these traits are generally accepted by peers and perceived as competent by educators, performing well in school and to showing well-being. Research in Chinese schools has suggested that shy-inhibited children are more likely to be nominated for leadership roles by their peers compared to Western cohorts. Being shy or inhibited does not correlate with loneliness or depression as in the West.^[41]

Cultural norms in some Hispanic contexts, such as rewarding students privately rather than publicly, may be misinterpreted as shyness by educators unfamiliar with these customs.^[43]

Socially close cultures based on agriculture (Kenya, India, etc.) experience lower social engagement than those in more open communities (US, Okinawa, etc.) where interactions with peers are encouraged. Children in Mayan, Indian, Mexican and Kenyan cultures are less expressive in social styles during interactions and they spend little time engaged in socio-dramatic activities.^[41]

In Italian culture emotional expressiveness during interpersonal interaction is encouraged. From a young age children engage in debates or discussions that encourage and strengthen social assertiveness. Independence and social competence during childhood is also promoted. In Italian contexts, social inhibition is often negatively appraised by parents and peers, as cultural norms tend to prioritize social assertiveness. Similar trends observed in both North American and Italian samples show that peers of shy and inhibited Italian children reject those who are socially fearful, cautious, and withdrawn. These withdrawn and socially fearful children express loneliness and believe themselves to be lacking the social skills needed in social interactions.^[44]