正解: CCorrect: C
最も強力なのは達成経験（mastery experience）です。自分の力で困難を乗り越えた実体験は、他の情報源よりも持続的で確かな効力感をもたらします。The most powerful source is mastery experience. Direct experience of overcoming difficulty through one's own effort produces more durable and convincing efficacy beliefs than any other source.
Bandura（1977, 1997）は自己効力感の源として、達成経験、代理経験、言語的説得、生理的・情動的状態の4つを挙げ、なかでも達成経験が最も強力であると述べました。自分の行動が結果に結びついたという直接の証拠は、他者の言葉や観察よりも信念を強く更新するからです。代理経験は「自分と似た人」であるほど効果が高まりますが、達成経験ほど確実ではありません。言語的説得は短期的な後押しになる一方、実際の失敗で容易に打ち消されます。身体状態の管理は効力感の解釈に影響を与える補助的な要因です。したがって、自信を育てたいなら「小さく確実に成功できる課題」から始め、達成を積み重ねることが理にかなっています。Bandura (1977, 1997) identified four sources of self-efficacy: mastery experience, vicarious experience, verbal persuasion, and physiological and emotional states. He argued that mastery experience is the most powerful, because direct evidence that one's own actions produced results updates beliefs more strongly than the words or examples of others. Vicarious experience is more effective when the model is similar to oneself, but it is less reliable than mastery. Verbal persuasion provides a short-term boost but is easily undone by actual failure. Managing physiological states is a supporting factor that shapes how people interpret their own efficacy. Consequently, the sensible way to build confidence is to start with tasks that are small enough to succeed at reliably and accumulate achievements.
達成経験を重視しすぎると、失敗のリスクがある挑戦を避け、確実に成功できる簡単な課題ばかりを選ぶ「成功の罠」に陥る可能性があります。また、過去の成功が新しい領域での効力感に自動的に転移するとは限りません。Overemphasizing mastery experience can lead to a "success trap" of choosing only easy tasks that guarantee success while avoiding risky challenges that would actually stretch you. Past success also does not automatically transfer to efficacy in a new domain, so an accomplished expert can feel like a beginner again after a career change.
課題の難易度を段階的に上げる「足場かけ」を設計し、少し背伸びした挑戦を小さく分割して達成を積み重ねましょう。加えて、代理経験（自分に近い人の成功事例）や信頼できる人からの具体的なフィードバックを組み合わせると、新領域でも効力感を早く立ち上げられます。Design scaffolding that raises task difficulty gradually, breaking slightly ambitious challenges into small achievable steps and recording each completed step. Combining this with vicarious experience (success stories of people similar to you) and specific feedback from trusted people helps build efficacy quickly in new domains without waiting years for major wins.