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Trazo da personalidade que fai ao aprendiz pouco participativo na interacción social, opóñendose así ao aprendiz extravertido. Algunhas investigacións relacionan o grao de introversión e extraversión dos aprendices co éxito na aprendizaxe da segunda lingua; con todo, os resultados obtidos non son concluíntes.
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Rossier, J. 1975. “Extroversion-Introversion as a Significant Variable in the Learning of English as a Second Language.” University of Southern California. Dissertation Abstracts International 36: 7308ª-7309ª. (Tesis doctoral inédita).
Strong, M. 1983. “Social Styles and Second Language Acquisition of Spanish-Speaking Kinder-Garteners.” TESOL Quarterly 17: 241-258.