1883 E. Ray Lankester in Encycl. Brit. XVI. 652/1 [article Mollusca] Important distinctions which obtain amongst the various ‘introverts’ or intro- and e-versible tubes so frequently met with in animal bodies.

1885 Encycl. Brit. XIX. 431/1 [article Polyzoa] The anterior portion of the body of the polypide can be pulled into the hinder part as the finger of a glove may be tucked into the hand. It is, in fact, an ‘introvert’.

1916 C. E. Long tr. C. G. Jung Coll. Papers Analyt. Psychol. 349 An Extravert can hardly conceive the necessity which compels the Introvert to conquer the world by means of a system.

1918 P. Blanchard in Amer. Jrnl. Psychol. Apr. 163 Jung's hypothesis of the two psychological types, the introvert and extrovert,—the thinking type and the feeling type.

1920 Challenge 21 May 44/2 All works of the imagination are conceived by men of the introvert type.

1923 T. P. Nunn Education 145 An ‘introvert’ concerned mainly with his own feelings and thoughts.

1925 C. Fox Educ. Psychol. 254 The introvert abstracts from the object and deals with it by concepts concentrating upon the inner world of thought.

1934 Brit. Jrnl. Psychol. July 26 They were noticeably more introvert, schizoid and desurgent in temperament.

1955 L. Langstroth Struct. of Ego vii. 82 This question of the relative strength of the social and biological selves suggests at once Jung's broad division of personalities into two main types: the introvert and the extrovert.

1957 H. J. Eysenck Dynamics Anxiety & Hysteria vi. 213 The introvert, as we have seen, is socialized.

1960 Encounter 15 47 The introvert-intellectual is the hero of several of Buchan's works.

1967 J. M. Argyle Psychol. Interpersonal Behaviour iii. 50 Experiments with schoolchildren show that introverts respond better to praise.

1946 R. P. Basler in W. S. Knickerbocker 20th Cent. Eng. iii. 392 In the snugness of introvertish isolation, there is always time, an eternity for continual deception and indecision.

1671 A. Woodhead in tr. Life St. Teresa Pref. 28 The Soul being straight, introverted..into itself, and easily conforming to God's will and time.

1822 W. Hazlitt Prejudice in Table-talk (1852) 85 The less we look abroad, the more our ideas are introverted, and our habitual impressions..grow together into a kind of concrete substance.

1834 H. N. Coleridge Introd. Greek Poets (ed. 2) 26 The mind of the old poets was rarely introverted on itself.

1785 [implied in: W. Cowper Task iv. 633 His awkward gait, his introverted toes, Bent knees, round shoulders, and dejected looks. (at introverted adj. 2a)].

1883 E. Ray Lankester in Encycl. Brit. XVI. 652/2 [article Mollusca] It cannot be completely everted owing to the muscular bands, nor can it be fully introverted owing to the bands which tie the axial pharynx to the adjacent wall of the apical part of the introvert.