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to acquire, to present, sign, to strengthen, to occur, to condition

1. The visible ... of ageing appear earlier in some individuals than in others.
2. Even a temporary isolation from the group ... the tendency towards conformity.
3. Experiments have demonstrated that infants as young as ten days may be ... to suck at the sound of a buzzer if this is frequently ... just before the bottle is inserted in the mouth.
4. In prematurely born infants of 32 weeks responses to light, sound and even taste may....
5. In the book «Personality and Psychotherapy» J. Dollard and N. Miller tried to apply laws of learning to the problem of how neurotic behaviour is ....