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                            Survey:
                             The least structured and least personal form in the interview range of instruments used in social research, which takes the form of a type of questionnaire. 
 
                            10-year rule:
                            A rule of thumb that suggests that in order to become outstanding in any skill in the top 1% of performers around ten years dedicated practice is required. 
 
                            Teratogens:
                            A class of environmental hazards which cause marked abnormalities in the fetus during pre-natal development and which are can be caused by the use of harmful drugs or substances, such as thalidomide and cocaine, cigarette smoking and heavy use of alcohol. 
 
                            Three-term series problem:
                            A kind of deductive reasoning problem, which has two statements about three people or objects that can be ordered according to a relation such as height. 
 
                            Tilt after effect:
                            The temporary visual distortion of perceived orientation following adaptation to an oriented stimulus. 
 
                            Time theory of pitch perception:
                            The idea that perceived pitch depends upon the temporal pattern of activity in the auditory nerve. 
 
                            Universal grammar:
                            (UG) the theory, suggested by the American linguist Noam Chomsky, that all children possess an in-built faculty for spoken language, a theory which is disputed by others, who consider that children are born only with general learning processes which enable them to learn language amongst other things. 
 
                            Verbal channel:
                            In an interview situation, the spoken element, as opposed to the various other non-verbal channels of communication used. 
 
                            Visual illusion:
                            A mental distortion of perception, sometimes misleadingly called an optical illusion, where visual stimuli are seen incorrectly. 
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