In reply to the second question, some teachers stated that they never made a mistake, while others admitted failure in one case out of three. Still others said, "Once in ten years," "once in twenty years," "once in a thousand times," etc. As Binet remarks, the answers to this question are not very enlightening. In the first place, the teacher as a rule loses sight of the pupil when he has passed from her care, and seldom has opportunity of finding out whether his later success belies her judgment or confirms it. Errors go undiscovered for the simple reason that there is no opportunity to check them up. In the second place, her estimate is so rough that an error must be very great in order to have any meaning. If I say that a man is six feet and two inches tall, it is easy enough to apply a measuring stick and prove the correctness or incorrectness of my assertion. But if I say simply that the man is "rather tall," or "very tall," the error must be very extreme before we can expose it, particularly since the estimate can itself be checked up only by observation and not by controlled experiment. The teachers' answers seem to justify three conclusions:-- 1. Teachers do not have a very definite idea of what constitutes intelligence. They tend to confuse it variously with capacity for memorizing, facility in reading, ability to master arithmetic, etc. On the whole, their standard is too academic. They fail to appreciate the one-sidedness of the school's demands upon intelligence. In a quaintly humorous passage discussing this tendency, Binet characterizes the child in a class as _dénaturé_, a French word which we may translate (though rather too literally) as "denatured." Too often this "denatured" child of the classroom is the only child the teacher knows. 2. In judging intelligence teachers are too easily deceived by a sprightly attitude, a sympathetic expression, a glance of the eye, or a chance "bump" on the head. 3. Although a few teachers seem to realize the many possibilities of error, the majority show rather undue confidence in the accuracy of their judgment. BINET'S EXPERIMENT ON HOW TEACHERS TEST INTELLIGENCE.[9] Finally, Binet had three teachers come to his laboratory to judge the intelligence of children whom they had never seen before. Each spent an afternoon in the laboratory and examined five pupils. In each case the teacher was left free to arrive at a conclusion in her own way. Binet, who remained in the room and took notes, recounts with playful humor how the teachers were unavoidably compelled to resort to the much-abused test method, although their attempts at using it were sometimes, from the psychologist's point of view, amusingly clumsy. [9] See p. 182 _ff._ of reference 2 at end of this book.