Page:Popular Science Monthly Volume 79.djvu/95

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91
PSYCHOLOGY OF MENTAL DEFICIENCY

PSM V79 D095 Object recognition test by the sense of touch.png

Fig. 11. An apparatus devised by Dr. Goddard for testing the ability to recognize objects by the sense of touch (stereagnostic sense).

younger, his development is arrested to the extent of one year, and similarly for two or three years. If he is unable to do the tests for more than three previous years, he is mentally defective and his mental age is determined by the tests which he can accomplish.

The test for a child of six years of age mentally is as follows: Shows right hand, left ear. Repeats sentences of 16 syllables. Distinguishes pretty from ugly or deformed faces, in pictures. Defines, in terms of use, the words table, chair, horse, mama. Performs three commissions given simultaneously. Knows age. Knows whether it is forenoon or afternoon.

The tests for seven are: Notes omission of eyes, nose, mouth or arms, from portraits. States number of fingers on right hand, left hand, both hands. Copies written sentences, with pen, so they can be read. Draws diamond-shaped figures from copy (child of mentality of six years can not do it. See illustrations, Fig. 4.) Repeat five numbers in order, when heard once. Describe a picture shown. Counts 13 pennies, one by one.

PSM V79 D095 Maze test for motor control.png

Fig. 12. The Maze Test for Motor Control. Reduced to one half. A device first used at Columbia University for testing the ability to trace the white line in a given interval of time. Frequent contact with the sides indicates poor motor control. High-grade feeble-minded children usually make from 60 to 100 contacts. The tracing reproduced was made by an epileptic and contains 84 contacts.

Mentally defective children seldom reach the mentality of a normal child of twelve years, who can meet the following requirements. Rearranges shuffled words of eight-word sentences. Repeats seven numerals in order, when heard once. Names three words that rhyme with obey, in one minute. Repeats, with no errors, sentences of 26 syllables. Infers a fact from given circumstances which indicate the fact.

Three hundred and seventy-eight defectives at Vineland have been tested with the complete Binet tests with the following results: