Another line of activity in the Vineland research department has been the gathering of statistics on physical growth of defectives. A report of this work may be summed up as follows:
The lowest grades (idiots) are from two to four inches shorter and from five to fifteen pounds lighter than normal children of corresponding age.
The middle grades (imbeciles) are less than half this amount below normal, while the highest grades (morons) do not differ appreciably from normal children except that there is a tendency to become heavy.
Commenting on these results Dr. Goddard writes, "Normal children begin to grow fast at about eleven years. Among defectives this acceleration does not come until two years later, but when it does come it is a greater acceleration than in normals. This is not yet accounted for but it suggests that it may have an important bearing upon our treatment of school children at that critical age of eleven to fifteen."
The difficulty with these measurements, like all others on normal children, is the fact that they are based on one measurement of a large number of individuals and not on repeated measurements of the same individuals. An investigation soon to be published by the writer shows that two characteristics of growth of which Dr. Goddard has found true of deficient children, are characteristic of normal children as well. That is they naturally form two groups at adolescence, the short boys and girls beginning their rapid growth from one to two years later than the tall boys and girls, and there seems to be a direct correlation between rapid growth at adolescence and the advent of puberty for both boys and girls, the shorter ones maturing later than the tall ones.
Classification of Mentally Deficient Children
Dr. Howe, who is best known from his work with the blind, attempted to group all mentally deficient children under the headings "simpletons," "fools" and "idiots," but the most widely accepted classification to-day is that of Dr. Barr, of the Elwyn Training School, Pennsylvania, who classifies them as "feeble-minded," "imbeciles" and "idiots."
A new classification has recently been adopted by the American Association for the Study of the Feeble-minded. It is functional rather than physiological and is as follows:
| Mental Age | Capabilities | Class | ||
| Under one year, | Helpless. | Low | Idiot. | |
| 1 year, | Feeds self. Eats everything. | Middle | ||
| 2 years, | Eats discriminatingly. | High | ||
| 3 years, | No work. Plays little. | Low, | ||
| 4 years, | Tries to help. | Imbecile. | ||
| 5 years, | Only the simplest tasks. | Middle | ||
| 6 years, | Tasks of short duration. Washes dishes. | |||
| 7 years, | Little errands in house. Dusts. | High | ||
