PSYCHOLOGY OF MENTAL DEFICIENCY
89
Fig. 7. An Experiment in Action with the Ergograph.
| Mental Age | Capabilities | Class | ||
| 8 years, | Errands. Light work. Makes beds. | Low | Moron. | |
| 9 years, | Heavier work. Scrubs, mends, lays bricks, cares for room with simple furniture. | |||
| 10 years, | Good institution helpers. Routine work. | Middle | ||
| 11 years, | Fairly complicated work with only occasional oversight. | |||
| 12 years, | Uses machinery. Cares for animals. No supervision. Can not plan. | High | ||
Figs. 8 and 9. Ergograms. Records of a normal man and of a defective boy, the latter showing characteristic irregularities.
The ergograph was devised by Mosso, an Italian psychologist, and is used to measure muscular fatigue. A weight is lifted with one finger every alternate second until the muscle is tired out. Each lift is recorded on a vertical line and the sum total of lifts and lengths of lines are indicative of muscular action and voluntary control.
