EDUCATIONAL PSYCHOLOGY 



read; when the mental age is much less than this, their 

 reading progress is slow. On the other hand, a child who 

 enters school at the age of six or seven but with a mental 

 age of nine or ten years is able, if given a chance, to cover 

 all the work of the first three grades in the first school 

 year. 



The educational and social significance of the I.Q. lies 

 in the fact that for a given subject it tends to be fairly 

 constant throughout the period of growth. The child 

 whose I.Q. is 75 at the age of six is not found with an I.Q. 

 of 125 or 150 a few years later. Increases, decreases, and 

 fluctuations of I.Q. do occur, but in the large majority of 

 cases they are rather small in amount, rarely more than 

 15 or 20 points, and on the average not more than 5 or 6 

 points in a total range among school children from I.Q.'s 

 below 50 to I.Q.'s above 150. 



The child below 60 I.Q. is ordinarily classifiable as 

 feeble-minded and is not likely ever to develop beyond 

 the mental age of eight or nine years, as intellectual 

 growth pretty well ceases by the age of fifteen or sixteen 

 years. Subjects in the range between 60 and 80 I.Q. may 

 or may not be able to make their way in the world, depend- 

 ing largely on their emotional, volitional, and other 

 non-intellectual equipment. Those of 75 to 90 I.Q. may be 

 classified as normal but dull, those of 90 to 110 I.Q., as 

 average normal, those of 110 to 130 as superior, and those 

 above 130 as very superior. About ten children in a thou- 

 sand test as low as 70, and about an equal number as high 

 as 130. On the average four or five in a thousand are above 

 140 I.Q. About 15 per cent test below 80 I.Q. and about 

 an equal number above 120 I.Q. It is from those above 115 

 or 120 I.Q. that we get the majority of our college students. 

 Those as low as 90 are rarely able to graduate from high 

 school, and those as low as 80 rarely progress beyond the 

 seventh or eighth grade. 



[Ill] 



