A new study rather dramatically illustrates the effect of early environment on IQ. Benedict Carey reports the study in the NYT story: Orphanages Stunt Mental Growth, a Study Finds
Psychologists have long believed that growing up in an institution like an orphanage stunts children’s mental development but have never had direct evidence to back it up.
Now they do, from an extraordinary years-long experiment in Romania that compared the effects of foster care with those of institutional child-rearing.
. . .
On I.Q. tests taken at 54 months, the foster children scored an average of 81, compared to 73 among the children who continued in an institution. The children who moved into foster care at the youngest ages tended to show the most improvement, the researchers found.
The comparison group of youngsters who grew up in their biological families had an average I.Q. of 109 at the same age, found the researchers, who announced their preliminary findings as soon in Romania as they were known.
This has some relevance for the IQ debate, but more importantly, it will put pressure on governments, like that of Romania, that forbid foreign adoptions of orphans.