A group of 165 Romanian orphans were studied. They were adopted by families in the UK from ages 4, 6, 11, 15. A control group of 52 UK children were adopted at the same time.
At first, the Romanian adoptees showed signs of intellectual impairment. Those adopted before six months had higher IQs and as their age progressed their IQs were lower. Also, the children adopted after six months showed disinhibited attachment (attention-seeking, clinginess).