The Two-Year Window

investigators had observed that the orphans had a high frequency of serious developmental problems, from diminished IQs to extreme difficulty forming emotional attachments. Meanwhile, imaging and other tests revealed that some of the orphans had reduced activity in their brains. The Bucharest project confirmed that these findings were more than random observations. It also uncovered a striking pattern: Orphans who went to foster homes before their second birthdays often recovered some of their abilities. Those who went to foster homes after that point rarely did.

This past May, a team led by Stacy Drury of Tulane reported a similar finding—with an intriguing twist. The researchers found that telomeres, which are protective caps that sit on the ends of chromosomes, were shorter in children who had spent more time in the Romanian orphanages....It was the clearest signal yet that neglect of very young children does not merely stunt their emotional development. It changes the architecture of their brains.

http://motherjones.com/kevin-drum/2011/11/two-year-window