I think the study is likely invalid . . . Romanian orphanages are likely hell-holes where the kids are not properly cared for. The study probably, realistically, only shows that children that are ignored, not given good medical attention, and not given good nutrition have lower IQ’s.
We adopted our son who spent the first two and a half years of his life in a Russian orphanage, and although he was well cared-for and well-fed in a group of 12 children with typically three daytime caretakers, I know some other kids who at the age we took him home were speaking in full, grammatically-correct sentences, whereas he was still speaking maybe a few dozen generally mushy Russian words.
And he’s pretty darn smart to begin with, and it shows very well now that he’s nearing four years old and speaking English quite well. I suspect that his language development would have been much further along had he been fostered instead of in an orphanage for those 2 1/2 years.
One thing we noticed, as did other people we know, when you walk into an orphanage is how QUIET it is compared to a similar-sized group of family-raised kids.