Children of wealthy parents are more likely to grow emotionally attached to a blanket or soft doll than poor children, a New Zealand psychiatrist says, but the attachment doesn't lead to any problems.

"Perhaps parents who are free from financial worries are more relaxed and indulgent of infantile habits," Pauline A. Mahalski of the University of Otago writes in the Journal of Child Psychiatry. "Or perhaps they are less likely to satisfy their children's needs for warmth and companionship," leading the child to take up with a doll or blanket.

Mahalski and other researchers found that, for the most part, there were few differences between children who carried blankets around and those who didn't. Those with blankets "appeared to mature and adjust like other children," they write.

As many boys as girls were attached to soft objects, they note, and in families that moved often, such attachments were rare, "thus supporting the old adage that rolling stones gather no moss."

The scientists reviewed literature about such attachments and also studied 160 New Zealand children to try to figure out why some carry blankets and others don't, but they found no sure explanation.

One thing was clear, though: Children who carried soft objects around also were more likely to be thumb-suckers. And in one study -- though not all of them -- thumb-suckers tended to be "moody and unsociable when they were older."