But that would be an edge case. I would have assumed that identical twins behave similarly. How do they find enough neglected twins to make a reliable conclusion.
I’ve known three sets of identical twins. In each case the personalities were very different. Outgoing vs reserved, aggressive vs laid back, etc. I could easily see one wanting to be held more than the other.
Anecdotal, but... My (fraternal) twins have very distinct and different personalities. One requires an order of magnitude more attention than the other. We try to make up the difference, but it's hard.
