The sameness of twins seems more likely to be 'parallelism' than true communication to me. If they grow up together they are going to have very similar personalities and simply tend to come to the same thoughts in the same way. If you can show communication at a distance that's another matter. But just because they have 'the same thoughts' when in the same situation I would not ascribe that to any 'psychic' powers or relationship. I have heard that some ESP studies have been done with twins, but I think the results were inconclusive.