I'm not sure how anyone would really know how they were as an infant or how their parents were for that matter. Memory isn't simple and shifts. It is rare that anyone has pre-verbal memory that is explicit.

Still there are ways to infer things from adult behavior, and that includes also responses to tests that assess this type of thing. An avoidant attachment looks on the outside like the child is rejecting. However, the child actually registers distress on monitors. And even though avoidant it is still an attachment. I don't think there is such a thing as someone who does not have any type of attachment. Like people have said, infants are hard-wired to seek connection; it is a part of the survival of the species. And I believe that research shows that even if there are some differences, it is cross-cultural and hence universal. But it's not all nature necessarily. The infant's attachment style can be predicted, not only by very early observations, but actually by attachment tests that are done during pregnancy before the child is even born. That means that the mother may pass her own attachment style onto her infant or in some way cause the infant to develop a particular attachment style in response to hers. None of this is conscious, not even the behavioral interplay. And it is so overdetermined by factors that I'm not sure what exactly could be said for sure.