Twins are often psychic twins, but that does not necessarily mean that individually they are psychics too.
Because of their similarities, it is easier for psychic twins to 'tune in' into each other's psychic energy frequencies. However, if psychic twins don't develop their skills as other psychics do, they won't be able to be 'in tune' with the world around them any more than a normal person can.
It is not the similarity of appearance that enables the connection between psychic twins. Genetic similarity, similarity of physical and social environment, similarity of upbringing, and also 'cosmic alignment' (so to say), are a number of factors that strongly guide psychic twins to develop similar ways of being, thinking, and feeling.
This similarity of inner processes is what enables the psychic connection between psychic twins. This chance to reflect upon oneself more closely may give psychic twins an additional opportunity to make a few steps along the psychic path.