Cognitive specialization is a theory that states that learning certain skills inhibits the ability to learn related but dissimilar skills. Study findings have shown that a person's ability to observe one's own mental processes, as well as that of others, might be an evolutionary trait, not just a common social one.[1]
The typical example is language. As you learn one language, you may find it more difficult to learn other languages, particularly ones that are dissimilar to the first.