W - cognitive explanation of AN - evidence is correlational. Can't be sure whether cognitive distortions lead to AN or if AN leads to cognitive distortions. If the former is true, the theory is validated. If the latter is true, it means that the cause of anorexia lies elsewhere. AN might therefore be due to genetic factors such as inheriting a faulty EPHX2 gene. As supporting evidence is undermined, the theory based on it decreases in validity