The same is true of even higher order, more abstract combinations of traits. Digman's (1997) alpha, which he felt tended to reflect successful socialization, must be understood as a summary of separable, though related, processes. High scores on alpha can be obtained in many different ways (contributors to high scores could include measures of traits such as neuroticism, psychoticism, cognitive distortion, identity disturbance, affective instability, narcissism, alienation, and many others), so variation on alpha does not describe a psychological process and therefore cannot describe a causally active process. Only measures of unidimensional constructs can lay claim to explaining psychological processes and hence to explaining possible causal activity.
