To begin, here are some Fun Psychology Facts:  

People who were asked to describe a face after seeing it are worse at recognizing the same face later.

People who are asked to describe a wine after drinking it are worse at recognizing the same wine later.

People who are asked to give reasons for their preferences among a collection of jellies are worse at identifying their own preferences among those jellies.

This effect, known as Verbal Overshadowing, occurs primarily when a principally non-verbal process is disrupted by a task which involves verbalization.  The above generalizations (and Verbal Overshadowing effects more generally), do not occur among what we can term "Verbal Experts": individuals who are as good at verbalizing the relevant process as they are at doing it implicitly or automatically.  This seems like it will be very important to keep in mind when cultivating our own Rationality.