Calendrical Calculation

Are you familiar with the term calendrical calculations? It's a term that describes an ability to name the day of the week for a specific date. Being able to name the day of the week for any date in the distant past or future is a fairly common savant ability. Interestingly, studies have shown that individuals who have calendrical calculation skills often have IQs that are below average, but not always. (http://www.sciencedirect.com/science/article/pii/S0160289699000288)