An academic hood is a garment that drapes from the back and shoulder of the wearer, and signifies what advanced degrees are held (e.g., Master of Divinity, etc.) A hood is generally black, with the colored lining showing outward. The colors signify the degree area (e.g., Divinity). An academic hood is worn in church services when “choir dress” is worn. This comes from English cathedral practice, with choir dress consisting of cassock, surplice, tippet, biretta (for some), and academic hood.
The only time an academic hood would be worn at Grace would be at solemn Evensong (sung Evening Prayer).