Daris, a marathon runner, is trying diligently to read his textbook, but he keeps finding himself preoccupied with his upcoming race. he is frustrated because he has had to go back and reread sections the textbook in order to really understand the material. daris seems to be having difficulty with

Daris seems to be having difficulty with encoding. 

Encoding is an important step in the process of forming a memory. It is the process wherein information (such as matter from a textbook) is converted into a form that can be stored in the brain, and recalled and retrieved on future occasions. Encoding can be done through various methods using visual, auditory and mnemonic devices.