Dr. mecina, who is concerned with how vision is processed consciously and unconsciously, is studying

The answer to fill the blank space is "Dual Processing".
Complete sentence will be as below:
Dr. Mecina, who is concerned with how vision is processed consciously and unconsciously, is studying  "Dual Processing".

Dual processing means that the information is usually processed on separate conscious and unconscious tracks.

answer; ///i believe that it means; ///you pay no customs duty on the chocolates;