5.3.1. The Base-Level Problem Space (BLS)Like all other behavior, immediate response occurs in a problem space. This is the space in which the working-memory elements created by perception (via encoding perhaps) become available for cognitive consideration; and in which the commands are issued that result (via decoding perhaps) in the motor system taking action. Both input and output occur in a single space, since otherwise taking an impasse would also be required for taking an action, and this would imply some permanent lack of knowledge. This space is called the base-level problem space (BLS), because it is the one that governs interaction with the external world (Rosenbloom, Laird, & Newell, 1988a).