The Nature of the Choice to Focus

At the bottom of page 58 of OPAR it states “the choice to focus, Miss Rand used to observe, is like throwing a switch; it may be compared to starting a car’s motor by turning on the ignition.” This description implies that focusing is binary – either you are “on” or “off”. More convincing to me is the statement further up on page 58 “To ‘focus’ one’s mind means to raise one’s degree of awareness. As mentioned on page 56 “As there are degrees of visual acuity, so there are degrees of awareness at the conceptual level.” The choice to focus, as I understand it through introspection, is more like deciding how much to “bear down” mentally to achieve a conceptual task ie how much mental effort to expend. It is akin to deciding how much weight to lift at the gym. Thus, if I am reading a light novel or a topic I am already familiar with, it takes less mental effort than reading a new article on a conceptually demanding one. If so, the choice to focus is more the choice on whether to go up on the continuum of mental awareness than whether to be simply “on” or “off”. What do you think?