In this last figure of speech we have already suggested that the so-called fixation-point of consciousness denotes in general only the ideal middle point of a central region, within which several impressions can be clearly and distinctly apprehended. So in one row of beats the beat heard at a certain moment would lie within the fixation-point; yet the immediately preceding beats are still clear and distinct enough, in order to be included within the same narrow region, which contrasts with the more extensive field by reason of its greater clearness. The psychological process agrees also in this respect with the expressions we have borrowed from the sense of sight, where we have a single point of the field of vision as fixation-point, around which a great number of impressions may be clearly perceived. Only because of this are we able to apprehend a larger image in a single moment, e.g. to read a word. For this central part of the field of our consciousness, which immediately surrounds the subjective fixation-point, the practical necessity of language has already coined a word, which has been accepted by psychology. We call that psychical process, which is operative in the clear perception of a narrow region of the content of consciousness, attention. When impressions, or any other content, at a certain moment are remarkable for their special clearness in comparison to the other elements in consciousness, we say that they lie within the focus of attention. Keeping to our former figure, we imagine this as the central region that surrounds the subjective fixation-point, and it is cut off by a more or less clearly defined boundary-line from the larger and darker field that surrounds it. And this immediately gives rise to a new experimental problem, which forms an important supplement to the above-described measurement of the whole scope of consciousness. The problem consists in answering the question that immediately arises, How big is this narrower scope of attention?