What is the span of attention, often called the magical number, in Miller's studies?

1. Box 4.2 reports Miller's finding on how many items people grasp from a brief exposure. 2. It states that span of attention varies within the limit of seven plus or minus two. 3. This range is popularly called the magical number in the same paragraph. 4. So the magical number is seven plus or minus two. _Source: syllabus Psychology Ch 4 "Sensory, Attentional and Perceptual Processes", p. 65, Box 4.2 Span of Attention_