1. Attention is the concentration of awareness on some phenomenon to the exclusion of other stimuli and determines consciousness. It can be voluntary, requiring conscious effort, or involuntary, arising without effort.
2. Factors that influence attention include the nature, intensity, size, contrast, location, repetition, motion, and form of stimuli as well as an individual's interests, motives, mental set, past experiences, emotions, and habits.
3. The span of attention refers to how long stimuli can be focused on before a break is needed. Visual attention span is brief while auditory span is slightly longer, especially with rhythm. Sustained attention maintains continuous concentration on a subject.