Length of the span
Estimates for the length of human attention span are highly variable and depend on the precise definition of attention being used.
- Transient attention is a short-term response to a stimulus that temporarily attracts/distracts attention. Researchers disagree on the exact amount of human transient attention span.
- Selective sustained attention, also known as focused attention, is the level of attention that produces the consistent results on a task over time. Common estimates of the attention span of healthy teenagers and adults range from 10 to 20 minutes; however, there is no empirical evidence for this estimate. People can choose repeatedly to re-focus on the same thing. This ability to renew attention permits people to 'pay attention' to things that last for more than a few minutes, such as lengthy films.
Attention span, as measured by sustained attention, or the time spent continuously on task, varies with age. Older children are capable of longer periods of attention than younger children.
For time-on-task measurements, the type of activity used in the test affects the results, as people are generally capable of a longer attention span when they are doing something that they find enjoyable or intrinsically motivating. Attention is also increased if the person is able to perform the task fluently, compared to a person who has difficulty performing the task, or to the same person when he or she is just learning the task. Fatigue, hunger, noise, and emotional stress reduce the time focused on the task. Common estimates for sustained attention to a freely chosen task range from about five minutes for a two-year-old child, to a maximum of around 20 minutes in older children and adults.
After losing attention from a topic, a person may restore it by taking a rest, doing a different kind of activity, changing mental focus, or deliberately choosing to re-focus on the first topic.