Attention

Attention is the mental process in which a person concentrates awareness on a specific object, issue, or activity and excludes other potential stimuli ^* from the environment. While the human brain has amazing capabilities for processing information, it also has limited capacity. A person cannot attend to all the information being received through the five senses (sight, hearing, taste, smell, and touch) at any one time.

What Parts of the Brain Are Involved
in Paying Attention?

Neuroscientists (nor-o-SY-in-tists), or scientists who study the brain and nervous system, believe that attention is largely a function of the brain's reticular activating (re-TIK-yoo-lur AK-ti-vay-ting) system, or RAS. This system includes a group of nerve fibers located in several parts of the brain, including the thalamus ^* , hypothalamus ^* , brain stem ^* , and cerebral cortex ^* . The RAS seems to account for the shifts in people's level of involvement with their surroundings, which ranges anywhere from full attention to sleep. When the system is fully operating, a person is awake, alert, and attentive; this would be the case when a person is listening to an interesting lecture or taking an important test. When the RAS is less active, a person is tired or inattentive. The highway signs urging drivers to "Stay Awake - Take a Break" actually are related to the RAS; it is much more difficult for people to pay attention when they are tired.

Within the RAS, the thalamus appears to play a key role in the moment-to-moment changes in the focus of attention. The thalami and cerebral cortex cooperate to register any incoming sensory signals, evaluate their contents, and mobilize brain resources in response to the demands made. Put simply, the thalami receive the messages that come through a person's senses and then relay the information to the proper receiving areas in the brain.

Chemical messengers known as neurotransmitters (nor-o-TRANZ-mit-erz) are also involved in the process of paying attention. In fact, all of the systems within the brain depend on chemicals that pass electrical signals from nerve cell to nerve cell. A test known as electroencephalography (e-LEK-tro-en-sef-uh-LAH-gru-fee), or EEG, can measure electrical signals within the brain. Two transmitter substances, noradrenaline (nor-uh-DREN-uh-lin) and dopamine (DOH-puh-meen), play important roles in helping people stay alert and attentive. The medicine methylphenidate (meth-il-FEN-ih-date; better known by its brand name, Ritalin ^® ) is used to treat Attention Deficit Hyperactivity Disorder and is thought to work by regulating the levels of key neurotransmitters in the brain, particularly dopamine. After taking the medicine, people who have difficulty focusing their attention are better able to concentrate on a task.

This is an overly simplified explanation of a complex process. There are other parts of the brain and nervous system that play a role in the process of paying attention. For example, a group of structures in the middle of the brain compose the limbic (LIM-bik) system, which is linked to various emotions and feelings such as fear, pleasure, and sadness. These structures are thought to play some role in how people decide to focus their attention. For example, when a student sits at a desk to read a school textbook, a variety of complex emotions may play a role in her decision to focus on the text: pleasure in the subject matter, fear of doing poorly on the next test, desire to perform well during class discussion, and so forth. To focus in on the task at hand, she must tune out all other stimuli, such as the other books scattered around the room, the sound of children playing outside, the color of the desk pad, and the ticking of the clock. Attention is not always under a person's control, however. If someone comes bursting into the room or turns on a stereo at full volume, the student's attention would likely be drawn away from the book. Thus, attention may be captured by an unexpected event rather than voluntarily directed toward it.

Do Television and Video Games Affect Attention?

Some experts have argued that watching too many fast-paced television programs and video games may actually increase the likelihood of attention problems. If the brain becomes accustomed to constant stimulation by rapidly changing visual effects, it may easily become impatient with tasks that require closer attention. Television also makes fewer demands on attention than do reading, studying, or playing a game. Without enough of these more challenging activities, the brain may "get out of shape."

However, the reverse may be true. Children and adults with limited attention resources may be attracted to intense stimulation and therefore may be captured by television or video games. Less intense activities may not hold the focus of individuals with attention deficits. More research is needed to better understand this issue.