As the brain ages, it becomes more difficult for it to shut out irrelevant stimuli—that is, it becomes more easily distracted. Sitting in a restaurant, having a conversation with your table partner right across the table from you, presents as a new challenge when the restaurant is buzzing with activity.
However, the aging brain does not have to be the distracted brain. Training the mind to shut out irrelevant stimuli is possible, even for the older brain.
Brown University scientists conducted a study involving seniors and college-age students. The experiment was a visual one.
Participants were presented with a letter and number sequence, and asked to report only the numbers, while simultaneously disregarding a series of dots. The dots sometimes moved randomly, and at other times, moved in a clear path. The latter scenario makes the dots more difficult to ignore, as the eye tends to want to watch the dots move.
The senior participants tended to unintentionally learn the dot motion patterns, which was determined when they were asked to describe which way the dots were moving. The college age participants were better able to ignore the dots, and focus on the task at hand (the numbers).
Another study also examined aging and distractibility, or an inability to maintain proper focus on a goal due to attention to irrelevant stimuli. Here, aging brains were trained to be more focused. The researchers used older rats, as well as older humans. Three different sound were played during the experiment, with a target tone presented. Awards were given when the target tone was identified and the other tones ignored. As subjects improved, the tasks became challenging, with the target tone becoming less distinguishable to from the other tones.
However, after training, both the rats and the humans made fewer errors. In fact, electrophysiological brain recordings indicated that neural responses to the non-target, or distracting, tones were decreased.
Interestingly, the researchers indicated that ignoring a task is not the flip side of focusing on a task. Older brains can be just as efficient at focusing as younger brains. The issue in aging brains, however, lies in being able to filter out distractions. This is where training comes in: strengthening the brain’s ability to ignore distractors; not necessarily enhancing the brain’s ability to focus.
The major highlights of the study include training older humans with respect to enhanced aspects of cognitive control, and the adaptive distractor training that sought to selectively suppress distractor responses.