As we get older, we seem to lose patience, as well as most of us expecting to find it harder to concentrate. Now scientists believe they have uncovered the reason why – and it lies in the way our brain develops as we age. They say it gets harder to focus, without being distracted, past the age of 55, particularly when under stress, because of the way our brain changes over time.
A study has found stress has much less of an effect on young people, who are able to focus on the task at hand and block out unnecessary distractions. By contrast, scans showed that older individuals lose these skills. The study, led by the University of South Carolina, put participants aged 55-75 in a stressful situation then asked them to pick the clearer of two black and white photographs. When the results were compared to those of a group aged 18-34, the older group was worse at focusing, taking longer to find the answer. MRI scans found older adults, under stress, showed less activity in that part of the brain which enables us to pay attention and ignore competing thoughts or distractions. Younger adults, by contrast, showed no differences.
Professor Mara Mather, a co-author of the study, said: ‘Trying hard to complete a task increases emotional arousal so when younger adults try hard, this should increase their ability to ignore distracting information. But for older adults, trying hard may make both what they are trying to focus on and other information stand out more.’
The experiment enlisted 24 participants in the older group and 28 in the younger. Their task, repeated 160 times, was to identify the clearest image out of two pictures of a building and an object. The correct answer flashed up for just a tenth of a second. To place extra pressure on them, participants were threatened with electric shocks. The results, published in Nature Human Behaviour, found younger people answered, on average, 143 milliseconds faster. The study’s authors think this is because the part of the brain which controls the ability to focus under pressure appears to weaken with age.
The pathways between this area and the parts of the brain involved in looking at images and places and controlling what we pay attention to, and what we ignore, showed less activity in the older adults. These areas are also linked to developing Alzheimer’s disease and other forms of dementia. Professor Mather said: ‘Deciphering exactly how these changes in the brain occurs as we age could one day help us uncover how to protect the brain from cognitive decline.’
I find this all rather frightening – to think what old age has in store for us. So far, apart from the occasional stress of maintaining an active life, the only adverse effect I feel, from time to time, is the inability to sleep as well as I did in my younger days. Otherwise, I have so far escaped any loss of concentration or the ability to focus when required. And all I can say is ‘Hallelujah’!