Young and old: who performs more consistently?
A new study examining day-to-day variability in adults’ cognitive performance shows that older adults are more consistent than younger ones
How variable is our cognitive performance from one day to the next? Do older adults vary more in their performance than younger people? Scientists from Berlin, Frankfurt, and Sweden have examined these questions in the COGITO Study. The Director at the Munich Center for the Economics of Aging at the Max Planck Institute for Social Law and Social Policy comments on what the findings mean with respect to the productivity of older adults in their working life.
Sometimes it’s just not your day: First you cannot remember where you put your car keys, and then you forget about an important meeting at work. On days like that, our memory seems to let us down. But is it really the case that we are cognitively fitter on some days than on others? Are there actually good and bad days for cognitive performance? Florian Schmiedek, Martin Lövdén, and Ulman Lindenberger examined this issue with the data set of the COGITO Study, an investigation conducted at the Max Planck Institute for Human Development in Berlin.
The scientists’ findings show that variability in cognitive performance does indeed exist. Our personal impression that a whole day is either good or bad, however, is often wrong. Most performance fluctuations occur within shorter periods of time. What seems like a good or bad day is often due to good or bad moments that do not make the whole day’s cognitive performance any better or worse than that of an average day. “True variability from day to day is relatively low”, says Florian Schmiedek, who planned and carried out the COGITO Study together with Lövdén and Lindenberger.
The results of a comparison between age groups were particularly surprising: In all nine cognitive tasks assessed, the older group actually showed less performance variability from day to day than the younger group. The older adults’ cognitive performance was thus more consistent across days. This picture remained unaltered when differences in average performance favouring the young were taken into account. “Further analyses indicate that the older adults’ higher consistency is due to learnt strategies to solve the task, a constantly high motivation level as well as a balanced daily routine and stable mood,” explains Florian Schmiedek.
The findings are of importance for the debate about older people’s potential in working life. “On balance, older employees’ productivity and reliability is higher than that of their younger colleagues,” says Axel Börsch-Supan, Director at the Munich Center for the Economics of Aging at the Max Planck Institute for Social Law and Social Policy in reaction to the findings of the COGITO Study. “One of our studies in the car production industry has shown that serious errors that are expensive to resolve are much less likely to be committed by older staff members than by their younger colleagues. Likewise, in other branches of industry that we have studied, one does not observe higher productivity among the younger relative to the older workers,” states the scientist, who studies productivity of the labour force in aging societies.
In the internationally unique COGITO Study, 101 adults aged 20 to 31 years and 103 adults aged 65 to 80 years worked on twelve different tasks on 100 days. The tasks tested their perceptual speed, episodic memory, and working memory. Repeating the tasks across 100 days enabled the researchers to assess the participants’ learning improvements as well as their day-to-day performance fluctuations and to compare the performance of the two age groups.