Three researchers from Institut Polytechnique Paris analyzed player performance from around 24,000 professional chess matches over a period of 125 years, which involved examining the moves of 4,294 players—20 of whom were world champions. By comparing each player’s chess moves against optimal moves proposed by a digital chess engine, the researchers discovered that performance ability reached a peak at about age 35. Most players were able to preserve that level for around 10 years. But after age 45, their skill level started to decline. Changes in cognitive ability reflect changes in the brain’s structure and chemistry, says University of Waterloo psychology professor Myra Fernandes, PhD. “As we enter midlife (mid-30s to 40s), the overall volume of the brain begins to shrink,” she explains. “The rate of shrinkage, which is due to the normal aging process and cell death (senescence), increases around age 60.”
Understanding Cognitive Decline
This cell death doesn’t occur uniformly throughout the brain. “Some regions experience more and faster rates: the prefrontal cortex, cerebellum, and hippocampus show the biggest losses, and this worsens with further advancing age,” says Fernandes. “Thus the functions subserved by these areas become selectively impaired.” This means that while some cognitive abilities decline with advancing age (during your 20s and 30s, according to a 2009 study), others actually remain stable or even increase, according to the American Psychological Association. “With age, committing new information to memory and recalling names of new acquaintances can take longer,” Fernandes says. “Differentiating similar events, that occurred at different points in time, is particularly problematic. For example, remembering where you parked your car on a specific occasion can sometimes be harder when the context is familiar: did I park near the food court today? Or was that where I parked last week, and today I parked closer to the bus stop?” Working memory, which is one’s ability to hold a piece of information in mind, such as a phone number, or password, also declines with age, Fernandes says. But a number of other cognitive processes are well-maintained into advanced age. “Our vocabulary and crystallized intelligence, which includes general knowledge of the world and knowledge acquired through hobbies, professions, and other sources, tend to increase throughout the lifespan and only show declines in very advanced age,” says Jennifer Coane, PhD, associate professor of psychology at Colby College in Maine. Procedural memories (overlearned motor routines) like remembering how to skate, how to ride a bike, or tie a shoe, remain largely intact, Fernandes adds. Overall, the field of cognitive aging research offers many examples of declines in some cognitive processes and preservation in others. “A positive cognitive change that occurs in aging is that older adults tend to have what is referred to as a ‘positivity bias,’ meaning they attend to positive stimuli more and are more emotionally regulated than younger adults,” says Coane.
What Affects Brain Power As We Age?
A number of factors affect cognitive ability besides biological age, Coane adds. Physical health, in particular cardiovascular health, is associated with cognitive functioning, as is access to nutritious food and clean water. “As we age, we also tend to experience decreases in vision and hearing; both of these are associated with poorer performance in cognitive tasks,” says Coane. “Hearing loss in particular seems to be associated with more rapid cognitive decline.” Other relevant factors include level and quality of education (research indicates that those who have more years of education tend to perform better on cognitive tasks as they age), and factors that increase the body’s stress response, such as poverty, racial discrimination, violence, lack of security, loneliness, and poor sleep—these can also have significant adverse effects on someone’s cognitive health.
Up For Debate
The specific age at which cognitive decline begins is a matter of some debate, largely because there are many discrepancies in published research. “There is a lot of variability across individuals, so it’s important to consider how different patterns of age-cognition present in the same individual who is re-tested over several years,” says Fernandes. Discrepancies may also stem from which cognitive abilities are evaluated or whether between-group comparisons are made – these tend to under-report age-related cognitive declines, Fernandes notes. Experts also recommend reading and learning new skills or tasks to enhance mental stimulation. And maintaining positive social relationships keeps people more alert, motivated, and cognitively stimulated.
