Cognitive Ageing: What Happens to Our Minds Over Time?

Every day, we perform hundreds of cognitive tasks, many of which we aren't even aware of. Whether it's remembering a friend's name, calculating the time on a watch, or recognizing a colour, our brain is constantly at work. Functional magnetic resonance imaging (fMRI) has shown that different areas of the brain become active depending on the task we're performing, underscoring that our mental abilities are comprised of various distinct cognitive functions.

Our cognitive abilities evolve throughout life, first growing and maturing as children and young adults, then experiencing gradual changes as we age. These shifts are influenced by a complex web of factors, from the maturation of our brain’s billions of interconnected cells to the natural process of aging.

In recent years, research has increasingly focused on the cognitive functions of those over 80, shedding light on how mental abilities change as we grow older.

Cognitive Changes with Age

As we age, some cognitive functions experience decline, but this doesn't necessarily mean that we lose the ability to perform daily activities. The changes we experience are often subtle and vary from person to person.

One of the most consistent cognitive changes with aging is cognitive slowing. For example, when asked to complete a task quickly, such as substituting numbers with symbols, 20-year-olds can perform the task almost 75% faster than 75-year-olds. This slowing also affects attention.

Elderly individuals may find it more challenging to grasp a phone number that's quickly recited, or struggle with multitasking, such as monitoring traffic while driving.

Attention and Working Memory

Attention, particularly the ability to multitask, often declines with age. Young adults are better equipped to divide their attention effectively, which is why they excel at handling tasks that require rapid switching between activities.

On the other hand, older adults may struggle with attention when switching between tasks or monitoring multiple elements at once—such as noticing pedestrians while driving or keeping track of different conversations.

Working memory, the ability to keep multiple pieces of information in mind, also peaks during young adulthood. As we get older, remembering things like a telephone number or mentally calculating a tip at a restaurant becomes more difficult. In clinical settings, working memory is often tested by asking individuals to recite a series of numbers backward. This task requires keeping the numbers in mind long enough to rearrange them mentally.

Memory and Word Recall

Memory tends to decline for many people as they age, but the nature of this decline can vary. The ability to recall new information, such as facts from a book or article, is most efficient in early adulthood and gradually declines, especially after age 40.

By age 70, an individual’s ability to remember information after a short period, like recalling a story 30 minutes later, is about 75% of what a young adult could recall. Interestingly, while free recall of facts might become harder, recognition memory—the ability to recognize something once seen—tends to remain intact well into older adulthood.

One common challenge older adults face is word-finding difficulties. Often experienced as a "tip of the tongue" moment, this happens when we know a word but cannot quite access it, even though it's stored in our memory. The word may come to mind later, but in the moment, it can be frustrating, particularly when we are actively trying to recall it.

Visual Perception and Executive Functioning

Older adults may also experience declines in visual perceptual abilities, particularly related to understanding spatial relationships. This decline can affect activities like driving—recognizing distances between objects or parallel parking can become more challenging. Additionally, executive functioning, which includes skills like decision-making, problem-solving, and planning, tends to slow with age.

Cognitive Optimism: Areas That Improve

While certain cognitive abilities decline with age, others remain stable or even improve. For example, vocabulary and general knowledge tend to be preserved throughout life and may even increase in middle age.

This is because they are strengthened by experience, which enhances reasoning and judgment. For instance, the ability to explain why foods need to be cooked is something that most adults, regardless of age, can do with ease based on years of life experience.

Social Cognition and Experience

Another area of cognitive resilience is social cognition—the ability to make accurate judgments about others based on social cues. As we age, we accumulate a lifetime of experiences that help us navigate social interactions.

Although older adults may process information more slowly, their social expertise often leads to better decision-making in familiar situations. This is a form of “wisdom” that comes from years of accumulated knowledge.

Factors Influencing Cognitive Decline

Not all individuals experience the same degree of cognitive decline as they age. Factors such as cognitive reserve, education, social engagement, and health play a significant role in how well cognitive functions are preserved. For instance, studies show that individuals with higher cognitive ability in childhood tend to have better cognitive outcomes later in life.

Similarly, maintaining an active social life, engaging in mentally stimulating activities, and having a purpose in life have all been shown to help preserve cognitive function.

Maintaining Brain Health

While some cognitive changes with age are inevitable, there are steps we can take to preserve our brain health. A healthy diet, physical exercise, and mental stimulation can help reduce the risk of cognitive decline.

Studies show that physical exercise not only benefits the body but also stimulates brain growth factors, while good nutrition—particularly limiting sugar and unhealthy fats—can protect against conditions like stroke and dementia.

Conclusion: Embracing the Aging Brain

As we age, our cognitive abilities undergo subtle changes that are often misunderstood. While some functions, like memory recall and multitasking, may slow down, others, such as vocabulary and social expertise, remain strong.

Understanding what normal cognitive ageing looks like, helps us with the assessment of mental capacity and it also helps us identify when something is wrong and enables us to seek help when needed.