Designing for the age-enhanced: cognitive changes

If you’ve read the previous posts in this series, you understand the changes that happen to our vision and hearing as we age and, more importantly, how those changes affect our interactions with the products we use. For this article, I want to look at the impact that aging has on some of our basic cognitive abilities and, of course, what those changes mean for design.

It’s a sit-com staple that we mentally “slip” as we age; older characters ramble on about the past, but can’t remember where they parked their car; they can’t figure out new technology (done to hilarious effect in the first episode of The Millers); they…well, you get the idea. But most of us can point to relatives who were sharp at advanced age – my 92 year-old grandmother easily stomps my mom in pinochle and my husband’s 90 year-old grandmother lives very well on her own.

Why the discrepancy? Just as changes in vision and hearing vary widely, so do changes in cognitive capacities. Some of us, like my grandma, will experience very little decline even late in life, while others may (unfortunately) experience problems starting much earlier. However, we generally do slow down mentally as we get older (even ignoring the effects of dementia and Alzheimer’s, neither of which are part of normal aging). This is particularly true for attention and memory – two fundamental cognitive functions.

First, let’s fully define the problem age-enhanced users face. Then, I’ll outline how to begin solving that problem.

Let’s start with attention. Simply put, attention is your ability to focus on something while ignoring distractions. Psychologists (like yours truly) talk about attention in a lot of different ways – overt versus covert, visual versus auditory, bottom-up versus top-down, and many more – but for this article, we’re going to stick with the basics: selective attention versus divided attention.

Selective attention is what most people think of as “attention.” It’s the ability to focus on something while disregarding things that are irrelevant to whatever it is you’re trying to do. For example, while reading a book on the couch next to your spouse who’s watching TV, can you tune out the TV to focus on the book? Divided attention, on the other hand – what we often call “multitasking” – is the ability to divide your attention between several different tasks simultaneously or rapidly switching between tasks. How effectively can you read that book AND watch the TV show? Can you interrupt reading a report to check your email and then go back to the report again without losing any headway?

Studies have demonstrated that divided attention, in particular, declines with age. An older person performing multiple tasks at the same time, or switching between tasks, tends to perform worse on one or both tasks when compared to a younger person. [1] This appears to be because it takes longer for the older person to reorient when switching tasks. [2,3] Similarly, older adults perform well on selective attention tasks when there are no distractions. However, when distractions are present (particularly visual distractions), the performance of older adults drops significantly more than does that of younger adults.

These decrements can be particularly noticeable when you consider a task like driving. Driving requires switching attention between driving the vehicle, being aware of the environment, interacting with other people that may be in the car, and a host of other things. Problems with attention have been shown to be highly associated with the higher number of accidents experienced by older adults. [4, 5]

Like attention, memory isn’t a single thing either. We usually talk about memory as consisting of short term and long term. Short term memory (STM) is our ability to keep things in our active, conscious thoughts – like remembering the next couple of steps in a recipe that you’ve just read. Coupled with STM is working memory, our ability to manipulate information held in short term memory (like mentally doubling ingredient quantities to double the recipe). Older adults are very capable of keeping information in STM, but performance drops once a task requires working memory to transform what they are holding in STM. [6, 7]

Long term memory (LTM) is information we’ve stored permanently (more or less) in our minds that can be recalled at will (more or less). But LTM is also an umbrella term; there are several types and each can be differently affected by aging. Actually, research results for the effects of aging on LTM often conflict, because small differences in the research controls, variables, and methods can create differential effects. In general, research tends to agree that semantic memory, or general knowledge acquired about the world, such as who was the first President of the United States and who is the current President, shows very little decline with aging.[8] Similarly, autobiographical memories, or memories that you have about yourself, show very few age-related declines.[9] But procedural memory, your ability to perform learned tasks, like typing, tying your shoes, or knitting, is impacted by aging. Tasks that are already learned don’t show a decrement, but older adults often have difficulty learning new skills, particularly complex skills. Finally, episodic memory, memories about personal events regarding certain times and places (like what you had for dinner last Tuesday), and prospective memory, your ability to remember to do something in the future without external memory cue (like attending a doctor’s appointment or taking medication), both tend to show significant declines with age.[10,11]

So what does all of this mean when designing products, particularly interfaces, for older adults? How do we approach a design to ensure that older populations can effectively use it?

  • Draw the user’s attention to task-related information. This is obviously a recommendation that applies to all age groups, but in particular, will significantly impact whether an older user will be able to use your product. Information that is important for the task at hand should be emphasized, which includes any instructions that the user must follow and any displays that provide a result. With limited ability to acquire new procedural memories, the older user will be relying on those instructions each and every time he or she uses a product, much more so than will a younger user.
  • Do not draw the user’s attention away from task-related information. Given the reduced ability of older users to reorient once distracted and their reduced ability to ignore distractions, any potentially distracting elements that are not directly related to the task at hand – like entertaining animations or blinking decorative elements – should be removed. While these might enhance the user experience for a younger user, they will be very disruptive for the older user.
  • Minimize the need for the user to divide attention. Do not require the older user to carry out more than one task at a time. Even switching between an instruction manual and the product may cause disruptions in the older user’s ability to concentrate on the task at hand. So design your system with all needed information available. For example, don’t use error codes that the user must look up. If there is a problem, directly say what the problem is and how to fix it.
  • Make the product as intuitive as possible for the age group / minimize the need for new skills. Again, this recommendation applies to all age groups. However, what is intuitive for an older user may not be the same as for a younger user. Products designed for older populations will be easier to learn when the operation is similar to other products that they routinely use. The latest and greatest touch conventions, while very intuitive for younger users, could very well be incomprehensible to the older user.
  • Perform any and all calculations for the user and limit the need for short term memory. Do not expect the older user to be able to manipulate information mentally. For example, a glucometer for an older adult should tell the user how much insulin is required to correct a high blood sugar, rather than expect the user to make that determination. Again, this recommendation benefits all age groups, but when designed contrary to this, older users will be more likely to fail.
  • Provide context for the user. If a product requires many steps, provide information that allows the user to know where they are in the process, including the immediate goal. This further limits the need for short term memory and provides memory cues to complete the overall procedure.
  • Do not expect the user to remember to do something in the future. If the user needs to take a step in the future – such as checking blood sugar levels after treating a low or high blood sugar event, provide reminders at the appropriate times.

So, you can see that aging and its effects on our cognitive abilities and senses have profound implications for product and interface design, not just in the way that information is seen or heard, but also in the way that the information must be structured. But we’re not done yet. Check back in the future to learn about how aging affects our senses of touch and proprioception (our sense of how we move and orient our bodies).

Carolynn Johnson


References:
1 Wright RE. Aging, divided attention, and processing capacity. J Gerontology, 36:605–614, 1981.
2 Verhaeghen P, Cerella J. Aging, executive control, and attention: a review of meta-analyses. Neurosci Behav Rev. 2002;26:849.
3 Kausler D. Psychology and human aging. 2nd ed. New York (NY): Springer-Verlag, 1991.
4 McDowd JM, Shaw RJ. Attention and aging: a functional perspective. In: Craik FIM, Salthouse TA, editors. The Handbook of Aging and Cognition. 2. Erlbaum; Mahwah, NJ: 2000. p. 221., Park DC.
5 Gutchess AH. Cognitive aging and everyday life. In: Park D, Schwarz N, editors. Cognitive Aging: A Primer. Psychology Press; Philadelphia, PA: 2000. p. 217.
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8 Salthouse, 1982, The Processing-Speed Theory of Adult Age Differences in Cognition, Psychological Review 1996, Vol. 103, No. 3.403-428.
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10 Nilsson LG (2003). Memory function in normal aging. Acta Neurol. Scand., Suppl. 179: 7–13.
11 Einstein, G.O., & McDaniel, M.A. (1990). Normal aging and prospective memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16, 717–726.