“Human Factors” are design principles devoted to understanding and applying how humans interact with products or processes. There are universal human factors that help guide good design, such as:
- Sensory Perception
- Pre-attentive Processing
- Integration of Prior Knowledge
- Working Memory (topic of today’s blog)
…but the whole point of user experience is to take the burden off the user. Design for simplicity and efficiency and your users will thank you for it.
A critical part of our brain operations is referred to as working memory, which is where information can be temporarily stored or manipulated. Working memory is comprised of the central executive system, which controls the two slave systems: the phonological loop and the visuospatial sketchpad. These slave systems have limited capacity, both in how much information and how long it can be held. For example, you meet someone new and stick out your hand. They tell you their name is “Sarah” and you say, “How are you?” and carry on with a conversation. When your husband comes up, and you go to introduce your new friend, you have already forgotten her name.
Decay is rapid in working memory – without rehearsal, you will lose information within about two seconds.
The phonological loop is where we rehearse and manipulate verbal/acoustic information. When you need to find a number online and then call it, you will rehearse the phone number in your head in order to remember it for that short time in between the search and dialing it on your phone. We typically cap out around 7 items, but chunking meaningful parts together helps to keep information in our working memory. For example, if the phone number ends in the year you were born, you can remember it as a chunk of information, rather than four random digits.
The visuospatial sketchpad is the part of working memory that plays a crucial role in solving visuospatial problems and orienting oneself within space. This is also the area that works with motor (intentional movements both gross and fine), tactile (sense of touch), and haptic (perception of touch) information.
Both the phonological loop and the visuospatial sketchpad are controlled by the central executive system (CES), which determines how to shift or divide attention. If you take Cedar street home everyday, and you’re driving along, listening to music, you need your CES to override the habit of driving home and remind you to stop at the grocery store along the way.
The elderly population, people with specific health issues, and those with limited cognitive abilities have all demonstrated deficits in working memory. The elderly population tends to have limited control over their working memory, so their CES what suffers the most with old age.
Designing for these populations requires careful attention to their working memory limitations. Working memory deficits will affect their ability to process and learn new information. When someone is required to take information from one tab/screen to another, like a temporary password or coupon code, people with limited capacity may not be able to temporarily store as many random letters/digits. Of course we can copy and paste, but the whole point of user experience is to take the burden off the user. Design for simplicity and efficiency and your users will thank you for it.
Recently, I was shopping at Sephora for a new fragrance. They have a quiz available in the store called “Fragrance IQ.” The particular store I visited placed the computer quiz in the middle of the fragrance section, between the E’s and the F’s. Additionally, the A’s started at the back of the store, which is counterintuitive to me. After you take the quiz about your scent preferences and your personality, you are provided with a list of recommended fragrances, which you can sort by best sellers, new items, etc.
I was given a lot of options to choose from, and then I had to go seek these fragrances while trying to remember as many names as I could. Luckily, the store was not that busy, so I kept my options on the screen while I walked around the store. I tried to remember the scents in my working memory, while also orienting myself along the alphabet to find a particular fragrance and then subsequently smell each one.
Even with rehearsal, I found that I could not remember more than three scent names at a time, because they each have a designer, i.e. “Marc Jacobs,” and the name of the fragrance, such as “Daisy”. To complicate the process, Marc Jacobs has about five different “Daisy” scents, so I also had to remember the color and look of the bottle.
This task was too demanding on my working memory, using all parts of the system to store verbal information, visual information, orient myself along the alphabetical set-up, and do this all while trying each scent and determining my opinion of each.
In order to improve their user experience, Sephora should set up the quiz at the beginning of the fragrances, with the A’s in the front of the store, moving along the alphabet as you move towards the back of the store. This would allow less resources wasting on just orienting yourself in the space. The quiz should have multiple options for saving your fragrance choices, such as email, a printed receipt, and an audio option for accessibility purposes – blind people need to smell good too!
The “Fragrance IQ” quiz is only available at the store, so they should expand this to their website and an app, where a person can have the list and pictures right on their phone. Lastly, there is typically limited phone/internet service in shopping malls, where Sephora tends to open up shops. Therefore, making public wi-fi available in store for use of the app and email while shopping would improve their user experience.
The case above clearly demonstrates a need to consider working memory capacity when designing for a positive user experience. This means understanding your average user and other users that may have limited working memory capacity. People of all intellectual abilities should have access and ability to use products designed for the public.
For more information, see links below:
Baddeley, A. D., & Hitch, G. (1974). Working memory. Psychology of learning and motivation, 8, 47-89.
Baddeley, A. D. (2002). Is working memory still working?. European psychologist, 7(2), 85-97.
Barrouillet, P., Bernardin, S., & Camos, V. (2004). Time constraints and resource sharing in adults’ working memory spans. Journal of Experimental Psychology: General, 133(1), 83
Cowan, N. (2010). The magical mystery four how is working memory capacity limited, and why?. Current Directions in Psychological Science, 19(1), 51-57.
D’Esposito, M., Detre, J. A., Alsop, D. C., Shin, R. K., Atlas, S., & Grossman, M. (1995). The neural basis of the central executive system of working memory. Nature, 378(6554), 279-281.
Henry, L. A. (2001). How does the severity of a learning disability affect working memory performance?. Memory, 9(4-6), 233-247.
Linden, M., Brédart, S., & Beerten, A. (1994). Age‐related differences in updating working memory. British Journal of Psychology, 85(1), 145-152.
Schuchardt, K., Gebhardt, M., & Mäehler, C. (2010). Working memory functions in children with different degrees of intellectual disability. Journal of Intellectual Disability Research, 54(4), 346-353.