Autobiographical and flashbulb memories are subject to change, but other kinds of memories resist change if they’re repeated enough.
Semantic memory is memory of facts. “Is Paris the capital of France?” is a question that uses semantic memory. So is “What is 9 x 6?” Once semantic memory is set, it’s not subject to as many changes as autobiographical or flashbulb memories. The tricky thing about semantic memory is not retrieving it once it’s set, but getting it to set—the psychologist’s term is “encode.” While people are learning these facts, they’re subject to change and retrieval errors because the neuron firing traces aren’t very strong. But when they repeat the fact over and over, the neuron trace gets stronger and is less likely to change. It’s possible to make someone believe (incorrectly) that Lyon is the capital of France, but you’d have to repeat that a lot for it to begin to replace Paris in memory once she’s learned Paris.
Learning Motor Skills
Another type of memory that stays constant is called procedural or muscle memory. When you learn how to drive a car, ride a bike, or type on a keyboard, you’re using muscle memory. This type of memory also requires a lot of repetition to be set, but once set, it’s hard to change or forget. Once you learn to ride a bicycle, you’ll be able to ride a bicycle forever, even if you don’t ride one for a while. If you haven’t been on a bike for 20 years, the first minute or two might be a little rocky, but then the muscle memory for this skill is activated and the memory returns intact. This is why it’s so important to learn a motor task correctly the first time. If someone learns to use two fingers to type on a keyboard rather than using the standard two hands on the home row, it will be hard for her to unlearn that and learn how to type keeping all her fingers on the home row.
Memories of senses—vision, touch, hearing, smell, and taste—are stored for different amounts of time. As you’re reading this book, your visual sensory memory (iconic memory) is activated for a few seconds. Your brain is remembering the letters you’re seeing just long enough to string a few words together. Your brain remembers the sounds you hear (echoic memory) long enough to make sense of a particular sentence. The same is true of touch, but taste and smell are different. When you smell something (olfactory sense) and taste something (since smell is so active in taste), the sense impression bypasses most of the higher brain, where vision and sound are processed, and goes straight to the amygdala, where emotions are processed. Smell and taste memories are not easily changed. And because the amygdala is involved, a smell or taste may elicit a strong emotional reaction and a memory.
Design And Memory
So, what’s the relationship between design and these kinds of memory?
You may not realize that when people interact with software, an app, a website, or a product, they’re encoding and retrieving semantic, sensory, and muscle memory almost constantly. You think they’re focused on the task that your product allows them to do— paying bills, editing a movie, or using a remote control. And they’d agree with you. They think they’re doing tasks with the product, too. Of course they are, but in the background, much of what they’re really doing is retrieving semantic, muscle, and sensory memories. If you’re designing anything for people to use, then you’re actually designing the retrieval of memory traces.
Because I use my smartphone a lot and because I can set it up the way I want it, I have semantic, sensory, and muscle memory of how to look at the weather forecast, check my email, or play my favorite music.
When I wake up in the morning, I reach for my phone. I’m not even out of bed. I’m not even awake. I grab the phone, click the button that brings the screen to life, and touch the icon for messages. I use:
- Touch sensory memory combined with muscle memory to know that I have to physically click the oval button on the side of the phone (not just touch it) and to know where it’s located. I can find that button without vision.
- Semantic memory to remember what I usually check (weather, texts, calendar).
- Visual sensory memory to move to the part of the screen where I know certain icons will be and to recognize the icons, and muscle memory to start moving my finger or thumb to the place on the screen even while my visual sensory memory is remembering where to go.
- Echoic sensory memory to respond in a certain way when I hear an audio alert, ping, bell, or chime.
And so on.
Let’s look at an online banking app. I use a banking app from a large US financial organization. Seventy percent of the time I use it to deposit a check, 20 percent of the time I use it to transfer money from one account to another, and 10 percent of the time I’m checking balances. Yet when I log on to the banking app from my phone, depositing a check and transferring money are hidden in the Menu icon. And the Menu icon moves. Sometimes it’s at the top and sometimes it’s at the bottom; sometimes it’s on the left and sometimes on the right. This means I have to use my semantic memory to remember that these functions are hidden in the menu, and then my sensory and muscle memory to get there.
The same is true of desktop applications. If I’m editing a video, I have a lot of semantic memory demands. For example, transitions between frames are categorized as wipes, movements, or blurs. The transition I like to use is stored in semantic memory. My muscle memory helps me scroll to the part of the timeline I want and, as I get more adept, muscle memory lets me use the mouse to move sliders. Sensory memory helps me identify whether what I’m looking at on the screen is a project or library (based on the icon).
When you design, if you know what people want to do the most, then you can design the product to make those things easy to encode and retrieve with these types of memories. You can put things in the same place, use icons that are familiar and standard, and use semantic cues that people have seen before.
You may have heard that you should play brain games to improve your memory. Kirk Ericsson (2014) showed that getting physical exercise does more for your memory than brain games.
- Decide what tasks are the most frequent and important that people will be doing with your product. Then base your design decisions about icons, buttons, naming, categorization, and location on these frequent and important actions.
- Be as consistent as possible with design decisions. When there are industry standards for buttons, links, naming conventions, or icons, use them. It’s one less thing your audience has to encode.