Every Designer Needs to Know: Memory Imperfect and Individual Difference
Have you ever suffered from forgetting a new password that you just created? Have you ever feel a new web/mobile app is so easy to use even though you are the first-time interact with it? Everyone is more or less suffering from memory failure daily. As a designer, we need to understand how human memory works and how’s the design can support users’ forgetting curve and learning curve.
People Have Limited Memory
We have to confess that our memory is imperfect. Just as the human visual system has strengths and weaknesses, so do human memory and attention.
Our memory is consist of two types:
Working memory (sometimes termed short-term memory), which is relatively transient and limited to holding a small amount of information.
Long-term memory, which involves the storage of information after it is no longer active in working memory and the retrieval of the information at a later point in time.
We often say working memory is the temporary holding of information that is active, either perceived from the environment or retrieved from long-term memory. While, long-term memory involves the relatively passive store of information, which is active only when it is needed
Working memory is low capacity and volatile. George Miller, the cognitive psychologist, in 1956 has proposed in the book of the magical number seven, plus or minus two mentioned that the number of objects an average human can hold in short-term memory is 7 ± 2.
If the design require working memory for more than 3 items for more than 7 seconds or 1 item for more than 70 seconds will invite errors. Information in our working memory can easily be lost.
If items in working memory don’t get combined or rehearsed, they are at risk of having the focus shifted away from them. Losing items from working memory can correspond to forgetting. For example, you may go to another room for something, but cone you’re there you cannot remember why you came.
Long-term memory has many weaknesses and is unreliable. Long term memory is different from working memory. Our long-term memory is stored in a distributed fashion, spread among many parts of the brain. Information stored in long-term memory doesn’t disappear, but it does lose strength. (Johnson, 2014| more details please reference this book.)
- Error-prone. Since our memory is encoded by networks of neurons acting together and the large numbers of neurons allows for a great many different combinations of them, our long-term memory can ben combined into several version, which causes our long-term memory is not accurate, high-resolution recording or our experience. We can use the heavy compression methods that drop a great deal of information, such as Images, concepts, events, sensations, actions, to help us reduce to combinations of abstract features.
- Weighted by emotion. Have you ever seeing a cat in front of the yard, you recalled a memory that you raised a similar cat in your childhood? Humans, especially adults could easily have strong memories emotionally attach to an object. When you see that object, you would be likely to recall the event and memory with it.
- Retroactively alterable. Some details in long-term memory may be dropped when you retrieving it because the details do not fit your common concept.
Factors of Influence Memory Performance
Understand the characteristics of memory, both working memory, and long-term memory can help designers understand how to implications of memory for user interface design.
Factors that can affect our working memory performance including:
- Numbers of items. If you have tons of items to remember, you will likely struggle to remember them, unless you will have a high strategy guiding you and helping you consolidate and free up space in working memory. The consolidated can be done through chunking. Our brain can organize the information to sets of chunks. Chunking is the center of reducing the number of items in working memory, which can increase our capacity for working memory.
- Similarity/confusability. When the items are familiar, we can easily chunk similar items together.
- Repetition. Repetition can lead to faulty recall in working memory. For example, when you remember a number 5774, you may likely to remember it as 5744.
On the other hand, if we repetitively rehearsal the information in our working memory, the information can be more likely to form into long-term memory, which we can retrieve it whenever we need it. Also, When we build repetition for a thing, we are more likely to build this thing into a habit.
- Interruption. Interruption can make our working memory more difficult to remembering information, especially when our attention is disrupted while it is working with information.
Factors that affect long-term memory retrieval including:
- Strength of the items in long-term memory. The strength determined by frequency and recency of use. Frequency refers to how often the information you use or retrieve the information from long-term memory. Recency refers to how long ago you retrieve the information from long-term memory.
- Associations between items and other stuff in the long-term memory. when there’re a number of different associations for this information, the more likely we can retrieval the information.
- When we build through repetition in a consistent context over time, we more likely to transfer the memory into habituation. Habituation can build through repetition and consistent performing in a context over time with embedded rewards.
The Methods of Supporting Memory in User Interface Design
Since we’ve already known our working memory is low capacity and volatile and our long-term memory has many weaknesses and is unreliable in early. As a designer, we should help users remember essential information from one moment to the next. Don’t require them to remember system status or what they have done. The practical methods we can use to help users reduce working memory load are(Lee, Wickens, Liu, Boyle, 2017 | more details please reference this book):
- Minimize the working memory load. In general, designers should try to avoid long code of arbitrary digits or number strings. If there’s any technique can offload information in working memory sooner, the design is more valuable. For example, in search results, when a user enters a search term and results appear, a person’s attention naturally would turn away from what he/she entered and toward the results. therefore, you should be no surprise that people viewing search results often do not remember the search terms they just typed. Thus, in the search results design, providing the search filed and search term users just entered to reducing the burden on the user’s working memory.
- Provide visual echoes. This refers to whether the visual material can be easily rescanned. When providing the auditory materials, we need also to provide visual echo with to convey its message, because visual material can be easily rescanned. However, auditorial materials cannot be reviewed.
- Provide placeholders for sequential tasks. It means that if a task that requires multiples steps, designers should provide some visual reminder of what steps have been completed. Any action may be that is similar in appearance or feedback would benefit from some visual reminders.
- The superiority of letters over numbers. people usually have a better memory than numbers. For example, instead of designing your business phone number as 467–968–2378, design it like 467-YOU-BEST.
- Minimize confusability in working memory. we can provide spatial separation to reduce confusability. For example, when we designing an interface, spatially separate each different sections instead of a single display, because spatial location represents a salient, which discriminates cue to reduce item confusability.
- Avoid negative instruction. We ensure to provide positive instruction instead of negation instruction in design, because negation imposes an added chuck in working memory, even if it is perceived in reading. Users are more easily forget negation instruction than positive ones.
In order to make sure design support long-term memory, at the very least, designers should avoid developing systems that burden long-term memory. Designers can take the following methods(Lee, Wickens, Liu, Boyle, 2017 | More details please reference this book). Yet that is exactly what many interactive systems do.
- Encourage users to regular use of information. The frequency of use can increase the strength of long-term memory
- Standardize the design pattern. Since standardization enables people to develop stronger schema and mental models. If the controls, displays, symbols, and operating procedures can standardize in some way, it is more likely to recall the long-term memory from a user.
- Provide computer-based or hardcopy memory aids. For example, we can design a context of command languages and menu. Provide contact customer support/retrieval password support to recover passwords when users cannot recall.
- Design helpful habits. When we designing a display, considering its context, repetition of functions, and rewards users to reinforce desired behaviors and discourage bad habits.
- Support the correct mental model. We can provide the concept of visibility and transparency for some functionality in design to support users’ mental models.
- Provide consistent operation in the system and with other applications. The more consistent the operation of different functions, or the more consistent the actions on different types of objects, the fewer users have to learn. User interfaces that have many exceptions and little consistency from one function or object to another require users to store in their long-term memory many features about each function or object and its correct usage context. The need to encode more features makes such user interfaces harder to learn. (Johnson, 2014| more details please reference this book.)
John D Lee, Christopher D. Wickens, Yili Liu, Linda Ng Boyle (2017). Designing for People: An Introduction to Human Factors Engineering 3rd Edition
Johnson, Jeff. (2014). Designing with the Mind in Mind: Simple Guide to Understanding User Interface Design Guidelines