December 2018
Text by Kirk St.Amant

Image: © sturti/

Kirk St.Amant is a Professor and Eunice C. Williamson Endowed Chair in Technical Communication at Louisiana Tech University (USA) where he is also a Research Faculty member with Tech’s Center for Biomedical Engineering and Rehabilitation Science (CBERS). He researches how cognition affects usability and the design of technology with a focus on international health and medical contexts and international online education.


Usable design – giving users what they expect

Usability is determined by how quickly our users can identify a certain function of our product and use it – a process strongly linked to our users’ experiences and expectations. Here is how understanding cognitive processing can lead to better, more usable designs.

Nothing is inherently usable. Rather, usability reflects how our minds process sensory input to identify and categorize objects. If we understand such processes, we can create materials that match them and develop more usable designs. Doing so involves learning how the brain organizes information and designing materials that address these processes. 


Cognition and data processing 

Cognition describes how the mind identifies, organizes, and responds to information. While our brains operate with amazing speed, there are limits on how much information we can process at once. This is often referred to as cognitive load, which is connected to short-term memory. 
When we encounter something, our brains must 

  • Identify what that item is (e.g., a pen)
  • Classify what it does (e.g., allows us to write words on a page)
  • Determine what to do with it in a particular context (e.g., take notes for a business meeting)

This process begins in our short-term memory, where the brain holds initial sensory input to identify and categorize it. Our short-term memories, however, are limited in the amount of information they can hold at one time. This limit is 7 +/- 2 units of information or 5 – 9 units total. How those units are defined depends on the individual’s prior experiences. Understanding how the brain forms such units is central to design and usability. 


Chunking and organizing information 

Our senses continually take in large amounts of information – seemingly more than we can process at one time. This situation creates challenges for our short-term memory and cognitive load. For this reason, our brains need to minimize this data. If they don’t, we experience information overload – the paralysis of encountering too much information at once. To manage input, our brains use a specific strategy. 

We don’t perceive all sensory input as individual items for processing. Rather, our brains combine smaller bits of sensory data into larger units – or "chunks" – of information. This chunking reduces how much information our brains need to process at one time. It is what allows us to engage in a variety of complex tasks without feeling overwhelmed. 

The process works as follows: When we look at a pen, we don’t view it as its separate parts – cylindrical tube that holds ink, tip for writing, clip for attaching it to a pocket, etc. Instead, our minds combine these parts into one unit or chunk of information we process as "pen". This chunked concept of "pen" occupies less mental space and is easier to process than thinking of a "pen" in terms of its individual parts. It allows the brain to manage sensory input.  


Chunking and usability factors 

This chunking of information has important implications for usability. Designs that organize information into a limited number of easily identifiable units allow our minds to process them more easily. Such designs reduce cognitive load and seem easier to understand and use. An interface containing only five distinct elements (five chunks of information), for example, addresses the limitations of how our minds organize information and will be easier to use. Note: This does not mean the interface can only contain five items in total. Rather, it involves having the text, images, and other features on a site organized into five readily identifiable, self-contained elements – such as the number of menu bars, grouping of icons, and separate blocks of text that appear on a site. 

To illustrate this, take a look at Figure 1. The image appears overwhelming. This is because it presents too many separate units of visual information – more than our minds can effectively process at one time.

Figure 1: An example of too much information for our minds to easily process


However, if we use design features to clearly organize that same information into a limited number of units, we can more easily process it, and we feel less overwhelmed, as you can see in Figure 2.

Figure 2: Large amounts of data organized into a limited number of units or chunks

If we provide prompts that help contextualize and clarify the order in which to use data, our ability to process that information increases even further (see Figure 3). Such features help our minds organize the information for processing vs. spending cognitive energy to determine how to assemble the individual parts (the five elements with red borders) into one overall chunk for "interface to use." 

Figure 3: Information organized into units and units organized into steps in one overall process


By limiting the information our minds need to process, we can transform a seemingly overwhelming visual design into something relatively easy to use.  


The role of experience

The brain does not chunk information randomly. It learns how to combine different kinds of information into certain chunks based on our experiences. The more we encounter a pen and observe that it consists of certain parts, the more our minds learn to chunk that information into one unit for processing. In this way, our experiences help our minds develop design expectations. 

This is why we expect items to look a certain way in order to identify them. We expect pens to have a certain shape and have certain features, because our experiences have taught our minds to look for specific input (features we associate with a pen) and chunk this input into a unit for "pen". When we look for a "pen" or we hear the word "pen", our minds expect to encounter this information. If certain features (information) are missing, the brain will have a difficult time determining what the object is. This is because the sensory input the brain encounters does not match existing mental models it uses to identify objects. These experience-based relationships have important implications for design and usability. 


Meeting design expectations

How the brain learns to chunk information helps explain why new designs can confuse users. With no pre-existing model for chunking input, new designs require us to view each element of a design as an individual unit of information for cognitive processing. This situation means our short-term memory needs to hold large amounts of information as we try to determine what this new item is and does. Doing so can lead to feelings of information overload where the design seems overwhelming or too complex to understand. This is because our short-term memory is struggling to accommodate all of the new information it needs to hold for our brains to process.

A similar situation occurs when we encounter revised or modified designs. If the revision of a product involves changing its features, the resulting design could affect how we chunk sensory input. In some cases, a revised design could involve adding, removing, or altering a certain feature. This can affect how our minds match the new design to prior models we used to chunk information in short-term memory. The results are similar to how the mind processes new designs: It views the item in terms of all of its different parts as it tries to chunk those parts into smaller units for cognitive processing. Again, this situation can result in feelings of information overload that could cause confusion or frustration. 

To consider these cognitive factors for better usability, we need to research our users’ expectations for design. The key is to categorize how individuals process sensory input when they identify items. If we can determine such factors, we can create designs that match the cognitive structures individuals associate with certain objects. The aim is to create a map of how users organize information and to use this map to guide the design process. 


Mapping and cognitive expectations

Designing effective materials involves understanding how users chunk information to identify objects. Gaining such an understanding requires us to identify the design elements users expect when they encounter an object. In other words: What features make a "pen" a "pen"? The aim is to determine the features users associate with a certain thing. These are the features users expect to encounter when identifying objects. 


Collecting data 

Interviews or focus groups are an effective way to collect such design data from an intended audience. The goal is to "map out" or list the features that users associate with an item. This can involve 

  • Verbal mapping – asking the user what an item should look like, e.g. "Tell me what an email login screen looks like."
  • Visual mapping – asking the user to draw an example of what the item should look like, e.g. "Can you draw an email login screen for me?"

In each case, the user notes the features he or she combines to create the cognitive chunk used to identify an object – in this case, what features he or she expects from an email login screen. This process isolates the specific features individuals actually use to identify an object vs. all of the possible features that the object could have. 

Equally important is the placement of key elements within the item, for such placement represents how users organize the data into a recognizable chunk. So, as users note the features they associate with an item, they also need to explain where each feature is located on the object. This could involve asking questions such as, "You said an email login screen should have a prompt for 'username'. Where on the email login screen does the username prompt appear?" This approach helps determine how individuals expect such features to be organized according to the way their brains chunk information. This process allows us to create a map of 

  • what information needs to be present in a design, and
  • how the information needs to be organized in a design 
  • so users can recognize and use items more easily. 

Developing designs

We then need to compare responses from multiple users to determine what features seem most common. These common features establish the foundation – or prototype – for what these users expect to encounter on a particular object. We can use this prototype information to create an example object/design and test it with our audience. This testing involves users commenting on how well a prototype meets their design expectations. 
In testing prototypes, we should ask users to:

  • Identify the object ("What is this item?")
  • Note factors contributing to this process ("How do you know it is an email login screen?")
  • Mention needed revisions ("How would we need to revise this item so you would recognize it as an email login interface?")

Other important questions to ask involve the positioning of features to confirm they meet design expectations. Doing so could include questions such as: 

  • "Is this where the ‘username’ prompt should appear on the email login screen?" 
  • "You noted the ‘password’ prompt was in the wrong place. Where should it be located on the email login interface?"

Again, the objective is to identify the features individuals include in the chunk of information used to identify an item. We can use this testing to revise a prototype design to better meet user expectations. We can then retest this revised design to determine how well it meets user expectations. This iterative process can continue until we believe we have created an effective, usable design for the related audience. 


Creating guides 

The objective of this overall process is to create a design map comprising:

  • A checklist of features a group associates with the design of an item
  • A schematic identifying where users expect each feature to appear on the item

We can use this design map for modifying existing designs or designing new items that users can easily identify and use. Such design maps can also help the members of a team focus on common design elements when revising materials or creating new items. This can help avoid confusion or debate over what constitutes the most effective – or usable – design for an audience. 



Usability is a matter of perception. The more readily we know what something is, the more effectively we know how to use it. Such factors are connected to how our brains process information and perceive items. By understanding how cognitive aspects work, we can design materials to meet user expectations and enhance the usability of items.