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Cognition, Chunking, and Design

By Kirk St.Amant | STC Fellow

This column examines how cognitive factors can affect technical communication and design processes. Email the editor at stamantk@ecu.edu.

Our brain is an amazing computer. Like all computers, our brains also have limitations affecting how much data they can process at once. This factor is called cognitive load, and it has implications for usability and design.

Memory and Capacity

Short-term memory is central to cognitive load. When processing input, our minds hold new information in short-term memory to:

  • Identify it (for example, this is a can opener)
  • Determine what to do with it (use to open cans)

If we limit the information held in short-term memory, we can efficiently identify and use items.

There is one problem: our short-term memory can only hold a limited amount of input (7 +/- 2 units of information) at one time. Yet, we continually take in massive amounts of data; why are we not overloading our minds? The answer involves how we combine smaller bits of information into larger units—or “chunks”—for processing.

Chunking and Processing

When you look at a keyboard, you don’t view it as individual keys, letters, and the housing holding the keys together. Rather, your mind perceives all these items as combined into one “chunk,” or unit, for processing—“a keyboard.” This chunking approach limits the overall units of information we need to hold in short-term memory at any time and allows us to process relatively effectively through most day-to-day situations.

This chunking of information is also scalable. It can occur with small items—such as viewing keys and housing as a single keyboard. It also can be extended to how we perceive overall contexts—such as viewing the keyboard as an element in the overall informational chunk associated with “office.” What we focus on when chunking information depends on our objective (e.g., “use the keyboard to…” vs. “go to the office to…”) and on our prior experiences.

Exposure and Expectations

How we organize sensory input is not random. Rather, our experiences teach us to chunk smaller components into larger, comprehensive units of information. The more we encounter a keyboard as a collection of keys housed in a container, the more we learn to combine those elements into one unit for processing. The more we encounter keyboards in office spaces, the more keyboards become part of the chunk we associate with “office.” Over time, these experiences shape how our minds identify input to readily organize sensory data into well-established units for consideration. They are also central to how we can pack large amounts of information into our short-term memories for quick and effective processing.

This is why we often feel overwhelmed in new situations. When we have no pre-existing model for chunking sensory input, we need to review the individual items we encounter to determine what they are and how they work together to achieve objectives. Doing so quickly fills short-term memory and can result in feelings of information overload—too much information to process at one time. Cues that help us chunk the data we encounter, however, can help us better navigate new contexts and use the materials in them. It is this relationship that is key to usability and design.

Design and Usability

Making new information usable involves helping individuals organize it into identifiable units. Strategies to for achieving this objective include the following.

Parallel chunking: This approach involves using prior experiences to guide the chunking of new information. If we design new items to resemble existing ones, we can help users organize sensory information quickly and more readily recognize and use things. This is because our minds can use existing frameworks to organize new input into chunks. An example is designing the toolbar of a new word processing program to resemble that of existing programs to help users identify and use features instead of struggling to make sense of a completely new design.

Identifiable chunking: This strategy relates to designing a completely new item. In this case, individuals cannot replicate an existing design. Rather, they need to create something completely new. In such situations, usability involves designing in a way that chunks new information into a limited number of easy-to-identify units. This can be done by:

  • Restricting the distinct features of the design (e.g., seven or fewer menu options on an interface).
  • Labeling each feature accordingly (e.g., using “Italicize Text” to note this specific font feature).

In these instances, the key to usability is to avoid assuming new items inherently indicate what they are and what they do. Rather, a product developer must account for both when creating new designs (for example, use both text and images to identify different software features or functions). Doing so provides the user with a ready-made system for chunking new information into units that short-term memory can easily identify and process.

Final Thoughts

Usability is often a matter of how our minds perceive and process information. By understanding how short-term memory works, we can create materials that are easier to use. Designs that chunk information effectively can contribute to the usability of materials. Technical communicators can use certain strategies to apply these ideas in ways that make meaningful contributions throughout the product design and development processes.

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