Inside the User's Mind, the Iceberg of Cognition — Selective Attention, Chunking, and Mental Models
User experience is ultimately completed inside the user's mind. Using the iceberg as a metaphor for cognition, we examine three cognitive processes at work beneath the surface: Selective Attention, Chunking, and Mental Model.
Cognition refers to the overall mental process by which we take in and process external stimuli and information. It is not confined to mere sensory perception — seeing with the eyes, hearing with the ears — but encompasses the entire sequence of interpreting, categorizing, remembering, and later retrieving and using the stimuli we have taken in.
When we encounter an object or environment in the world, we gather information through every sensory representation we can perceive from it. Some of this we unconsciously filter out, while some we selectively accept and construct into meaning of our own. What matters here is that the sum of the meaning formed this way about a given object becomes, in itself, the user experience of that object. This is precisely why people using the very same product can end up with different experiences, and why understanding cognition in the field of UX design is not mere background knowledge but a fundamental starting point for design itself.
The Iceberg of Cognition
Human cognition is often compared to an iceberg.
It’s a well-worn metaphor, but whenever something enormous lies hidden beneath the surface, we like to call it “the tip of the iceberg.” The same holds true for human cognition, and this iceberg metaphor offers a genuinely useful frame for understanding its nature. Just as the portion of an iceberg that rises above the water is only a small fraction of the whole, the visible realm of conscious awareness occupies a smaller share of cognition overall than we tend to assume. It is the subconscious hidden beneath the surface that is far larger and more extensive, and it exerts a profound influence on our judgments and reactions.
And just as observing only the iceberg above the waterline makes it hard to gauge precisely what lies beneath, observing only a user’s conscious responses makes it difficult to grasp the subconscious mechanisms operating behind them — which is exactly why this metaphor captures the nature of cognition so well.
Taking the analogy further: just as the Titanic met disaster by colliding with the hidden mass beneath the water’s surface, user experience, too, can run into unexpected consequences by colliding with subconscious cognitive patterns that the designer failed to grasp. A design that appears, on its face, to have no problems at all can still cause users discomfort or confusion — and this is precisely the context in which that happens.
This is why, just as navigators use sonar and underwater surveys to map the hidden face of an iceberg, UX designers, too, need to make the effort to understand the full shape of this iceberg of cognition. Through user research, behavioral analysis, psychological theory, and other means, we need to study what cognitive processes shape the experience of our target users, and at which point in that process — and in what way — we should intervene and adjust it to create a better experience.
Of course, diving deep into the full depths of cognitive engineering would be an overwhelming and difficult undertaking, but that is no reason to give up on understanding cognition altogether. Let’s begin, then, by looking at a few of its core mechanisms.
Three Cognitive Processes That Shape Experience
If we view the process as a cycle — an external object is perceived through the sense organs, that perception is stored as memory, and that memory in turn shapes how new information is processed — three major cognitive processes stand out within this cycle: Selective Attention, Chunking, and Mental Model.
Each of these three plays a central role at a different stage: one at the gateway where information enters, one in the process of organizing that information, and one in the stage of interpreting and putting that information to use. Let’s look at each in turn.
Selective Attention
The first gateway of cognition is Selective Attention. Unlike a camera or a recorder, we cannot take in every last piece of information that reaches our sense organs.
In reality, even a camera or a recorder registers different amounts of information at the center of the frame versus the periphery. But this is simply a physical limitation caused by distance, whereas human selective attention goes further than the physical realm, actively discarding information that is deemed cognitively unnecessary.
Because our cognitive resources are limited, when we focus attention on a particular area, we take in the densest information from that area, while our receptivity to information outside that area of focus drops off sharply. It’s much like shining a flashlight into a dark room: whatever the light touches is seen clearly, while everything else remains in darkness.
Various factors drive what we choose to focus on — our own preferences and interests, the level of risk or urgency carried by the information itself, and the visual contrast it has against surrounding information, among others. In general, the higher an element’s visibility, the more likely it is to be selected for attention, though this is not always the case. Because this selection is deeply shaped by the memories and experiences a person already carries, even when looking at the very same screen, users can differ considerably in where their attention lands and what they notice first.
Chunking
Information that has made it through the filter of selective attention isn’t home free yet. At the next stage, our cognition performs another crucial operation: grouping the information we’ve received by meaning, so as to reduce the number of items we have to process.
One well-known “law” related to this is the Magic Number 7 — the idea that the amount of information a person can process in short-term memory is around seven, or seven plus or minus two. Follow-up research has raised plenty of disagreement about the exact figure, with some arguing the real number is even smaller, but what truly matters here isn’t the specific number — it’s the underlying fact that human short-term information processing has a clear limit.
And the strategy our cognition naturally uses to work around this limit is Chunking. Taking in and processing a set of unrelated, individual pieces of information one by one demands an enormous cognitive workload — or may be impossible altogether — but when information that is meaningfully related is grouped into a single chunk, the cognitive load drops sharply, and as a result we become able to process a far larger volume of information efficiently.
Mental Model
If chunking is the process of efficiently grouping incoming information, a Mental Model goes a step further: it organizes that information into a coherent, systematic structure. Drawing on accumulated memory and experience, we build structures of information about particular objects or situations, and when we later encounter new information, we use these structures as a frame through which to receive and interpret it.
Take, for example, the object we call a camera lens — each of us carries our own structure of information about it. Someone with little experience with cameras might have a structure that goes no further than “round in shape” and “the basic function of projecting an image.” Someone who has spent years taking photographs, on the other hand, will have a far richer structure that includes the workings of the aperture, its relationship to shutter speed, the effects of various filters, and other fine-grained details.
The same is true for something like a gun. One person’s structure might contain only basic elements like the trigger and the grip, while someone with more experience might have it systematically organized down to details like the sights, the safety, and the magazine.
Now imagine someone who holds their own structure of information about both lenses and guns encountering an unfamiliar object that seems to combine the shapes of the two. What happens? Even though it’s an object they’ve never seen or used before, their existing structures for lenses and for guns activate automatically, and they can gauge with surprising accuracy how the strange object works and what it does. They will likely connect the trigger-pulling motion suggested by the gun-like shape with the photo-taking function suggested by the lens-like shape, and expect that pulling the trigger will take a picture of whatever it’s aimed at.
The reason such an inference is possible for an object never encountered before is that our cognition actively draws on structures of information built from past experience. That structure of information is precisely what we call a Mental Model.
The next post looks at what concrete implications these three cognitive processes — Selective Attention, Chunking, and Mental Model — have for actual design, and explores affordance, a concept closely tied to the Mental Model.