A Primer on Mental Models

The Why, When, and How for turning UX research into a map of users’ mental spaces

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RE: Write

7 min readFeb 6, 2019

Mental models date back at least a couple of centuries as a psychological concept, but they’ve been adapted by the HCI field as a tool to better understand how people think about doing things. Here’s a roundup of the things I’ve learned about mental models as a UX designer in training — what they are, when to use them, and how to go about making one.

What is a mental model, anyway?

Most simply, a mental model describes the way a person understands how to do something. It’s a map of the mental spaces a person cycles through in order to accomplish a goal.

In a design setting, a mental model can help designers access design challenges from users’ perspectives. It’s laid out in clusters of “tasks” — thoughts, feelings, and the behaviors that arise from them — which are thematically grouped together. The tasks and groups can be mined for opportunities to reduce the cognitive load required for the user to accomplish their goal.

To clarify this definition, it’s helpful to understand what a mental model is and is not: They focus on users’ mental states, not interactions with products. They represent a user group, not a single user. They are cyclical, not linear. They reflect current (as-is) states, not future (ideal) states. They are based in research, not hypothetical.

Let’s break down those 5 defining characteristics and illustrate them with the example goal of buying groceries.

Focus on users’ mental states, not interactions with products.

A mental model describes the thoughts, feelings, and discrete actions associated with various mental states. Indi Young collectively refers to them as tasks. These tasks are generally tool- and product-agnostic. In other words, the mental model stays focused squarely on users’ internal state and how it drives behavior, rather than on how users’ interface with existing solutions.

Represent a user group, not a single user.

A mental model holds true across multiple user journeys. It is an abstraction of a process, a mental template, that can manifest in multiple user stories.

For example, the mental model for grocery shopping might include mental space categories for Plan Meals, Select Items, and Buy Groceries. Here are 2 very different user journeys that still generally comply to this flexible mental model:

A young, urban single might make a mental list while on the subway home from work, stop by the bodega near her apartment, load up a basket with some ingredients for dinner plus some impulse buys, then stuff the haul in her oversized work tote and schlep it all home. She might do that again two days later.

On the other hand, a suburban, stay-at-home mom might plan meals two weeks out, make a list, drive to a big-box store, and overload a cart while corralling her child through the aisles.

Cyclical, not linear.

A mental model is not a story, or a linear journey from point A to point B. Instead, it describes multiple mental spaces that a user might move back and forth between as they complete their goal.

While grocery shopping, a person might go back and forth between different mental spaces as they progress toward their goal. For example, they might make a list (Plan Meals), worry about budget (Buy Groceries), go to the store and realize a key ingredient is too pricey (Select Items), look up a recipe on the fly (Plan Meals), buy something off their list because they’re hangry (Select Items), then wonder if they forgot anything while they stand in line (Buy Groceries).

Reflect current (as-is) states, not future (ideal) states.

Because mental models are meant to help us understand design problems from users’ perspectives and unearth actionable insights, it follows that we should be mapping out users’ current reality rather than hypothesizing an ideal one. That exercise is best saved for service blueprinting or user journey mapping, once there’s a solid understanding of design opportunities to build upon.

Based on research, not hypothetical.

As a UX tool, a mental model is a method for organizing — and extracting insights from — primary and secondary user research. Therefore, the more extensive and rigorous the research is, the more useful the mental model will be as a design artifact.

Why use a mental model?

Like with any tool, mental models are incredibly helpful in some contexts and next to useless in others. So, when to use a mental model? Here are 3 scenarios where a mental model might actually be the tool you need to drive the design process forward.

If you don’t understand where a usability problem stems from in an existing product. Mental models can help to uncover points of friction between a product and its users’ understanding of how they should complete a goal. Those points of friction are key to understanding usability issues and can be helpful in forming hypotheses to test in design sprints.
If you’re working with multiple, varied personas and/or don’t have enough insight into user behavior to craft an effective user journey map. Sometimes you just don’t know enough to start mapping out a user journey. Mental models help us step back from the product and its conversion funnel to flesh out the user’s approach to the decision at hand. This enables us to set aside bias and recalibrate to the user’s needs and headspace before moving ahead.
If you’re working with service design. Good service design solutions often solve unmet needs that are invisible outside of the first-person experience. Mental models help designers to enter into that perspective and can help to illuminate points of friction that are design (and business) opportunities.

Like any other UX tool, mental models aren’t a prescriptive, one-size-fits-all approach to sourcing insights for experience design. As always, evaluate the design challenge and identify what information you need in order to move forward. Then choose the best tool to unearth that missing knowledge.

How do you create a mental model?

Because mental models are intended to help set aside bias, they’re best produced as a team rather than by an individual. Team members can help drive the brainstorming when stuck, point out blind spots and biases, and spot opportunities from multiple perspectives.

Here’s a rough outline of the process you might take in making a mental model. (Note that there are many approaches — see the Further Reading section at the bottom to explore the topic in more depth.)

In-progress mental model for booking a ski vacation.

Define your scope and goal(s). What information do you need in order to move forward? What user goal needs to be better understood?
Dig into the research. Gather any primary research documentation (e.g. user interview transcripts) and research artifacts (e.g. personas), and mine them for thoughts, feelings, and behaviors.
Group tasks into categories. Group thoughts, feelings, and behaviors into thematic groups — try arranging and rearranging them as you go.
Keep going. Brainstorm more tasks, be open to regrouping tasks or renaming categories when you see the logic start to misalign. Be sure you’re not thinking about this from a single persona or user’s perspective — what actions, thoughts, feelings would a secondary persona have?

Scour the mental model for points of friction. Where do users struggle? What requires significant cognitive load? Point those out with more sticky notes.
Generate insights for design opportunities. Explore points of friction for actionable insights — how could this be an opportunity to improve users’ experience?
[Optional] Create high-fidelity version. See the next section for a roundup of useful tools!

Tools for Building Mental Models

A giant wall or whiteboard plus some sticky notes and sharpies are all that you really need to build a mental model. However, if the mental model needs to be presentable, shared by remote teams, or live on for an extended time period, it’s best to put it in a digital format. Here are some tools that are useful for doing that:

Realtime Board simulates a whiteboard session in real time, letting users see contributions from all team members as they happen. You can even see where each teammate’s cursor is. The free version gives you access to most of the features and a limited number of boards.

Mental model mocked up using Realtime Board.

Whimsical is another web-based app similar to Realtime Board. It supports whiteboard-style sticky note collaboration as well as wireframing and flowcharts.

Google Sheets also does the job (though you lose the visual metaphor of the sticky note 😄).