There are so many resources on Design Thinking and Human Centered Design, and one of the major themes that I've found is the language is very inconsistent. It can be very overwhelming to try and understand these concepts and find that everyone is talking about something slightly different. I'd like to summarize some of the major points from Don Norman's The Design of Everyday Things (DOET, 2013) and give everyone in HCDC some common language for working together, as well as a good perspective to apply for your future work.

First off, let's talk principles: Don Norman's 7 Design Principles

Don Norman lays out 7 principles that all good designs excel in:

  1. Discoverability
  2. Affordances
  3. Signifiers
  4. Constraints
  5. Feedback
  6. Conceptual Model
  7. Mapping

We'll exemplify these principles by looking at my tape measure.


The moment you pick this up, you find that it has 3 interesting features.

  1. Some sort of switch or slider
  2. A tab
  3. A clip

As far as I know, these three features correspond with the only designed uses for this tape measure, so it has good discoverability: there is nothing that I'm supposed to do to this thing that doesn't make clear where I'm supposed to do it.


Now that we've discovered the features, we want to know what kinds of interactions we can have with with these features. This is what an affordance is: a possible two-way interaction between two agents – often a person and an object, but it could be between machines or even between people depending on what you're designing. For example, if something affords sliding it means that some external entity can cause some part of that thing to slide.

In this case, as we'll see, the tape measure only affords sliding when it is extended, clipping the tool to something, and pulling out the tape.


How do we know that these interactions are possible? If we look at the slider, enough of the mechanism is exposed to show a track on which the slider can slide. The design reveals very little that can be done with the tab, but given our pre-existing knowledge of handles it can easily be determined that this is something that should be pulled. Finally, while the clip maybe looks like it might afford rotation, the angled design signifies that it can be bent and thus you may bend it to attach it to something securely.


Feedback simply means that when you try and engage in some interaction the design gives you signals to indicate whether or not you're on the right path. Good feedback makes it clear what has happened and allows you to determine if you have accomplished your goal; bad feedback leaves people confused and induces frustration. The slider gives you feedback when it does not move while the tape is fully retracted, and once you pull the tape out it slides more freely. Once you slide it to a certain point, it feels as if you're pushing it over a bump and this lets you know that it is securely locked into place.


The major constraint of interest is in regards to the slider. As I mentioned above, when the tape measure is completely retracted the slider has an anti-affordance where it does not budge. This constraint, made clear by the feedback, tells you both that the locking mechanism only works with the tape pulled out and helps to create both the conceptual models and mapping of the device.

Conceptual Model

Based on all of this, how do we as the users of this device think this thing works? I told you that the constraint of only locking when it is retracted contributes to this; this is because, albeit maybe implicitly, you might come to see the slider as a clamp: when the tape is pulled you, you push the slider towards the tape to clamp it down and prevent it from moving.

The important point to note about conceptual models is that they need not be correct. It really doesn't matter if the mechanism is actually clamping the tape, so long as the model I create for how this device works leads me to the designers' intended usage of the product.


Finally, mapping is how well something communicates what the controls do. For example, if you want to move a car seat forward and back, there may be a switch that you press which moves the seat in the same direction as you are pressing it. This is an example of good natural mapping.

In this case, under our conceptual model of a clamp this device provides great mapping: you press it towards the tape to clamp down on it, and pull it away from the tape to release it. Note that in this case, the mapping is dependent on the conceptual model; and indeed, sometimes if the mapping seems unintuitive people will invent a new model to help them remember. However, good design makes this unnecessary, and the constraints this device has further clarifies the mapping: you can't lock it when it's fully retracted, which means that you quickly learn which is the locked position and which is the unlocked.

A Quick Note on Memory and Errors

To fully understand these points, I encourage you to read the Design of Everyday Things. In the interim, keep these facts in mind about human memory and "human" error in design:

  • People are not good with precision: we work best when are actions are "good enough" for the system. Design expecting people to make errors, and either correct them if you can or tell people what they need to do.
  • Human mental abilities are commonly misunderstood, and one of the biggest areas for misunderstanding is with memory. We can store about 5 items in our short term memory for about 30 seconds. If information is needed for longer than that, put it somewhere in your design – put the knowledge in the world, as Don Norman puts it.
  • Errors are usually due to bad design. Even if we like to blame people, and even if we blame ourselves when we fail to use something correctly, design is usually at fault. Don't blame the people: ask yourself how you can improve the design.

What is Design Thinking?

Design Thinking is incredibly simple on face value: it's all about problem solving, particularly when it comes to solving the correct problem. In fact, Don Norman claims that when he is given problems to solve he almost never solves the problem he was given: instead, he finds a bigger problem to solve. In design, the problems that we are asked to solve are either missing perspective, missing knowledge about human behavior, or both. This is where we come in.

The Double-Diamond Strategy

Source: ThoughtWorks

This strategy for problem solving gives an excellent way to apply design thinking to any problems you may be interested in solving. It begins by brainstorming what the problem actually is. The approach here is to keep asking why – one technique, aptly named the Five Whys, asks you to ask why five times to better understand your problem. Once you have a lot of perspective – pay special attention to the ideas that seem "dumb", as they are the ones that break you out of mental boxes – you define the problem. Once you reach this stage, you can move on to a similar process for creating a solution: brainstorm, go broad, and then narrow it down.

What is Human Centered Design?

Source: Skills Society

The Human Centered Design Process is simply a process to create something for someone. There are five steps that happen in a spiral, circling around but also rising up as each iteration brings you closer to your "product". Here are the five steps:

  1. Empathize: Understand what's going on in people's lives. See where they're running into problems. Observe them in their natural environment.
  2. Define: Based on what you've learned, synthesize this and consider the implications of what you've learned from people.
  3. Ideate: Start thinking of what needs to be done, taking special care to accept and consider every idea. Sometimes the inexperienced perspectives sometimes provide the freshness that you need.
  4. Prototype: Based on your ideas, start turning them into something that exemplify the idea(s) you've come up with.
  5. Test: Now that you have a prototype, test it out and see if it accomplishes its goal!

The interesting application here is that when combined with the Double Diamond model, we have a very solid approach to ensure that what we are designing meets peoples needs and solves the correct problem. In the first diamond, the "product" is coming up with the right problem. Important: test your problem! If you're not solving the real problem your final product can easily end up being useless. In the second diamond, the "product" is of course what you're designing to solve the identified problem.

Emphasis on the Empathy

Human Centered Design says that we design from our best conceptual model of the people who may use what we design. Make sure to really spend time with people, observe them, talk to them, feel their pains. Make what's personal to them personal to you, and it will greatly help you along on your development path.

How does this apply to me?

"All artificial things are designed." – Don Norman, on Page 2 of DOET

The above quote really spells it out: if you are creating some sort of artificial product, you are designing it. Therefore, the principles of design and the HCD process apply.

What are some areas where you can benefit from applying HCD?

  • Marketing Materials (Business and related majors): Marketing currently tries to rely on pre-existing understanding and expertise to market products. However, not only communicating with designers but also applying HCD to the creating of the materials will lead to increased discoverability of the product that consumers are missing.
  • Research (Especially in the Social Sciences): I was surprised to find out that, at least in Psychology, it's not that uncommon for experiments to utilize the HCD process to some extent. This includes activities such as talking to people during pilot testing, understanding their feedback, and see how the experiment experience can be made better. This, coupled with working to ensure you're solving the correct problem, will lead you to more insightful findings and more valid, reliable work.
  • Physical Products (Engineers, GrC, Art): This one is quite straightforward. Engineers in particular love to make things; design thinking will help you to understand if something should be made, and if so how should it be made to meet people's needs.
  • Theories and Ideas (Everyone): Any sort of argument you make is artificial. Any sort of work you produce meant to help people understand something is a construct of language, which means the principles of design apply. You're often told to consider your audience, but why not get to know your audience and talk to them throughout? Building empathy will make your work that much better.
  • Software (Anyone writing software): Poor design in software is everywhere. Software can be developed so quickly, and so often those writing it feel that since they know how to use it their users should do. Even if you don't want to go into design necessarily, learning the principles of design will help you to write better code and be critical of possible design directions.

The Practicality of Human Centered Design

Human Centered Design sounds great. It sounds like you're always going to make something that people need and love. However, Don Norman made a law regarding the situations where you might want to apply HCD.

Don Norman's Law of Product Development: The day a product development process starts, it is behind schedule and above budget.

With this in mind, it's important to proceed with the strategies in mind:

  • Always work in multi-disciplinary teams: keeping everyone involved in a product's development involved throughout the process ensures that what the designers envision is what the users get.
  • Always have people in the field building empathy, understanding people, and bringing this information back so that you don't have to wait until you're developing something to have a sense for what people need and want to do.


First off, let me warn you: don't use this all at once! This is a lot to take in. Instead, I invite you to start to notice design around you. Think about the design principles; apply them; question the design of everyday things. Then, as you grow your design awareness, come back to these principles and start applying Design Thinking and Human Centered Design to what you're passionate about!