The Design Psychologist | Psychology for UX, Product, Service, Instructional, Interior, and Game Designers

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How many users do you actually need for a usability study?
In this episode of The Design Psychologist, Thomas Watkins talks with Laura Faulkner about one of the most repeated ideas in UX research: that five users are enough. Laura explains why that rule of thumb can be useful in some situations, but dangerous when teams treat it like a law.
They discuss sample size, research risk, stakeholder alignment, and why the real question is not “How many users?” but “What decision are we trying to support, and what happens if we miss something important?”
Laura also shares practical advice on making research more influential inside organizations: sharing early and often, treating research as community property, helping stakeholders take ownership of findings, and building a point of view from human data rather than personal opinion.
The conversation also explores synthetic users and AI, including where AI can help researchers think through test plans and where teams still need fresh data from real people.
If you want to design better studies, communicate findings with more impact, and help research actually change product decisions, this episode gives you a grounded, human-centered way to think about evidence, risk, and influence.
If today’s conversation helped you think more deeply about your work, I’d love it if you left a quick rating or review on Apple, Spotify, or your favorite podcast listening app. It helps more thoughtful designers discover the show—and keeps these meaningful insights coming your way. Just a star rating or a sentence or two makes a big difference. Thanks for listening! 
If this show has been useful or thought-provoking for you, please do us a favor and help other people discover the show by leaving a rating and review on your favorite podcast player.
To leave a review on Apple Podcasts: search for The Design Psychologist, tap the show, scroll down to the bottom of the page, and hit “Write a Review.”

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What does it actually mean to say a product is usable?
In this episode of The Design Psychologist, Thomas Watkins talks with Phil Kortum about the System Usability Scale, or SUS: one of the most widely used tools for measuring usability. They discuss why this 10-item questionnaire has lasted for decades, what makes a usability metric trustworthy, and how researchers can use SUS scores to compare products, track improvement, and communicate usability in a shared language.
The conversation covers why a number is not automatically objective, how SUS differs from measures like Net Promoter Score, when the positive version of SUS may be better to use, and why usability researchers still need effectiveness and efficiency measures alongside subjective ratings.
They also explore Phil’s work on voting systems, where usability is not just about convenience but whether people can successfully cast a vote.
If you want to understand how to measure human experience with more rigor, this episode gives you a clearer way to think about usability, evidence, and the difference between a score that sounds scientific and a metric you can actually trust.
If today’s conversation helped you think more deeply about your work, I’d love it if you left a quick rating or review on Apple, Spotify, or your favorite podcast listening app. It helps more thoughtful designers discover the show—and keeps these meaningful insights coming your way. Just a star rating or a sentence or two makes a big difference. Thanks for listening! 
If this show has been useful or thought-provoking for you, please do us a favor and help other people discover the show by leaving a rating and review on your favorite podcast player.
To leave a review on Apple Podcasts: search for The Design Psychologist, tap the show, scroll down to the bottom of the page, and hit “Write a Review.”

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How do you know whether a product idea is worth building before you spend months designing and developing it?
In this episode of The Design Psychologist, Thomas Watkins talks with Jaime Levy, author of UX Strategy, about how designers, researchers, founders, and product leaders can move beyond opinion and make a stronger evidence-based case for what to build.
Jaime explains why strategy is not about magically predicting the future, but about systematically reducing risk. She discusses how storyboards can help teams test the business idea before getting lost in interface details, why most companies compete in “purple oceans,” and how UX can become a source of real differentiation.
The conversation also gets into AI: where it can speed up strategy work, where it can mislead us, and why human judgment, critical thinking, and customer understanding matter even more as tools become more powerful.
If you care about building products people actually want, this conversation will help you think more clearly about value propositions, mental models, product differentiation, and the role of UX strategy in a rapidly changing world.
If today’s conversation helped you think more deeply about your work, I’d love it if you left a quick rating or review on Apple, Spotify, or your favorite podcast listening app. It helps more thoughtful designers discover the show—and keeps these meaningful insights coming your way. Just a star rating or a sentence or two makes a big difference. Thanks for listening! 
If this show has been useful or thought-provoking for you, please do us a favor and help other people discover the show by leaving a rating and review on your favorite podcast player.
To leave a review on Apple Podcasts: search for The Design Psychologist, tap the show, scroll down to the bottom of the page, and hit “Write a Review.”

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Season 2 of The Design Psychologist is here.
After exploring the foundations of psychology across human factors, UX, instructional design, service design, game design, and more in Season 1, this season takes the conversation even further.
We’re asking some honest—and sometimes difficult—questions about where design psychology is today, the challenges professionals are facing in their careers, and how we can use design to create a better future.
Throughout Season 2, we’ll explore topics including accessibility, data visualization, helper robots, Jobs to Be Done vs. classical human factors methods, tools for expanding the power of the mind, and the growing role of AI.
You’ll also hear conversations with fascinating guests, including an author behind one of the most controversial and influential articles in UX research and a YouTube creator and memory expert.
And there are a few surprises along the way.
If you’re interested in psychology, design, UX, human factors, emerging technology, or simply understanding how people interact with the world around them, Season 2 has plenty to explore.
Welcome back to The Design Psychologist.

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What happens when human-centered design is no longer enough?
Designers are trained to make things easier to use—but what if ease and elegance are no longer the point? What if the systems we need to change go far beyond screens and interfaces, touching global structures and collective futures?
Our guest, Don Norman, coined the term "Norman Door" to describe a door that gives the wrong signal about how to open it—pull vs. push—highlighting poor affordances and feedback in everyday objects. 
This simple yet profound observation helped launch a new era of design awareness, making him one of the most influential voices in the psychology of design. His decades-long career has shaped the fields of human-computer interaction, design thinking, and usability. He is the author of the seminal book The Design of Everyday Things, and now, Design for a Better World, a work that challenges us to design for the full complexity of human and planetary needs.
WHAT WE COVER IN THIS EPISODE
What makes some errors easy to catch and others dangerously hard to detect
How decades of design decisions have shaped today’s global challenges
What it means to shift from human-centered to humanity-centered design
How co-design empowers communities over outside experts
The surprising design lessons learned from nuclear accidents, faucets, and guinea pigs
The role of failure in progress—and why we should embrace it

KEY TAKEAWAYS
Designing for ease is not enough—today’s challenges demand designing for systems and long-term impact.
User-centered design can fall short when it fails to consider environmental, societal, and ethical dimensions.
Human error is not always a failure of attention—it’s often a byproduct of bad design.
To scale real change, we need dandelion models—spreading seeds of knowledge and training others to do the same.
Participatory design ensures that communities are not passive recipients but active creators of their own solutions.
The service economy offers a path toward sustainability—if companies rethink profit and longevity.
The future of design psychology isn’t about better buttons—it’s about understanding people so deeply that we can redesign society itself.

If today’s conversation helped you think more deeply about your work, I’d love it if you left a quick rating or review on Apple, Spotify, or your favorite podcast listening app. It helps more thoughtful designers discover the show—and keeps these meaningful insights coming your way. Just a star rating or a sentence or two makes a big difference. Thanks for listening! 
If this show has been useful or thought-provoking for you, please do us a favor and help other people discover the show by leaving a rating and review on your favorite podcast player.
To leave a review on Apple Podcasts: search for The Design Psychologist, tap the show, scroll down to the bottom of the page, and hit “Write a Review.”