HCI Explained

Your brain has a budget. Good design either spends it wisely or blows it.

Not all mental effort is the same — and that distinction turns out to matter enormously for how we design things people actually want to use. Cognitive load theory started in educational psychology, but its core insight migrated quietly into UX and product design, where it shapes decisions from the layout of a settings screen to the way a checkout flow asks for your address.

This episode traces that idea carefully: where it came from, what the three types of cognitive load actually describe, and why "just make it simpler" is a more complicated instruction than it sounds. The hosts look honestly at where the research holds up, where it gets fuzzy, and what happens when designers reduce the wrong kind of effort — or accidentally strip out the kind that's genuinely useful.

• Why intrinsic load isn't the enemy, even when it feels like friction

• The extraneous stuff that quietly exhausts users without their noticing

• The third kind of load — the one that actually builds understanding over time

• A real product example where simplifying made the experience measurably worse

Whether you work in interface design, teach anything to anyone, or just find yourself wondering why some apps feel effortless and others feel like homework, this conversation offers a useful lens. No prior knowledge of HCI or cognitive science needed — just curiosity.

Pull up something you use every day before you listen. You'll look at it differently after.

Your mental model of an app and the designer's rarely match — and that gap explains a lot.

Every time you tap something and get a surprise, every time a feature hides somewhere you'd never look, every time a tool feels like it's working against you — there's a good chance you're bumping into a mismatch between the map in your head and the one the designer drew. That gap has a name in human-computer interaction research, and understanding it changes how you see almost every digital experience you have.

In this episode, we get into the idea of mental models: the informal, often unconscious pictures users build of how a system works. We look at where those pictures come from, why they almost never perfectly match the system's actual logic, and why that matters whether you're the person building something or the person trying to use it. The examples are grounded in research — not hypothetical, not hype.

A few of the things we explore along the way:

• Why two people can use the same interface and come away with completely different internal maps of how it works

• A classic analogy that makes the whole concept click — and why it's both useful and imperfect

• Real documented cases where the model mismatch caused genuine confusion, not just minor frustration

• Where thoughtful designers and researchers actually disagree about whose job it is to close the gap

This is a calm, source-grounded conversation for anyone curious about why digital things feel the way they do.

The word "affordance" is everywhere in design — and almost always wrong.

Don Norman borrowed a term from ecological psychology, put it at the heart of design thinking, and then watched it get mangled for three decades. Designers use it to mean roughly "what something looks like it does" — but that's not quite what Norman meant, and the gap between those two ideas turns out to matter enormously for how we build things people can actually use.

This episode is a careful look at where the word came from, what it was always trying to point at, and why Norman eventually introduced a second term — signifier — to rescue the conversation. We follow the idea from a psychologist studying how animals perceive their environment all the way to the door handles, app buttons, and everyday objects that quietly shape human behaviour every day.

A few of the threads we pull on:

• The original definition, from James Gibson, and why it has almost nothing to do with design

• What Norman actually argued in The Design of Everyday Things — and what he later said he got wrong

• A real product that failed because its designers confused the two concepts

• The quiet ethical question underneath all of this: who decides what an object "invites" someone to do?

None of this requires a background in HCI or user experience research. If you've ever pushed a door that was meant to be pulled, or tapped something on a screen that turned out not to be a button, you already understand the problem this episode is about. The theory just gives you a cleaner way to think about why that keeps happening.

Calm, unhurried, and worth your attention.

What makes a button feel clickable — and what happens when it doesn't?

A button seems like the simplest thing in design. Press it, something happens. But beneath that transaction sits a surprisingly rich set of decisions: about visual signals, about feedback, about what it even means for an interface element to feel interactive. Get those decisions right and users never notice. Get them wrong and frustration accumulates in ways that are hard to diagnose and easy to blame on the user.

This episode takes apart the humble button — its states, its affordances, the small cues that make it feel alive or dead — and traces why something so ordinary turns out to be genuinely difficult to do well. The hosts move from the research that first named these ideas to the real products where the trade-offs play out, and they don't shy away from the counterarguments along the way.

A few of the threads the episode pulls on:

• Why the word "affordance" means something more specific than most design conversations let on

• What button states actually are, and which ones tend to get quietly dropped in production

• The case for flat design — and what was lost when skeuomorphism left

• How touch, cursor, and voice interfaces each change what a button needs to communicate

Whether you work in UX, care about the software you use every day, or just find yourself curious about why some interfaces feel effortless, and others feel like guesswork, this one is worth sitting with.

Your font is already talking. The question is whether you're listening.

Before you read a single word, the typeface carrying it has already made an impression — formal or casual, trustworthy or playful, easy or exhausting. That's not a metaphor. It's a measurable effect that shapes how people feel about the content, the interface, and the organisation behind it.

In this episode, we slow down and look carefully at one of the most overlooked layers of digital design: typography. Not as decoration, but as a communicative act. We draw on research into readability and personality, trace how type choices encode meaning, and ask what it actually costs — in comprehension, trust, and usability — when those choices go wrong.

A few of the threads we pull on:

• Why two typefaces that are equally legible can produce completely different emotional responses in readers

• How the distinction between a typeface's personality and its readability creates real tensions for designers

• What happens when display fonts built for headlines end up doing the work of body text

• The surprising places where what feels more readable isn't always what performs better in studies

This is an episode for anyone who has ever squinted at a screen, wondered why one app feels friendlier than another, or made a design decision based on instinct and hoped for the best. We don't assume prior knowledge of typography, UX, or human–computer interaction — just curiosity.

Take a closer look at something you read every day.

One in twelve men can't read your colour-coded design the way you intended.

That's not a niche accessibility footnote — it's a quiet, persistent failure woven into the fabric of everyday UX. Colour is one of the most powerful tools in a designer's kit, and one of the most routinely misused. This episode of HCI Explained asks a deceptively simple question: if you design with colour alone, who gets left behind, and why does it keep happening?

Hosts Mara and Jon walk through the human–computer interaction research on colour perception and contrast, unpacking what "colour blindness" actually means (it's rarely true blindness), how contrast ratios became a cornerstone of accessibility standards, and why well-intentioned design teams still ship products that exclude millions of users. The episode moves from theory to practice without getting lost in technical detail — this is a conversation for curious people, not specialists.

A few of the threads we pull on:

• Why the 1-in-12 statistic is both accurate and misleading, and what the real number looks like when you count everyone affected

• The everyday analogy that reframes how you think about colour dependency in interfaces

• A real product launch where colour-only feedback caused genuine, documented user confusion

• The tension between visual delight and functional equity — and whether designers are ever forced to choose

No jargon goes undefined, no conclusion is handed to you cheaply. Just a careful, unhurried look at something that shapes every screen you use.

Pull up a chair — this one's worth thinking about.

Your eye moves before your brain does. Visual hierarchy is why.

Every screen you use has been designed — consciously or not — to pull your attention in a particular direction. The size of a heading, the weight of a typeface, the breathing room around a button: none of it is arbitrary. Researchers have been studying how people scan and read interfaces for decades, and what they've found is both fascinating and a little humbling for anyone who designs for a living.

This episode traces that research into the real world. Hosts Priya and Tom open with a simple question — why do some pages feel instantly readable while others leave you hunting? — and work outward from there, moving through the underlying perceptual science, the genuine difficulty of building hierarchy into complex products, and the moments when the conventional wisdom doesn't quite hold.

A few of the threads they pull on:

• why size and contrast do most of the heavy lifting, and where that breaks down

• how whitespace functions as a signal, not just decoration

• the tension between business priorities and a clean visual path — a trade-off that's messier than most design writing admits

• what happens to hierarchy on small screens, where the usual tools are suddenly in short supply

The conversation is unhurried and grounded in HCI research, written for curious listeners who don't need to work in UX to find this worth thinking about. Whether you've spent years designing user interfaces or just noticed that some apps feel easier to use than others, there's something here worth sitting with.

Pull up something you use every day and take a closer look before you hit play.

Your eyes decide what matters before your brain knows you're looking.

Most of us assume we read a screen the way we read a book — left to right, top to bottom, taking it all in. But decades of eye-tracking research tell a different story. Attention moves in jagged, skipping patterns, guided by visual weight, contrast, and position in ways that happen well below conscious awareness. Understanding that gap — between what the eye catches and what the mind processes — is one of the quieter revolutions in how we think about interface design.

In this episode, hosts walk through the perceptual science behind how people actually scan digital interfaces, from the moment a page loads to the fraction of a second before a decision gets made. The conversation draws on real research and concrete examples to show how the architecture of a screen shapes behaviour in ways designers often don't intend — and users rarely notice.

• Why the path attention takes across an interface is rarely the one designers imagine

• What eye-tracking studies reveal about the difference between looking and seeing

• Where good intentions in layout and hierarchy quietly go wrong

• The genuine tensions in the field — because not everyone reads the evidence the same way

Whether you work in UX, care about user experience more broadly, or simply spend your days looking at screens, there's something here that will change how you notice the designed world around you.

New episode out now — and next time, we're going somewhere just as close to home.

Why does a button feel clickable?
Why do some interfaces feel intuitive almost instantly?
And why can cluttered apps feel exhausting to use?

The answer often comes back to a set of ideas from early psychology known as Gestalt principles.

In this episode of HCI Explained, we explore how principles like proximity, similarity, figure-ground, continuity, and closure quietly shape the way people perceive digital interfaces every day.

We break down how designers use these principles in products like Netflix, Gmail, Figma, iOS, and Android to guide attention, organise information, and reduce cognitive load without users even noticing.

Along the way, we unpack:
• Why the human brain naturally groups things together
• How spacing can completely change usability
• Why visual hierarchy matters more than decoration
• Common interface mistakes that violate Gestalt expectations
• How to start recognising these patterns in everyday apps

This episode is designed for anyone curious about design, UX, psychology, or how interfaces communicate visually without words.

User research did not always look like Zoom calls, heatmaps, and analytics dashboards.

In this episode of HCI Explained, we trace how researchers studied people and technology from the 1980s to today. We explore the rise of usability labs, contextual inquiry, ethnographic fieldwork, remote testing during COVID-19, and the growing role of behavioural analytics in product design.

Along the way, we unpack why user research methods changed, what was gained, what was lost, and why modern UX teams increasingly combine interviews, observation, experimentation, and large-scale behavioural data.

If you have ever wondered:
• Why companies moved away from traditional usability labs
• How remote research changed the industry
• Why analytics alone cannot explain human behaviour
• How researchers choose methods today

…this episode is for you.

Whether you are new to HCI, a UX student, or an industry practitioner, this episode offers a practical and historical introduction to how user research evolved into what it is today.