UX doesn’t use psychology. It quotes it. And often, it’s quoting from outdated textbooks.
Let’s be clear. Psychology has absolutely shaped UX. Many foundational principles we apply today come directly from it:
Hick’s Law (choice overload)
Miller’s 7 ± 2 (memory capacity)
Fitts’ Law (target acquisition time)
Gestalt Principles (perception)
These are all useful tools. They help us design faster, defend decisions more easily, and teach others to think systematically. But we have to admit: we often invoke these principles like gospel. Fixed. Unchanging. Sacred.
“Don’t make me think.”
“Reduce cognitive load.”
“Limit the number of choices.”
We say these phrases as if they’re beyond questioning. But what happens when we step back and ask: Who said that? When? Under what conditions? For which users?
Users can only hold seven things in short term memory, therefore this nav bar is wrong.”
Except… that study was from 1956, and the paper itself was called “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information.
Not a law. A limit. A discussion.
2. UNIVERSALITY IS A LIE
The idea that one heuristic works for all users, across all cultures and contexts, is naive.
Our users are not lab rats sitting in front of a monochrome monitor with a single button mouse. They are real people:
Navigating apps in different languages
With varying cognitive and physical abilities
Carrying emotional histories and expectations shaped by culture, age, trauma, and more
Yet we keep using the same playbook. We need to ask ourselves: Are we designing for today’s users, or just reenacting yesterday’s insights?
3. SELECTIVE APPLICATION
UX loves the safe parts of psychology:
“Users don’t like friction.”
“Shorter paths convert better.”
“Attention spans are shrinking.”
But we often ignore the complex, messy areas:
Trauma informed design
The ethics of behavioral nudges
Cultural differences in visual cognition
Motivation, trust, emotion, long term engagement
If we truly want to use psychology, we have to go deeper. That means reading past the bolded bullet points. That means doing the work.
Not at all.
These principles are useful. They’ve helped shape great products and create shared understanding between designers, engineers, and stakeholders. I’m not saying we should throw them out. I’m saying we should understand where they come from, question how we use them, and update them when necessary.
It’s more than OK to use Fitts’ Law. It’s smart. But it’s even smarter to ask: Does this still apply here? For these users? On this device?
Even physics laws get challenged by physicists.
UX heuristics should be challenged by us.
UX is still a young discipline. That means we’re still defining its best practices, not just inheriting them. If we don’t evolve the field, it will stagnate. If we don’t question what we’re taught, we become tool users instead of toolmakers.
We can’t keep quoting old psychology like scripture and calling it strategy.
Let’s use those principles. But let’s also be critical, curious, and courageous enough to challenge them, so that UX continues to grow not as a set of fixed rules, but as a living, thinking practice.