Tognazzini’s First Principles

Sixteen working rules for designing software that respects the user.

Bruce “Tog” Tognazzini’s First Principles of Interaction Design, written and refined on AskTog.com over decades at Apple, Sun, and Nielsen Norman Group. Less a catechism than a working set of rules — each one earned from products that shipped and patterns that scaled.

Origin

Bruce ‘Tog’ Tognazzini was Apple employee number 66, wrote the company’s first human interface guidelines, and shaped the look and feel of the early Macintosh across fourteen years and eight editions of the guidelines.

After Apple he worked at Sun and WebMD before joining Nielsen and Norman as the third principal of Nielsen Norman Group. His First Principles of Interaction Design, published on his site AskTog since 1978 and continuously revised, collect the craft into one canonical list.

The Principles

A living checklist of interaction design fundamentals — anticipation, autonomy, consistency, discoverability, efficiency, explorable interfaces, Fitts’s law, latency reduction, learnability, and more.

Coined by
Source
First Principles of Interaction Design, AskTog
In practice
Audit flows against the checklist
Foresight

Anticipation

Bring to the user whatever they’re likely to need next — information, tools, options — before they have to ask. Anticipating the next action is what separates a competent tool from one that feels intelligent.

Defined
Bring what’s next, now
Examples
Suggested actions · pre-fill
Feels like
Intelligence
Control

Autonomy

The user, not the system, is in charge. Show status clearly, never trap people in a flow they can’t escape, and make rules explicit so they can be steered around. Software that decides things for the user without asking is software that gets uninstalled.

Defined
User holds the wheel
Show
Status · way out
Don’t
Trap or decide silently
Sameness

Consistency

The same action should look and behave the same everywhere — within the product, across the suite, and against platform conventions. Inconsistency is unforced cognitive load. Break it only when you have a much better answer and only at one point in the flow.

Across
Screens · suite · platform
Cost
Of breaking it: relearning
When break
A much better idea
Smart starting point

Defaults

Give users a safe starting state. Defaults should be reversible, useful for most users in most cases, and clearly chosen — not “we forgot to pick.” A great default does the work the user was about to do anyway, and gets out of the way.

Properties
Safe · reversible · sensible
Source
IP · history · most common
Don’t
Use as a dark pattern
Speed

Efficiency of the User

Optimize the user’s time, not the system’s. Saving the engineer ten seconds at the cost of ten user-seconds, ten thousand times a day, is a bad trade. Bulk actions, keyboard shortcuts, smart pasting, and recent items all hand minutes back to the people who do the work.

Optimize
User’s seconds
Tactics
Bulk · shortcuts · recents
Test
Run it 100 times
Discoverability

Explorable Interfaces

Reward curiosity. Let users try things without fear — actions should be obvious to find, and obvious to reverse. Tog’s note: every action needs a way back. Without undo, every click is a commitment, and most users stop clicking.

Defined
Safe to try, easy to back out
Require
Undo for everything
Effect
Confidence to explore
Performance

Latency Reduction

Where the system can’t get faster, make it feel faster. Optimistic UI commits the change before the network confirms; skeleton screens give the eye something to land on; sound and animation acknowledge a click before the response arrives. Perceived latency is design’s lever.

Lever
Perceived > actual latency
Tactics
Optimistic UI · skeletons
Risk
Lying about success
Trust

Protect the User’s Work

The single most important rule. Auto-save constantly, recover from crashes, version everything, never silently overwrite. Tog: nothing erodes trust faster than losing a user’s work. Once it happens, that user reaches for their save key compulsively, forever — or stops using the product.

Rule
Never lose work
Tactics
Auto-save · history · recovery
When lost
Trust never fully returns
Continuity

Track the User’s State

Remember where the user left off. Open the document they were editing, scroll to the line they were reading, restore the filter they had applied. Continuity across sessions costs little to ship and saves the user from rebuilding their workspace every morning.

Track
Position · filter · selection
Across
Sessions · devices
Result
Less rebuilding
Wayfinding

Visible Navigation

Users should never wonder “where am I, where can I go, and how do I get back?” Visible nav, breadcrumbs, and clear active states cost a few pixels and pay for themselves in every session. Tog called this the single most missed principle in modern web design.

Show
Where · where else · back
Pairs with
Cost of skipping
Lost users

Tog’s Principles in the Age of AI

Anticipation and latency reduction — two of Tog’s oldest principles — are exactly the levers a model gives you, and exactly the levers it threatens to break.

✦ AI Era

Anticipation at Scale

Tog’s anticipation principle was about hand-picked next-actions. Models do it generatively, per user, per moment. Done well, it’s the closest software has come to “feels intelligent.” Done sloppily, it’s a constant stream of guesses that aren’t quite right, and the user starts ignoring the suggestions.

Done well
Feels intelligent
Done badly
Noise · users tune out
Test
Take rate > 30%?
✦ AI Era

The Latency Trade-off

Models are smart, but they’re not fast. A response that takes four seconds violates everything Tog wrote about latency. Streaming tokens helps; pre-warming the model helps; skeleton answers help. Without those, even a great answer arrives feeling like a slow product.

Problem
Smart but slow
Tactics
Stream · pre-warm · skeleton
Rule
Never silent for > 1s
Further Reading