Have you ever said a friendly hello to someone and then got caught in a long, drawn-out conversation?
You might’ve wanted out of it, but couldn’t think of a polite exit.
Because there’s no way undo that hello, you might begin to avoid such niceties in the future.
User Control and Freedom is one of Jakob Nielsen’s ten usability heuristics.
It states that users often choose system functions by mistake, and need a clearly marked
“emergency exit” to leave that unwanted state.
Basically: support undo and redo.
A common example would be the back and forward buttons on every web browser.
Imagine if that didn’t exist!
You’d have to be really confident in every single click as you navigate around the web,
because there’d be no easy way to get back to where you were if you clicked to visit
a page and realized it wasn’t what you needed.
Similarly, any process or mode in any digital system should include a way for users to back
out when needed.
And websites can’t only rely on those browser buttons, but should provide users a clear
way to leave a stepped process or cancel whatever it was they started on that web page itself.
Undo or cancel is particularly important for mobile devices and other touchscreens, where
accidental taps are common.
And again, these “emergency exits” should be clearly marked.
For instance, many people have no clue that some mobile apps allow undo by shaking the
device just like you could shake-to-erase the classic Etch A Sketch toy!
If users never discover a feature, does it even exist?
When it’s easy for people to back out of unwanted processes or undo an action, it fosters
a sense of freedom because realize they don’t need to be afraid to click on that link or
test out that photo filter — they know that if it turns out to not be what they wanted,
they can easily undo that action.
They’re always in control of the system, and aren’t going to get stuck somewhere they didn’t intend.