Here’s a fairly simple machine but I think it’s a rather good example of the ways in which poor design can make it more likely that the user will make a mistake.
On the left there is a panel with four buttons with an arrow pointing to something on the screen. Pressing a particular arrow activates the option on the screen next to it. Or at least it should…
Unfortunately, in the example below the match-up between the buttons and the options has come unstuck. Which button should you press to get £30? You might feel a bit short-changed if you press the button that’s next to it.
Picture credit: Cash machine buttons