The placebo effect of the ‘Close Doors’ Button

20Feb09

Apparently, the ‘close doors’ button on most lifts does not actually work. It is there mostly to give passengers the illusion of control. We press it but the lift control mechanisms decide when the doors should actually shut according to their pre-programmed cycles.

Human brains are finely tuned belief engines. Millions of years of evolution have honed our grey stuff to spot causation in the world and form beliefs about what causes what. It helps us survive when we notice that certain events always follow other events. Such knowledge helps us reliably find food, mates and shelter. But our brains are taking efficient shortcuts. We filter out and ignore failures and remember and reinforce successes. And most of the time this works. But beliefs formed in this way can lead to mistakes. My pressing the lift button may well be a false conclusion drawn from my experience because I have failed to spot hidden causes and alternatives to the obvious. Maybe it really is just the lift closing the door without my intervention.

This all is related to the illusion of control psychological effect studied by Ellen Langer and others, where people are shown to believe they have some control over things they clearly don’t: in most cases, a button does afford us control, and we would rationally expect it to, and if we’re used to it not doing anything, we either no longer bother pressing it, or we still press it every time “on the off-chance that one of these days it’ll work”.

By now you should be wondering why the hell lift makers should install the close door button in their lifts if it doesn’t work appropriately.
There are a few options:

• The button really does work, it’s just set on time delay.
  Suppose the elevator is set so that the doors close automatically after five seconds. The close-door button can be set to close the doors after two or three seconds. The button may be operating properly when you push it, but because there’s still a delay, you don’t realize it.
• The button is broken. Since a broken close-door button will not render the elevator inoperable and thus does not necessitate an emergency service call, it may remain unrepaired for weeks.
• The button has been disconnected, usually because the building owner received too many complaints from passengers who had somebody slam the doors on them.
• The button was never wired up in the first place.

But thinking about this more generally: how often are deceptive buttons/controls/options – deliberate false affordances – used strategically in interaction design? Are there any examples of products (other than, say, children’s toys) deliberately designed with fake controls to make the user feel in charge even though he/she isn’t?

Filed under: Design, Interaction, Psychology   |  35 Comments