Rights: The Royal Society, TVNZ 7 in partnership with the Ministry of Research, Science and Technology. Published 15 December 2010 Download

This is a simple explanation of what the placebo effect is and how it works.

This one minute animated video from TVNZ aims to demystifies commonly used, but little understood scientific and technological jargon.


What is the placebo effect?

The placebo effect occurs when someone is given a treatment - such as a sugar pill - with no known medical value and their symptoms improve. The person believes it’s going to work - so it does.

It’s like putting a plaster on a sore knee – a child may feel better even if there’s no medical reason.

Taking a placebo can create a measurable physical reaction – raise pulse rate and reaction speed if someone thinks they’ve taken a stimulant - or make them sleepy if they’re told it’s a sedative.

Brain imaging shows that believing a treatment will work can affect the level of chemical messengers and hormones that signal pleasure or pain.

On average, a third of all patients are susceptible to the placebo effect.

And that’s the placebo effect.