Stevan Nikolin reckons he's volunteered for more than 50 scientific studies in the past ten years.

The most bizarre study he remembers was being asked to move his little finger, and only his little finger, non-stop for two minutes. The researchers were interested in how much force the muscle that moves the little finger from a from a closed hand position to an open one.

In the second episode of Science is Golden we explore what motivates people to volunteer for research.