Science Buddies: "Ask an Expert"

Hi!
I was thinking about doing the Science Buddies project about whether or not young children can determine between if something is candy or medicine (4-6 year olds.)
The science fair judges last year weighed scores heavily on making sure that students had a control in their experiment.
In an experiment like this, how would you determine what the control is when it involves human behavior?
Thank you!

Hi,

What would your materials, methods, and procedures be?

This will help to determine a control for your experiment.

Thank You!