The marshmallow experiment is a fun and interesting activity with a 4-year old. Francine is turning 4 in a few months so we thought she might be up for it. In the test, the 4-year old is given one marshmallow and told they can eat it now if they like. But, if they can wait for 20 minutes without eating it, they will be given another one. So here's ... Read Morehow we did it for Francine. We put her in a room and gave her one marshmallow. I told her the rules and left her alone in the room for about 2 minutes. When I came back, I had chocolate syrup with me and I poured some on her marshmallow. I then left her for another 3 minutes. It's very interesting to watch how she tried to keep herself 'busy' and try hard to not eat the marshmallow. If you have a 4 year old, you should try it!!