CrowdScience listener Nyok, in South Sudan, is right-handed and has always felt very creative. He's also noticed that left-handed people seem to be more logical. He's wondering if this has anything to do with the idea that different sides of your brain can be dominant for different tasks.

We covered the basics on hand preference three years ago, in a CrowdScience episode called ‘Why aren’t we all ambidextrous?’, so presenter Caroline Steel delves into the archive to find out about the evolution of hand preferences. Psychologist Sebastian Ocklenburg from MSH Medical School in Hamburg, Germany, and neuropsychologist Marietta Papadou Pastou from the National and Kapodistrian University of Athens in Greece, explain why most people are right-handed and why we think cultural differences are also a factor.

In that show Caroline also spoke to neuropsychologist David Carey from the University of Bangor in Wales. He was so fascinated by Caroline’s answer to a test question that he invited her for a brain scan. Three years later – thanks to Nyok’s question - she’s finally taking him up on the offer!

Caroline is mixed handed, which means that she prefers her left hand for some tasks and her right hand for others. So what can an MRI scan tell us about which side of her own brain she’s using? Richard Binny, Director of the Bangor Imaging Institute, slides her into the machine before David talks her through the results.

But does which hand you prefer really predict whether you’re more creative, or more logical?

Presenter: Caroline Steel Producer: Margaret Sessa-Hawkins with Sam Baker Editor: Ben Motley