Many of us experience an inner voice: we silently talk to ourselves as we go about our daily lives. CrowdScience listener Fredrick has been wondering about the science behind this interior dialogue. We hear from psychologists researching our inner voice and discover that it’s something that begins in early childhood. Presenter Caroline Steel meets Russell Hurlburt, a pioneering scientist who devised a method of researching this - and volunteers to monitor her own inner speech to figure out what’s going on in her mind. She discovers that speech is just part of what’s going on in our heads, much of our inner world in fact doesn’t involve language at all but includes images, sensations and feelings. Caroline talks to psychologist Charles Fernyhough, who explains one theory for how we develop an interior dialogue as young children: first speaking out loud to ourselves and then learning to keep that conversation going silently. No one really knows how this evolved, but keeping our thoughts quiet may have been a way of staying safe from predators and enemies. Using MRI scanning, Charles and Russell have peered inside people’s brains to understand this interior voice and found something surprising: inner dialogue appears to have more in common with listening than with speaking. Caroline also has an encounter with a robot that has been programmed to dialogue with itself. Which leads us to some deep questions: is our inner voice part of what makes us human, and if so, what are the consequences of robots developing this ability? Scientist Arianna Pipitone describes it as a step towards artificial consciousness. Featuring: Professor Charles Fernyhough, University of Durham, UK Professor Russell Hurlburt, University of Nevada, Las Vegas, USA Dr Arianna Pipitone, University of Palermo, Italy Presenter: Caroline Steel Producer: Jo Glanville Editor: Cathy Edwards Sound design: Julian Wharton Studio manager: Donald MacDonald Production co-ordinator: Ishmael Soriano (Image: Mixed Race boy looking up Credit: Jose Luis Pelaez Inc via Getty Images)