How you respond to a sensation such as tickling depends on whether it is created by you or someone else.

Little brain

The cerebellum, or ‘little brain’, is found at the nape of the neck. It is central to the control of our bodies’ movements but it is also thought to play a crucial role overseeing cognitive processing. Think of the brain like a factory with different parts processing different information and the cerebellum is the quality control supervisor. Neuroscientists suspect that the cerebellum sends signals to dial down the perception of tickling in the somatosensory cortex when it is our own fingers, not someone else’s, at work. Dr Kilteni’s fMRI studies lend weight to that hypothesis.