 The hypothesis that she investigated proposes that trepanation improves cerebral circulation by allowing the "full heartbeat" to express itself inside the cranial cavity, which Feilding hypothesises cannot fully occur after the closing of the cranial bones in adulthood.To compensate for the relative loss of blood in the brain, she hypothesised that humans developed an internal system of control of blood flow in the brain, which Feilding identifies with the development of the "ego" and the origins of language.Trepanation, Feilding hypothesises, allows increased blood circulation, allowing people to achieve and sustain a slightly higher state of consciousness that she theorises children experience before their cranial bones fuse.