From an evolutionary perspective, fears and anxieties surrounding being left alone at night are entirely normal and actually important. This innate fear would have kept our offspring safe, at a time when they would have been most at risk if left alone. While life has changed immeasurably as our species has evolved, this natural fear has not moved with the times. We know our children are safe from predators, warm, dry and comfortable tucked up in their beds at night and so do our children, when you hold a rational conversation with them that is. Their instincts and psyche often says otherwise though.
Sarah Ockwell-Smith 