In several places in the book when talking about what a sentient virtual human might represent we highlight the importance of some form of inner dialogue or narrative, and introduce the topic at the end of Chapter 5. We know that animals "sense" - and so could be described as sentient, and that they can feel and show emotion, and some of them are quite clever, but we have no idea as to whether they have their own internal narrative, that second by second inner voice thinking through what to do, and that sense of a continuous life-time narrative.
One rather nice distinction is between shallow and deep consciousness, thought of in terms of time. An animal may have shallow consciousness - it can remember only a short distance into the past (apart from the longer term patterns such as migration, when an owner is home, when its dinner time etc), and probably see only a short distance into the future. Humans however have deep consciousness - the think not only backwards through almost our entire life but also backwards through the whole of human history and forwards into our own possible futures, and again the future of the whole of humanity.
Equipping a virtual human with an internal dialogue/narrative, both the short term "tactical" one and the longer term "strategic"/life-story one may well be a necessary condition of creating a truly sentient virtual human.
What is surprising though is how little this area seems to have been researched. We'll link into what papers we find below and it is likely to form an important part of our own research going forwards.