Well, clearly we're special enough to take over the world. I'm not sure how we can be sure that chimps or dolphins don't have something that could be called introspection. (That's partially an expression of my opinion and partly of my personal ignorance - I welcome enlightenment on the topic.)
I wonder when and how we started time-binding.
Following The Rational Optimist by Matt Ridley and many other sources, I suspect the dominating differences between chimps and us is abilities we have evolved that greatly enhance the effectiveness of our working together in large groups. The more you enable cooperation, the more things like complex language and cognition suitable for highly specialized (i.e. a specialized cog in a larger machine) production.
It seems to me that introspection is valuable even in a non-cooperative world: if I can fine tune my reactions to prey and my attractiveness to the...
The Francis Crick Memorial Conference, held in Cambridge last month, has come up with the Cambridge Declaration on Consciousness (PDF).
tl;dr humans still aren't special, consciousness seems to arise in quite a variety of nervous systems and working out what it is is a problem in neurology.
We declare the following: “The absence of a neocortex does not appear to preclude an organism from
experiencing affective states. Convergent evidence indicates that non-human animals have the
neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with
the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that
humans are not unique in possessing the neurological substrates that generate consciousness. Non-
human animals, including all mammals and birds, and many other creatures, including octopuses, also
possess these neurological substrates.”