The declaration, called The Cambridge Declaration On Consciousness, was signed at the Francis Crick Memorial Conference of Consciousness in Human and Non-Human Animals in the presence of Stephen Hawking in July in Cambridge, U.K. by an international group of scientists including cognitive neuroscientists, neuropharmacologists, neurophysiologists, neuroanatomists and computational neuroscientists.

What do they mean by consciousness? The Declaration treats it as the same as the phrase, "subjective experience." Philosophers who share this view of consciousness with the scientists often say that something is conscious if there is "something that it is like" to be that thing. So, according to this, a rock is not conscious, because there is nothing "that it is like to be a rock."

The signing marked the first formalization of the scientific consensus about the consciousness of several non-mammals, including birds, octopuses and even bees.

Octopuses are a remarkable addition to this list, not only because they are the only invertebrate included, but also because the way their brain evolution has progressed is so dissimilar from humans. The most notable dissimilarity is the lack of the neocortex that was long believed to be the biological foundation of human conscious experience.

The bases for the assertions of consciousness are, condensed, that:

1) "The neural substrates of emotions do not appear to be confined to cortical structures." This means that animals with brains which have evolved differently from or less than humans can experience brain states that are "rewarding and punishing."