Really just an excuse to use the headline above, I link to this story on the possible consciousness of cephalopods :

The problem with measuring something like “consciousness” is that there is no agreed-upon definition. However, scientists can use a few basic tools to determine whether animals think in ways that humans would recognize as similar to themselves. You can measure (to a certain degree) whether a creature has self-awareness, independent problem-solving abilities, and exhibits brain activities that resemble “thinking” in the human brain.