In their paper Identifying hallmarks of consciousness in non-mammalian species (2005), Edelman, Baars, and Seth put forth the idea that research on consciousness needs to expand beyond methodologies which rely solely on the ability of organism somehow report their concious awareness of something (that is, behavioral tests) and encompass neuroanatomical and neurophysiological investigation. To my delight, they chose to focus on birds and octopuses as examples of animals whose possible consciousness might be probed via non-traditional methods of inquiry.
Citing evidence related the neuroanatomical and functional bases of consciousness in humans and other mammals, the authors eventually conclude that it there is a good case for avian consciousness, and the possibility of cepahlopod consciousness, based on the presence or uncertainty of these three necessary criteria:
(1) identification of neural structures that are the functional equivalents
of cortex and thalamus;
(2) neural dynamics analogous to those observed in mammals during
(3) rich discriminatory behavior that suggests a recursive linkage
between perceptual states and memory
I like their style and their argument. However, I really wanted to write about this paper for a much simpler reason. It has one of the best concluding figures that I have ever seen in a paper: