Thinking animals
An interesting article, but the question of human consciousness seems no closer to solution in “Humans wonder, anybody home?” by Susan Gaidos (SN: 12/19/09, p. 22) than it did in Julian Jaynes’ The Origin of Consciousness in the Breakdown of the Bicameral Mind of 1976. It seems to me that all the mental abilities discussed do not show that humans can do something unique to our species, or show that we are more “conscious” than other species, but only that species display varying degrees of ability. For example, humans are not the only animals to make tools, we just make better ones.
But what I’ve never seen investigated (except in Jaynes’ book) is the one attribute that seems uniquely human. Most animals appear interested in the answers to “What is it?” “Who is it?” “Where is it?” and even “When is it?” It also seems clear that many species are working on the question “How?” as when the crow learns to make a hook. But where is the evidence that any other species has ever asked “Why?”
Richard S. Blake, East Falmouth, Mass.

In the article “Humans wonder, anybody home?” the author states (Page 25): “Octopuses share one brain trait with mammals and birds: They have a high brain-to-body mass ratio.”
However, considering the visual plot (Page 24) showing brain weight as a function of body weight for various species, the octopus has one of the lowest brain-to-body mass ratios of all the species shown.
Am I reading the plot incorrectly or is there a disconnect between the plot and the text in the article? If I am interpreting the plot correctly as showing that the octopus has a low brain-to-body mass ratio, why is it that “octopuses do seem to be one of the most intelligent invertebrates around”?
Jerry Kerrisk, Santa Fe, N.M.

The octopus’s brain-to-body mass ratio is lower than that of most mammals shown. But “mammals” is the key word. The plot is intended to convey that the octopus brain rivals that of mammals and birds, despite the fact that the octopus is an invertebrate — a group often assumed to be less intelligent. — Elizabeth Quill

Clarification : The article “Humans wonder, anybody home?” states that in 2005, Duke University neuroscientist Erich Jarvis showed that bird brains consist of more than a few primitive structures. Actually the research was compiled over several decades by neuroscientists Harvey Karten and R. Glenn Northcutt, both at the University of California, San Diego, and collaborators. In 2005, Jarvis organized a conference to formally revise the existing nomenclature for bird brains.