Homo Sapien's Success

In “The Most Invasive Species of All,” Curtis W. Marean includes a fanciful image of Neandertals telling boastful tales around their campfires. While this was clearly meant as a literary device, it points out a serious oversight: he left speech out of his list of current theories of why humans came to dominate the planet. And his few references to language imply that he believes speech was equally available to all human groups.

There is no scientific consensus for that, and based on anatomical differences, some researchers think speech was the key advantage modern humans had over the Neandertals. Indeed, it is hard to credit the level of cooperation Marean calls “hyperprosociality” and attributes as key to Homo sapiens' success as possible without speech.

Mountain View, Calif.

There is a questionable idea, which Marean seems to take for granted, that human success all comes down to better and better spearpoints and male activities. Why are all the allegedly successful attributes of our species male ones? It may have escaped his notice that virtually every aspect of human replication is determined by women. And according to some authors the act of gathering can provide more protein than hunting. The plentiful beds of shellfish Marean argues were highly important to human evolution would have been gathered, not hunted.

Bendigo, Australia

MAREAN REPLIES: On the issue of speech and language: I agree that the highly advanced hyperprosocial behavior exhibited by modern humans requires a reasonably advanced form of communication. We know that fully modern speech must have existed before 110,000 years ago because that is when the oldest surviving human lineage (the Khoisan peoples) originated, and that group has a fully modern language. There have been some estimates that language is as old as the shared common ancestor of modern humans and Neandertals. There is no consensus that Neandertals lacked the anatomical machinery for speech—we just do not have the relevant parts preserved.

Regarding Verrinder's objection to the overtly “male-centric” theme of my article: it is a sequel to my 2010 Scientific American article “When the Sea Saved Humanity,” in which I emphasized the importance of shellfish and plant collection to the survival of our species. The ethnographic record clearly shows that in hunter-gatherer societies, those two activities are typically the work of women. The 2010 article was about how food and shared ingenuity helped our species survive through a climate crisis, but the topic of the current article is what happens when one ethnolinguistic group invades the territory of another. Such events are penetrating, brutal, bloody affairs, and the killing and butchery that ensue is the product of weapons and men.

Save our hearing

In “Hidden Hearing Loss,” M. Charles Liberman describes how elevated noise levels can permanently damage auditory nerve fibers. As a doctor and a member of the board of the American Tinnitus Association, I can say that Liberman's work and thousands of peer-reviewed articles have established that noise is a hazard for hearing and general health.

In the 1950s, when the medical and scientific communities became aware that smoking caused cancer and heart disease, they spoke out about it and spearheaded antismoking efforts. Such efforts eventually led to one of the great public health successes of the last quarter of the 20th century: a marked decrease in smoking and our essentially smoke-free environment. It is time for a similar effort to make our environment quieter before we are all deaf.

Beverly Hills, Calif.

Spaceflight rhetoric

In “Space Cowboys” [Forum], Linda Billings complains that the rhetoric about space exploration in the U.S. is colonialist and marginalizes women, minorities and non-Americans.

It is true that colonialist attitudes, applied within the confines of Earth, have been very damaging. But in the realm of space exploration, who stands to be exploited? The “conception of outer space as a place of wide-open spaces and limitless resources” she criticizes is completely accurate. By encouraging support for space exploration with such frontier imagery, we can reap benefits for the species as a whole.

Her proposition that a rhetoric of exploration would appeal only to white American males is also objectionable. As a non-American female science student, a frontier is exactly how I view space, and such language is engaging to me.

Hamilton, Ontario

Benefits of testing

I was interested in reading about the way retrieval practice, in which testing is used to reinforce learning rather than assess it, was being used in the classroom in “A New Vision for Testing,” by Annie Murphy Paul [Building the 21st-Century Learner]. A variation of this learning has been growing in popularity among many language learners for years now, with many using flashcard programs to employ “spaced repetition,” in which the time periods between learning and reviewing material increase.

Traditional teaching tends to place more onus on learners to find a way to absorb the material themselves than it does on the teacher in helping them. It is also important to empower students with a method for studying at home using a framework such as retrieval practice.

Glasgow, Scotland

I recall that in the 1950s and 1960s, we learned using many of the same methods as are used in “retrieval practice”: weekly quizzes discussed in recitations and labs, problem sets that had to be turned in and discussed in class, end-of-chapter questions in textbooks that were handed back with corrections. That system seemed to have worked quite well in producing scientists and engineers of my generation.

University of Rhode Island

Gun control

I was disappointed that the editors decided to wade into the controversy over doctors questioning patients about gun ownership in “Docs, Glocks and Stray Bullets” [Science Agenda]. Does anyone believe that a doctor who does not even own a gun can advise on handgun safety? Doctors should stick to their area of expertise.


The right to have a gun is an anathema to most of us outside the U.S. The level of gun deaths—murders, suicides and accidents—shows that allowing citizens to own them is bad for society. To silence doctors on this subject is incomprehensible. Not to have an ownership database is astonishing.

via e-mail


“Hidden Hearing Loss,” by M. Charles Liberman, incorrectly refers to correcting myopia by laser surgery of the lens. Such surgery is performed on the cornea.