What makes us human?

What makes us human?

A facial reconstruction of Homo floresiensis • Cicero Moraes et al (CC BY 4.0)

Originally published 14 November 2004

About fifty years ago, a “stone age” tribe was dis­cov­ered liv­ing in an iso­lat­ed val­ley of Papua New Guinea. These peo­ple had vir­tu­al­ly no con­tact with the out­side world, no met­al, no cook­ing ves­sels, no hearths. They lived pret­ty much as all humans had lived tens of thou­sands of years ago, before the dis­cov­ery of met­als and inten­sive agriculture.

Nev­er­the­less, these abo­rig­i­nal New Guineans are ful­ly mem­bers of the species Homo sapi­ens. They have art, lan­guage, and com­plex cog­ni­tive and emo­tion­al lives. They can inter­breed with the rest of us.

I dare say that today these peo­ple are watch­ing satel­lite tele­vi­sion and wear­ing New York Yan­kee tee shirts. For all I know one of their tribe is attend­ing uni­ver­si­ty at NYU.

Now imag­ine if the peo­ple dis­cov­ered in that remote val­ley were not exact­ly human. Imag­ine instead a dif­fer­ent species of human­like crea­tures about one meter tall, with a brain the size of a chim­panzee’s. These lit­tle peo­ple walk erect. Their anato­my is more human­like than chim­p­like. They fash­ion stone tools. And they are smart enough to have made their way by raft to New Guinea from the Asian mainland.

In short, these new­ly dis­cov­ered crea­tures are part of the genus Homo, but a dif­fer­ent species from our­selves. They are a sec­ond, non-inter­breed­ing branch on the human fam­i­ly tree.

How would we treat these tiny, less brainy ver­sions of our­selves? Would we put them in zoos, or extend them human rights? We would sure­ly want to know if they have the pow­ers of speech, abstract art, esthet­ic expres­sion. Do they won­der at the star­ry night? Make orna­ments for their bod­ies? Bury their dead?

What­ev­er the answers, dis­cov­ery of a sec­ond liv­ing species of humans would be head­line news around the world.

As it turns out, such a dis­cov­ery might have been pos­si­ble. As report­ed in a [2004] issue of Nature, anthro­pol­o­gists have found the skele­ton (not yet fos­silized) of just such a crea­ture in a cave on the island of Flo­res in east­ern Indone­sia, a place nev­er con­nect­ed by land to Asia.

The bones, believed to be those of a female, are about 18,000 years old. Oth­er scat­tered bones indi­cate that some of her species were alive even lat­er, per­haps as the first urban civ­i­liza­tions were devel­op­ing in the Mid­dle East about 12,000 years ago. It is remote­ly pos­si­ble that some rem­nant pop­u­la­tion of Homo flo­re­sien­sis (as the species is called) lingers even today, on some iso­lat­ed island of the Indone­sian archipelago.

Homo flo­re­sien­sis is not the first species of human known to over­lap with our own. Nean­derthals diverged from our com­mon ances­tral stock about half a mil­lion years ago and shared parts of the plan­et with us until they became extinct about 30,000 years ago. Homo flo­re­sien­sis appears close­ly relat­ed to Homo erec­tus, which branched from our ances­tral fam­i­ly tree about a mil­lion years ago.

How did Homo sapi­ens inter­act with this oth­er species who for so long shared our space? Were we the cause of their extinc­tion? Per­haps Homo flo­re­sien­sis did­n’t raft to Flo­res on their own; per­haps they were car­ried there as a sort of domes­ti­cat­ed com­pan­ion by our own kind of humans, which reached Aus­tralia 40,000 years ago.

One can be sure that anthro­pol­o­gists from around the world will now be rush­ing to the Indone­sian islands to look for sup­port­ing evi­dence of this star­tling new dis­cov­ery. One skele­ton implies more, and the fact that the skele­ton is so recent means that oth­ers might not be so dif­fi­cult to find.

The new dis­cov­er­ies — and they will come — will fix our own species ever more firm­ly in the tree of life, and require us to rethink what it is that makes us special.

Is it the size of our brains that defines our unique human­i­ty? Lan­guage? Tool­mak­ing? Art? Or is it our capac­i­ty to embrace com­plex­i­ty, to be curi­ous about our ori­gins, to live in the future rather than the past.

The unfor­tu­nate Flo­re­sians, who lived so recent­ly, may have been vic­tims of our own ani­mal vio­lence. The anthro­pol­o­gist Mar­garet Mead once said that the progress of civ­i­liza­tion is the ever widen­ing cir­cle of those whom we do not kill. Per­haps our most dis­tin­guish­ing char­ac­ter­is­tic as a species is that if we came upon a rem­nant tribe of Flo­re­sians today, we might pro­tect them rather than destroy.

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