Did language drive society or vice versa?

Originally published 9 May 2000

Here’s a sen­tence from a report on the evo­lu­tion of lan­guage in a [2000] issue of Nature:

“A chal­lenge for evo­lu­tion­ary biol­o­gy, there­fore, is to pro­vide a detailed math­e­mat­i­cal account of how nat­ur­al selec­tion can enable the emer­gence of human lan­guage from ani­mal communication.”

A love­ly, com­plex sen­tence of the kind we used to dia­gram in high school.

I doubt if kids dia­gram sen­tences any more, but I loved dia­gram­ming. If noth­ing else, it gave us a sense of how a man­age­able num­ber of gram­mat­i­cal rules (syn­tax) could give rise to an end­less vari­ety of communications.

What a thing is lan­guage. Start with a bunch of nois­es — vow­els and con­so­nants; three or four dozen will do nice­ly. String them togeth­er into words and you have enough com­bi­na­tions to have a ver­bal expres­sion for mil­lions of dif­fer­ent peo­ple, places, things, and actions. A babe is born into the world know­ing nary a word. By age 2, she will have a few hun­dred words at her com­mand. An adult might have a work­ing vocab­u­lary of tens of thou­sands of words.

But even then, we don’t go around grunt­ing sin­gle words. We put words togeth­er into mean­ing­ful sen­tences using the rules of syn­tax. And sud­den­ly the num­ber of pos­si­ble utter­ances becomes essen­tial­ly infi­nite. Hop on Pop is a pos­si­bil­i­ty. So is the Holy Bible or Finnegans Wake.

Where did it all come from? When and where did lan­guage evolve? Chimps and gray par­rots can be taught to com­mu­ni­cate in a pared-down ver­sion of human lan­guage, but the dif­fer­ence between human speech and the most sophis­ti­cat­ed nat­ur­al ani­mal com­mu­ni­ca­tion is as dif­fer­ent as day and night.

No ani­mal com­mu­ni­ca­tion except our own is syn­tac­tic, or so it seems. The ter­ri­to­r­i­al calls of birds, the wig­gle dance of bees, and the mys­te­ri­ous vocal­iza­tions of whales and dol­phins are the best we get in non-human nature. Yet the lan­guage of even the most “prim­i­tive” human cul­ture is as com­plex as mod­ern Eng­lish. Clear­ly, lan­guage took a big leap for­ward as the human brain explod­ed in size and com­plex­i­ty. Like all humans on the plan­et, all spo­ken tongues can be traced back to a com­mon source.

The fact that all human lan­guages have gram­mat­i­cal sim­i­lar­i­ties sug­gests, as Chom­sky observed, an innate cor­re­spon­dence between lan­guage and the brain. But whether the acqui­si­tion of lan­guage drove devel­op­ment of the brain, or a big­ger, more com­plex brain was a pre­req­ui­site for syn­tac­tic lan­guage is a ques­tion no one can yet answer.

Can lan­guage be explained in evo­lu­tion­ary terms? That’s the ques­tion asked by Mar­tin Nowak, Joshua Plotkin, and Vin­cent Jansen in the Nature arti­cle. Their method is math­e­mat­i­cal but their con­clu­sion is sim­ple: Nat­ur­al selec­tion will favor the devel­op­ment of syn­tac­tic com­mu­ni­ca­tion when the num­ber of “rel­e­vant com­mu­ni­ca­tion top­ics” sur­pass­es a cer­tain min­i­mum number.

By “rel­e­vant com­mu­ni­ca­tion top­ics” the researchers mean any­thing in a speak­er’s envi­ron­ment that con­fers a sur­vival advan­tage if you can talk about it. “The lion is lurk­ing in the grass” might be such a mes­sage, and it is easy to see how accu­rate com­mu­ni­ca­tion of this mes­sage would give the speak­er and his lis­ten­er an edge.

But what made our hominid ances­tors’ envi­ron­ment more com­plex — more “rel­e­vant com­mu­ni­ca­tion top­ics” — than that of jack­als, dol­phins, or gray par­rots? Sure­ly oth­er species expe­ri­ence just as many threats to sur­vival, maybe more. Our authors say: “Pre­sum­ably the increase in the num­ber of rel­e­vant com­mu­ni­ca­tion top­ics was caused by changes in the social struc­ture.” Which seems to say exact­ly noth­ing by way of expla­na­tion. We are right back to the chick­en and the egg: Did lan­guage dri­ve social struc­ture or was it the oth­er way around?

Nowak, Plotkin, and Jansen show how syn­tac­tic lan­guage might have evolved, but we are left with the mys­tery of why it evolved (pre­sum­ably) unique­ly for the human species. Some­thing tru­ly won­der­ful hap­pened in the East African grass­lands a few mil­lion years ago — the appear­ance of big, com­plex brains artic­u­lat­ing a sophis­ti­cat­ed reper­toire of com­bi­na­to­r­i­al sounds — and it seems to have hap­pened all of a piece.

It is easy enough to under­stand the evo­lu­tion­ary pres­sures that caused our ances­tors to say “The lion is lurk­ing in the grass” or “There’s a nice source of flinty stones just beyond the hill,” but where, for heav­en’s sake, did “The sun­set is beau­ti­ful” come from? And what dynam­ic of nat­ur­al selec­tion con­ferred upon one species among all the oth­ers the abil­i­ty to say:

She walks in beauty, like the night
Of cloudless climes and starry skies,
And all that's best of dark and bright
Meet in her aspect and her eyes?