This is a Freakonomics guest post by Mark Changizi, an evolutionary neurobiologist, and Director of Human Cognition at 2AI. His new book Harnessed explores the evolutionary origins of language and music.
Rise of the Apes via Miracle Grow
By Mark Changizi
Add Miracle Grow to your tomato plants and you get tomatoes. Big tomatoes, but still tomatoes. What you don’t get are mobile, blood-thirsty tomatoes with a deep distaste for the classic tune, “Puberty Love.” That would require serious evolutionary design, something far more complex than Miracle Grow can handle.
Yet something very much like Miracle Grow works for giving chimps and gorillas human-level intelligence. Or, at least, that’s what you’d have to believe to accept the premise of the summer movie, Rise of the Planet of the Apes, where a grow-more-neurons drug aimed for Alzheimers is given to apes, who thereby become the cognitive equal of humans, replete with language.
Obviously, that can’t happen. Our human brain is not simply a bigger version of the same fundamental ape design. Rather, it possesses essential new software forged over millions of years of natural selection. Some believe there is new language software, a language instinct; while others believe, in contrast, that what’s new are general-purpose algorithms of the kind artificial intelligence researchers seek. A simple give-‘em-more-neurons mechanism can’t reproduce these sorts of designs.
And so, for those of us inclined to get testy about the science in movies, Rise of the Planet of the Apes stands on scientific quicksand.
Or does it?
As if timed for co-release, my new book, Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man, hit bookstores the same week that Rise of the Planet of the Apes hit theaters. My book is about the first rise of the planet of the apes – how those Homo sapiens apes became the humans we take ourselves to be today – and it implicitly provides a scientific justification for the fictional next rise in the movie. In my view, based on my research, Miracle Grow is all you need to turn our “lower” cousins into our equals.
In Harnessed I argue that the qualitative difference between us and the other apes isn’t in our brains or genes. Instead, it’s all in culture. Our Homo sapiens ancestors had at one time no language or arts, despite having our brains and genomes. But at some point, a new kind of design-by-evolution got under way: cultural evolution.
Cultural selection can create brilliantly designed artifacts, designed for our minds. And it can do so at much faster time scales than natural selection.
Writing, speech and music – the core artifacts underlying much of what we believe qualitatively differentiates us from our ape relatives – have culturally evolved to have shapes that the brain is good at processing. These cultural artifacts harness us. Or, as eminent scientist and author of Reading in the Brain Stanislas Dehaene says, culture engages in “neuronal recycling.”
What’s new about my research and book is that I have a specific theory about culture’s special trick for harnessing us. I call it “nature-harnessing” – the core artifacts of writing, speech and music have come to be shaped like fundamental aspects of nature, just the sort of stimulus structure the ancient illiterate, non-language, amusical ape brain is brilliantly able to process.
How does one show that writing, speech and music are structured “like nature”? And, what could that even mean?
The strategy is to identify regularities in the structure of natural stimuli, and show that we find the same regularities in the structure of the cultural artifacts that harness the brain regions for those natural stimuli.
So, how can we read? Terrestrial worlds like ours are populated with opaque objects strewn about in three-dimensional space. One can work out that certain conglomerations of contours happen in such worlds, and other conglomerations do not. Question is: does writing across humankind glom onto these worldly conglomerations? The answer is, Yes – something I found by examining more than one hundred writing systems over history.
And we comprehend speech because, I argue, speech has been culturally selected to sound like the most fundamental sounds in terrestrial habitats – solid-object events. The “grammar” found among the hits, slides, and rings of solid-object events is found among the plosives (like b, t), fricatives (like f, v) and sonorants (like vowels, and phonemes like y, w, r, l) of speech.
Finally, I argue that music has the signature structure found in the sounds that people make when they move and carry out expressive bodily behaviors. The rhythm, melody, and loudness regularities of music are found in the gait, Doppler-shifts, and distance modulations of the human movers around you in the world. The sounds we make when we move have a tremendous amount of structure, and I’ve provided case after case where this signature structure is also found in music. Music is a fictional story of a person moving expressively in your midst, which is why music is evocative; but speech sounds are not. (In this light, dance is simply a case where you are moving with this fictional mover. That is, why should an auditory stimulus possibly evoke a drive to move in time to it? Because the stimulus is the sound of movement – the sound of the “dance” itself.)
Thus, in the framework I defend in Harnessed, the real code that matters in explaining who we humans are today is not the genome or the neural code, but the nature-mimicking code that has been hiding all along within the structure of our most dear artifacts.
And it follows that the solid-object event sounds of human speech harness chimp and gorilla ears as well. Our writing, too, harnesses their visual object-recognition system.
On the comprehension side then, all the apes in Rise of the Planet of the Apes need in order to process human language is quantitatively more brain power, a role filled by the fictional Alzheimer drug. Giving them more neurons suffices!
And now you are prepared to enjoy the movie, science-nagger-free.