Our distant cousins, the Neanderthals, get no respect. We portray them as stocky, cave-dwelling hunter-gatherers that survived most of the last ice age only to go extinct 28,000 years ago. In 2011, Sarah Palin called Rick Santorum a "knuckle dragging Neanderthal" during the Republican presidential primary race. Her insult reflected a popular meme: Neanderthals were inferior to humans physically and cognitively.
Palin could not have been more wrong. First, if Neanderthals existed today, you could dress them with clothes from the mall. Dragging knuckles on the ground would have been no easier for them than it is for you and I. Anatomy aside, I want to challenge the conventional wisdom that Neanderthals were cognitively inferior to modern humans. I believe Neanderthals were superior to us in native cognitive aptitude and so were archaic Homo sapiens. Not only are our brains smaller than theirs, but our brains are shrinking and we are becoming dumber.
Measuring Intelligence
There are many ways to compare the cognitive ability of one individual with another. Intelligence Quotient (IQ) and g factor reduce all cognitive abilities (attention, creativity, working memory, metacognition, retrieval, etc.) to a single number. In doing so, they blur any distinction between diverse forms of cognition and their individual strengths and weaknesses. Both IQ and g factor rely on language and verbal ability (and so, also culture). IQ and g factor simplify the measure of intelligence to a point of being meaningless and it does so with a cultural and anthropocentric bias. Not that it matters in our discussion here: there are no extant Neanderthals remaining to quiz. So we need some other way to measure intelligence.
There are other ways to compare the intelligence of modern and archaic humans:
Brain size. Other things being equal, a bigger brain is better.
Persistence of a Species. The survival of a species over a long period speaks to its ability to adapt—a principal goal of intelligence.
Working memory capacity. A larger working memory supports more complex problem solving.
Behavioral complexity. We can infer much from what Neanderthals did and also from what they lacked.
Individually, these alternative measures of intelligence are speculative and evidential. Collectively, they can provide a believable and consistent story. Let's see how Homo neanderthalis stacks up to ourselves.
Brain Size
Elephants and whales have larger brains than we do. But are they smarter? Much of that size difference is because of a greater number of sensory and motor nerves. Bigger bodies with bigger muscles require more nerves to innervate them and more nerves require larger brains. So brain size alone cannot determine that one animal is smarter than the other. But if everything else is equal (same size, same Genus), a bigger brain could mean more intelligence.
To determine the brain size of our ancestors, paleoneurologists measure the volume of their exhumed skulls. Neanderthals and early humans had bigger brains than modern humans, despite having similar body sizes.
Homo heidelbergensis, 800,000 years ago: 1200 cubic centimeters
Homo neanderthalis, 28,000 years ago: 1500 cubic centimeters
Archaic Homo sapiens, 50,000 years ago: 1464 cubic centimeters
Modern Homo sapiens: 1308 cubic centimeters
We can make two observations. First, extant humans do not have the largest brain among other Homo species. Second, our brains are getting smaller [1].
Persistence of a Species
Fossil records show that 1) mammal species exist for an average of 1 million years and 2) there can be significant climate change in any million year span. A long-lasting species has faced many environmental changes and adapted to them.. Intelligence—comprising innate and learned behavior—is nature's way of adapting to change. Since we are talking about a single species here, we can assume that a species' ability to adapt over time is due primarily to learned behaviors and not genetically determined behaviors. That is why a species’ span of existence can function as a rough proxy (other things being equal) for the level of intelligence.
Within the Homo genus, Homo erectus has persisted the longest at 1.9 million years. Neanderthals lived from 400,000 to 28,000 years ago. So far, Homo sapiens have existed on this earth for less than 300,000 years - far less than Homo erectus. We might survive as a species longer than Neanderthals did, but only if we survive another 75,000 years. The chances for Homo sapiens surviving another 100 years are not assured in this age of weapons of mass destruction, dysfunctional governments, dwindling natural resources, environmental destruction, and profit-driven spread of disinformation.
Since Homo sapiens are not extinct, we cannot draw any comparison with other extinct species regarding the persistence of a species. However, it is quite possible that Homo sapiens could become the least persistent species of the dominant Homo geneses.
Working Memory Capacity
If I asked you to add 27 and 58 mentally, you'd need to remember the numbers, the sum of each column, and the carry from the one's column. Writing the two numbers down would make the task easier because then you would not need to remember the addends. Summing 32495 and 43925 in your head (without a visual refresh) becomes a more challenging. It would challenge me to remember the second number, much less five partial sums and four carries. These two mental tasks are identical processes, but they differ in the size of the working memory required to complete the task.
Working memory is an active area of research with little consensus. Some neuropsychologists are trying to locate working memory in the brain. Others question if working memory even has a location. Psychologists have developed tests for working memory that correlate very well with cognitive performance. In fact, working memory skills at 5 years of age are a better predictor of academic performance 6 years later than IQ [2].
Can working memory be determined by looking at cognitive performance? That's what paleoneurobiologists are asking. The researchers examined how early humans made stone tools and inferred working memory from the complexity of the task. They mapped increasing complexity of the Lomekwi, Oldowan, Acheulean, and Levallois stone building techniques into working memory estimates. I summarize their results in the table below. Note that MWM stands for Miller Working Memory.
In this measure of cognitive ability, Homo sapiens have the advantage.
Note: Neanderthals are not ancestors of extant humans. Homo heidelbergensis is the last common ancestor for both Homo neanderthalis and Homo sapiens. MWM stands for Miller Working Memory, one of several working memory measures.
Behavioral Complexity
We often portray early humans as primitive, less knowledgeable versions of modern humans. And why not? There were no cell phones or Internet 300,000 years ago. But life was difficult and early humans did not evolve large, energy-demanding brains for no reason. What behavior could require such a large brain?
If I were to drop you into the middle of a Europe of 300,000 years ago, do you think you could survive? We may never answer that question, but Joseph Henrich [4] comes close. He describes several 19th century expeditions led by university-trained Westerners. In each case, they explored wildernesses occupied by hunter-gatherers and their own exploration parties ran out of food. These explorers either starved to death or were saved by indigenous people. In every case, the same food sources that fed local indigenous people were available to the expedition. Because they didn't know how to prepare local food safely, some explorers got sick. Western explorers underestimated how much local knowledge they needed to survive.
Food preparation illustrates how incredibly sophisticated archaic technology was [5]. One example of archaic food preparation technology is cassava. It is a root first domesticated in South America 10,000 years ago and now a staple around the world. If it is not prepared carefully, cassava can cause acute cyanide intoxication, goiter, ataxia, partial paralysis, or death. The process used by the indigenous Tukanoans of the Colombia jungle to make cassava safe is as elaborate as making modern pharmaceuticals.
Besides cultural arrogance, we falsely presume to be smarter than early humans because we confuse knowing a fact with knowing how to find a fact. Having access to Google and Wikipedia may make me feel smart, but it is not the same as internalizing knowledge. A lot of my knowledge exists externally as notes, books, computers, and the Internet—and not in my brain’s memory anymore. It wasn’t always that way.
Do you think you could memorize a book-length poem and recite it word for word? Your ancestors could. Socrates (469-399 BCE) was a Greek philosopher who wrote none of his thoughts down but, thankfully, his student Plato (428–347 BCE) did. The following are Socrates’ comments, as transcribed by Plato. Socrates is directing his comments to the presumed inventor of writing:
"For this invention will produce forgetfulness in the minds of those who learn to use it, because they will not practice their memory. Their trust in writing, produced by external characters which are no part of themselves, will discourage the use of their own memory within them. You have invented an elixir not of memory, but of reminding; and you offer your pupils the appearance of wisdom, not true wisdom, for they will read many things without instruction and will therefore seem to know many things, when they are mostly ignorant and hard to get along with, since they are not wise, but only appear wise." [6]
Perhaps you’ve noticed your navigation skills wane when you learned to use GPS navigation applications on your phone or in your car. Likewise, you may depend more on spell checkers, grammar checkers, list managers, or other memory aids other than trusting your own memory. I know I do. This is what Socrates was talking about. The parents of children glued to a television set (the original "plug-in drug") or cell phone would echo Socrates’ concerns much later.
Poets memorized and recited book-length epic poems. Homer's Iliad is a poem divided into 24 books and written in dactylic hexameter. It contains 15,693 lines of verse. How can anyone memorize all of that?
Like lyrics in songs, poets structured these epic poems into stanzas, meters, and rhymes to aid the poet in memorization and recall. It also provided the poet and listener with authentication. Rhyming, rhyme structure, stanzas, and meters are structural elements that constrain what words can appear in a song or poem. They function like error detection in digital communication: the speaker and listener both know if a rhyme or meter is off.
Combining these structural constraints with context offers some error correction. Consider the limerick: if one leaves off the last rhyming word, many listeners are still be able to infer the missing word. This also functions as a memory aid for those reciting poems from memory. Prosody insures the authenticity of poems by providing error detection and correction.
There once was a sage named Socrates,
Whose teachings were quite a shock.
He questioned the wise,
And opened their eyes,
And Plato wrote down all his ****. [7]
We find oral traditions similar to the Greeks in Africa, the Middle East, Asia, Australia, Ireland, and among native Americans. In each case, history, law, religion, and culture pass down orally to the next generation structured to ensure accuracy and verification. [8]
Humans did not invent writing until roughly five thousand years ago. So our H. sapiens ancestors would have had to memorize everything needed for survival for nearly all of their 300,000 year existence. There was also very little division of labor among hunter-gatherers. Before the emergence of agriculture in 12,000 BCE, hunter-gatherers could not produce a surplus of food to trade with and feed non-gathering specialists such as masons, blacksmiths, or soldiers. So each family unit needed to be self-sufficient and competent in cooking, preserving food, clothing, shelters, fire maintenance, defense, hunting, plant identification for food and medicine, teaching, and more. We should be amazed by our prehistoric ancestors who had to memorize and learn so much just to survive and then to pass this knowledge on to their children.
Early humans and Neanderthals needed large brains because they needed to memorize a lot more survival knowledge than we require today. Their survival depended on a large body of locally adaptive, culturally transmitted information that no single person or group could invent within a single lifetime, yet each family unit needed to gain all of it because subject domain experts did not exist. This knowledge of the ages could only be handed down from one generation to the next orally…without the benefit of writing.
Recall that something is easier to recall if it triggers memories of different modalities. That is why prosody and rhyme aid in the recall of a poem. Yet another modality is pitch in melody. I suspect—though I cannot prove it—that every Neanderthal and archaic human sang lyrics to music because it simplified the memorization and transfer of knowledge. How far we have come when the President of the United States cannot recall the words to the national anthem?
Dumb and dumber
We are like trust fund babies who mistake unearned wealth and privilege for talent and self-esteem. Instead of inheriting money, many humans inherit cultures rich in cognitive affordances provided by those that came before us. You and I did not invent the first written language, printing presses, GPS satellites, or the Internet, but we benefit from them. These marvels of science and engineering do not increase our innate cognitive faculty any more than a trust fund makes a rich kid inherently smarter or more virtuous. Quite the opposite may occur. Some trust fund babies grow up spoiled, irresponsible, and conceited because of an inflated self-image that comes from their endowment. Likewise, our inheritance of cognitive crutches makes us feel smarter, though it means that we no longer require as large and energy-demanding a brain as we once did. The fossil record shows this to be the case, and the trend is likely to speed up as we embed computers more intimately into our lives.
We should feel humbly grateful for the technological and cultural gifts of our ancestors. This unearned gift can make some people feel superior to others with different endowments. We can make fun of Neanderthals, but they were probably innately smarter than we are today. Without a doubt, they were less dependent on cognitive crutches than we are today. We should also be grateful that many of us carry their genes within us.
[1] Stibel JM. Decreases in Brain Size and Encephalization in Anatomically Modern Humans. Brain Behav Evol. 2021;96(2):64-77. doi: 10.1159/000519504. Epub 2021 Oct 29. PMID: 34718234.
[2] Alloway, T.P., Alloway, R.G., 2010. Investigating the predictive roles of working memory and IQ in academic attainment. J. Exp. Child Psychol. 106, 20–29. https://doi.org/10.1016/j.jecp.2009.11.003.
[3] Read, D. W., Manrique, H. M., & Walker, M. J. (2022). On the working memory of humans and great apes: Strikingly similar or remarkably different? Neuroscience & Biobehavioral Reviews, 134, 104496. https://doi.org/10.1016/j.neubiorev.2021.12.019
[4] The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter. By Joseph Henrich. Princeton (New Jersey): Princeton University Press. ISBN: 978-0-691-16685-8. 2016.
[5] Ibid.
[6] Plato’s Phaedrus 275a-b. Plato in Twelve Volumes, Vol. 9 translated by Harold N. Fowler. Cambridge, MA, Harvard University Press; London, William Heinemann Ltd. 1925.
[7] Bard, Google AI. "Limerick about Socrates and Plato." Bard, Google AI, 2023-09-23. Generated and accessed 2023-09-23. The missing word is "talk".
[8] Wikipedia, "Oral tradition", en.wikipedia.org/wiki/Oral_tradition, Accessed 2023-09-23.
Author note: This article synthesizes and summarizes a lot of research. As a result, I left out many details and references. For a more in-depth treatment and more comprehensive reference list, please buy my book. If you subscribe to my Substack, Intelligence Evolved, you will be the first to know when the book is available for purchase.