Orangutans can communicate about the past just like humans, new research finds
The evolution of language converted a defenceless naked ape into a world-dominating force. It fundamentally transformed how humans transmit information and knowledge. A large and potent component of language is our ability to communicate about things that are not here, that happened in the past, or that will happen in the future. This feature of language is known as “displaced reference”.
Displaced reference is universal across the world’s languages and pervades our daily lives. In fact, to speak about the present moment has become a rarity nowadays, though noticeable exceptions are when we comment about the weather, ask for the salt over the dinner table, or talk with very young children.
Displaced reference unshackles speakers from the present. The magnitude of information that becomes available to individuals (or species) capable of displaced reference is therefore immeasurably greater than individuals (or species) strictly living in “the here and the now” – which is the bulk of the animal kingdom.
So far, besides humans, only social insects are capable of displaced reference. It is remarkable how honey bees (and their tiny brains) can communicate, for instance, about the location of distant food sources to other bees in the hive. The discovery of this fact merited a Nobel Prize in Physiology and Medicine for Karl von Frisch in 1973. Displaced reference in social insects spawns many fascinating – and unanswered – questions about animal intelligence and what the minimal viable intelligence systems for a particular cognitive capacity are.
However, biologically, bees and other insects are far apart from humans and can tell us very little about how language evolution played out among our ancestors. Lacking examples in vertebrates, mammals, or non-human primates, including great apes – our closest relatives – scientists literally had no clues about how this capacity came about in humans. But this is the new jigsaw piece that wild orangutans are bringing to the puzzle of language evolution.
The missing link?
In the low mountain rainforests of Sumatra, Indonesia, our team simulated a natural encounter with a predator to study the vocal responses of wild orangutan females. The set up consisted of a human researcher, disguised as a forest big cat, parading on all fours across the forest floor in front of the orangutan females.
We observed that, despite showing all sorts of distress (including urinating and defecating), orangutan females refrained from responding vocally towards the “predator”. Instead, they waited up to 20 minutes to communicate their alarm to their offspring, long after the predator had left the scene. Across several experiments there was an average delay of seven minutes before the females vocally expressed their alarm.
The data (and simple common sense if we imagine ourselves facing a wild Sumatran tiger!) suggest that to respond vocally in the presence of a predator would have been a huge risk to the orangutans’ safety. If the females had responded immediately by calling out warnings, the predator could have detected them and perhaps attempted an attack, particularly on the infant orangutans.
Instead, the mothers waited for a significant amount of time before signalling vocal alarm about the danger that had now passed. The question that springs to mind, then, is: why did the females signal their alarm at all? If they hadn’t responded vocally at any point, they wouldn’t have faced any danger at all, right?
That is undoubtedly true; but had the mothers not expressed alarm, their infants would have remained oblivious to one of the most lethal dangers in the rainforest. Instead, the females waited long enough until it was safe to call out, but not so long that their infants could not connect their mothers’ vocal distress with what had just happened, and understand that it was extremely dangerous. The female orangutans were teaching their young about the dangers in the forest by referring to something that had happened in the (recent) past.
In the 1970s, early attempts to release rescued orangutans and reintroduce them back into this same forest failed miserably. Nearly all the released animals fell prey to forest cats, essentially for lack of knowledge about survival in the rainforest.
Orangutan infants stay with their mothers as long as human children do. It has been shown that this exceptionally long period ensures that mothers pass on a variety of knowledge, skills and tools to their offspring. Our new findings indicate that teaching about predators is a vital aspect of this.
Widening this out to human language evolution, orangutans exemplify how our ancestors probably communicated beyond the here-and-now about the past, and possibly the future, even before they had uttered their first word. Together with mounting evidence, great apes are helping scientists build a clearer picture of our ancient ancestors as they moved towards fully fledged language.
By showing us that we are, after all, not so different from them, great apes help us learn where we come from, define who we are and, hopefully, decide where we are going as intelligent stewards of our precious planet.
Data from 78 societies testing several predictions. Results show higher levels of aggressiveness in societies with greater intensity of male mating competition
In the UK, people in different regions vary genetically both by ancestry and by genes associated with educational attainment (EA) (and less strongly for genes related to body dimensions, personality and health). Selective migration within the country.
this is significant because it undermines an old foundation of blank slatism: that human culture takes them beyond genes, unlike animals. If even simple animals like fruit flies (let alone chimps or dolphins) have culture it challenges that dichotomy.
Widespread structural, chemical and molecular differences have been reported between the male and female human brain. Although several neurodevelopmental disorders are more commonly diagnosed in males, little is known regarding sex differences in early human brain development. Here, we used RNA sequencing data from a large collection of human brain samples from the second trimester of gestation (N = 120) to assess sex biases in gene expression within the human fetal brain. In addition to 43 genes (102 Ensembl transcripts) transcribed from the Y-chromosome in males, we detected sex differences in the expression of 2558 autosomal genes (2723 Ensembl transcripts) and 155 genes on the X-chromosome (207 Ensembl transcripts) at a false discovery rate (FDR) < 0.1. Genes exhibiting sex-biased expression in human fetal brain are enriched for high-confidence risk genes for autism and other developmental disorders. Male-biased genes are enriched for expression in neural progenitor cells, whereas female-biased genes are enriched for expression in Cajal-Retzius cells and glia. All gene- and transcript- level data are provided as an online resource (available at http://fgen.psycm.cf.ac.uk/FBSeq1) through which researchers can search, download and visualize data pertaining to sex biases in gene expression during early human brain development.
“Evolution denialism is back, but this time it’s coming from left-wing activists who do hold power in academia.”
Evolutionary biology has always been controversial. Not controversial among biologists, but controversial among the general public. This is largely because Darwin’s theory directly contradicted the supernatural accounts of human origins rooted in religious tradition and replaced them with fully natural ones. The philosopher Daniel Dennett has described evolution as a sort of “universal acid” that “eats through just about every traditional concept, and leaves in its wake a revolutionized world-view, with most of the old landmarks still recognizable, but transformed in fundamental ways.” Fearing this corrosive idea, opposition in the US to evolution mainly came from Right-wing evangelical Christians who believed God created life in its present form, as described in Genesis.
In the 1990s and 2000s there were repeated attempts by evangelicals to ban evolution in public schools or teach the so-called “controversy” by including Intelligent Design—the belief that life is too complex to have evolved without the aid of some “Intelligent Designer” (i.e. God)—in the biology curriculum alongside evolution. But these attempts failed when scientists demonstrated in court that Intelligent Design was nothing more than Biblical Creationism gussied up in scientific-sounding prose. Since then, however, Creationism and Intelligent Design have lost a tremendous amount of momentum and influence. But while these right-wing anti-evolution movements withered to irrelevancy, a much more cryptic form of left-wing evolution denialism has been slowly growing.
At first, left-wing pushback to evolution appeared largely in response to the field of human evolutionary psychology. Since Darwin, scientists have successfully applied evolutionary principles to understand the behavior of animals, often with regard to sex differences. However, when scientists began applying their knowledge of the evolutionary underpinnings of animal behavior to humans, the advancing universal acid began to threaten beliefs held sacrosanct by the Left. The group that most fervently opposed, and still opposes, evolutionary explanations for behavioral sex differences in humans were/are social justice activists. Evolutionary explanations for human behavior challenge their a priori commitment to “Blank Slate” psychology—the belief that male and female brains in humans start out identical and that all behavior, sex-linked or otherwise, is entirely the result of differences in socialization.
This stance is maintained by the belief that evolutionary explanations for sex-linked behavioral differences are biologically essentialist, which is the fatalistic notion that biology alone directly determines our behavior. Blank Slate psychology, however, is universally rejected by experts, as the evidence for innate sex-linked personality differences in humans is overwhelmingly strong. But experts also universally reject that this view demands we embrace biological essentialism, because the environment does play a role, and observed sex differences are simply averages and overlap tremendously between the sexes. Sex no more determines one’s personality than it determines one’s height. Sex certainly influences these traits, but it does not determine them. For instance, most of us know females who are taller than most males, and males who are shorter than most females, though we are all aware that males are, on average, taller than females. In humans, the same is true for behavioral traits.
I am an evolutionary behavioral ecologist, and most of my work is concerned with how individual differences in behavior (i.e. personality) influence individual fitness, and the collective behavior and success of animal societies. Most are probably not aware, but animal personality research is a vibrant field within behavioral ecology due to the ubiquity of personality as a phenomenon in nature, and its ability to explain interactions both within and between species. In nearly every species tested to date for the presence of personality, we’ve found it, and sex-linked personality differences are frequently the most striking. Sex-linked personality differences are very well documented in our closest primate relatives, too, and the presence of sexual dimorphism (i.e. size differences between males and females) in primates, and mammals generally, dramatically intensifies these differences, especially in traits like aggression, female choosiness, territoriality, grooming behavior, and parental care.
Given that humans are sexually dimorphic and exhibit many of the typical sex-linked behavioral traits that any objective observer would predict, based on the mammalian trends, the claim that our behavioral differences have arisen purely via socialization is dubious at best. For that to be true, we would have to posit that the selective forces for these traits inexplicably and uniquely vanished in just our lineage, leading to the elimination of these traits without any vestiges of their past, only to have these traits fully recapitulated in the present due to socialization. Of course, the more evidenced and straightforward explanation is that we exhibit these classic sex-linked behavioral traits because we inherited them from our closest primate ancestors.
Counterintuitively, the social justice stance on human evolution closely resembles that of the Catholic Church. The Catholic view of evolution generally accepts biological evolution for all organisms, yet holds that the human soul (however defined) had been specially created and thus has no evolutionary precursor. Similarly, the social justice view has no problem with evolutionary explanations for shaping the bodies and minds of all organisms both between and within a species regarding sex, yet insists that humans are special in that evolution has played no role in shaping observed sex-linked behavioral differences. Why the biological forces that shape all of life should be uniquely suspended for humans is unclear. What is clear is that both the Catholic Church and well-intentioned social justice activists are guilty of gerrymandering evolutionary biology to make humans special, and keep the universal acid at bay.
Despite there being zero evidence in favor of Blank Slate psychology, and a mountain of evidence to the contrary, this belief has entrenched itself within the walls of many university humanities departments where it is often taught as fact. Now, armed with what they perceive to be an indisputable truth questioned only by sexist bigots, they respond with well-practiced outrage to alternative views. This has resulted in a chilling effect that causes scientists to self-censor, lest these activists accuse them of bigotry and petition their departments for their dismissal. I’ve been privately contacted by close, like-minded colleagues warning me that my public feuds with social justice activists on social media could be occupational suicide, and that I should disengage and delete my comments immediately. My experience is anything but unique, and the problem is intensifying. Having successfully cultivated power over administrations and silenced faculty by inflicting reputational terrorism on their critics and weaponizing their own fragility and outrage, social justice activists now justifiably think there is no belief or claim too dubious that administrations won’t cater to it. Recently, this fear has been realized as social justice activists attempt to jump the epistemological shark by claiming that the very notion of biological sex, too, is a social construct.
As a biologist, it is hard to understand how anyone could believe something so outlandish. It’s a belief on a par with the belief in a flat Earth. I first saw this claim being made this year by anthropology graduate students on Facebook. At first I thought they mistyped and were simply referring to gender. But as I began to pay closer attention, it was clear that they were indeed talking about biological sex. Over the next several months it became apparent that this view was not isolated to this small friend circle, as it began cropping up all over the Internet. In support of this view, recent editorials from Scientific American—an ostensibly trustworthy, scientific, and apolitical online magazine—are often referenced. The titles read, “Sex Redefined: The Idea of 2 Sexes Is Overly Simplistic,” and “Visualizing Sex as a Spectrum.”
Even more recently, the most prestigious scientific journal in the world, Nature, published an editorial claiming that classifying people’s sex “on the basis of anatomy or genetics should be abandoned” and “has no basis in science” and that “the research and medical community now sees sex as more complex than male and female.” In the Nature article, the motive is stated clearly enough: acknowledging the reality of biological sex will “undermine efforts to reduce discrimination against transgender people and those who do not fall into the binary categories of male or female.” But while there is evidence for the fluidity of sex in many organisms, this is simply not the case in humans. We can acknowledge the existence of very rare cases in humans where sex is ambiguous, but this does not negate the reality that sex in humans is functionally binary. These editorials are nothing more than a form of politically motivated, scientific sophistry.
The formula for each of these articles is straightforward. First, they list a multitude of intersex conditions. Second, they detail the genes, hormones, and complex developmental processes leading to these conditions. And, third and finally, they throw their hands up and insist this complexity means scientists have no clue what sex really is. This is all highly misleading and deceiving (self-deceiving?), since the developmental processes involved in creating any organ are enormously complex, yet almost always produce fully functional end products. Making a hand is complicated too, but the vast majority of us end up with the functional, five-fingered variety.
What these articles leave out is the fact that the final result of sex development in humans are unambiguously male or female over 99.98 percent of the time. Thus, the claim that “2 sexes is overly simplistic” is misleading, because intersex conditions correspond to less than 0.02 percent of all births, and intersex people are not a third sex. Intersex is simply a catch-all category for sex ambiguity and/or a mismatch between sex genotype and phenotype, regardless of its etiology. Furthermore, the claim that “sex is a spectrum” is also misleading, as a spectrum implies a continuous distribution, and maybe even an amodal one (one in which no specific outcome is more likely than others). Biological sex in humans, however, is clear-cut over 99.98 percent of the time. Lastly, the claim that classifying people’s sex based on anatomy and genetics “has no basis in science” has itself no basis in reality, as any method exhibiting a predictive accuracy of over 99.98 percent would place it among the most precise methods in all the life sciences. We revise medical care practices and change world economic plans on far lower confidence than that.
Despite the unquestionable reality of biological sex in humans, social justice and trans activists continue to push this belief, and respond with outrage when challenged. Pointing out any of the above facts is now considered synonymous with transphobia. The massive social media website Twitter—the central hub for cultural discourse and debate—is now actively banning users for stating true facts about basic human biology. And biologists like myself often sit quietly, afraid to defend our own field out of fear that our decade of education followed by continued research, job searches, and the quest for tenure might be made obsolete overnight if the mob decides to target one of us for speaking up. Because of this, our objections take place almost entirely between one another in private whisper networks, despite the fact that a majority of biologists are extremely troubled by these attacks to our field by social justice activists. This is an untenable situation.
It is undoubtedly true that trans people lead very difficult lives, which are only made more difficult by the bigotry of others. But social justice activists appear completely unwilling or unable to distinguish between people who criticize their ideology and people who criticize their humanity. Their social immune system appears so sensitive that it consumes itself. We need to acknowledge that trans issues and ideology are complex, and concern one of the most marginalized communities in the world. Because of this, we must give these issues the respect they deserve by approaching them with nuance and compassion instead of crudeness and cruelty. But we must not jettison truth in this process. If social justice activists require scientists to reject evolution and the reality of biological sex to be considered good allies, then we can never be good allies.
Back when evolution was under attack from proponents of Biblical Creation and Intelligent Design, academic scientists were under no pressure to hold back criticism. This is because these anti-evolution movements were almost exclusively a product of right-wing evangelicals who held no power in academia. Now we have a much bigger problem, because evolution denialism is back, but this time it’s coming from left-wing activists who do hold power in academia. This makes the issue both harder to ignore and harder to remove. Social justice and hyper-militant trans activism now seems to act as a kind of anti-universal acid, and not merely a strong buffer solution. While the universal acid of evolution eats through old cherished beliefs and replaces them with deeper understanding and a clearer picture of reality, the anti-universal acid of social justice ideology is a recklessly destructive force, aiming to abolish scientific truth and replace it with relativistic postmodern nonsense.
I did not train to be a scientist for over a decade just to sit quietly while science in general, and my field in particular, comes under attack from activists who subvert truth to ideology and narrative. When I reflect on my initial reasons over a decade ago for choosing a career as an academic scientist, it was largely due to the inspiration I felt from outspoken public intellectuals like Richard Dawkins, Sam Harris, Stephen Fry, and the late Christopher Hitchens, who led by example and followed reason wherever it took them. At the time, it seemed to me that a career as an academic scientist would be the most intellectually satisfying profession imaginable. It would allow me to dive deep into questions at the frontier of human knowledge, teach and train students to think critically, and pass on the virtues of boldly engaging with unreason in the search for truth to a new generation.
But it seems clear to me that academia now is not as it was advertised a decade ago when I started down this path. It is no longer a refuge for outspoken, free-thinking intellectuals. Instead, it seems one must now choose between living a zipper-lipped life as an academic scientist, or living a life as a fulfilled intellectual. Currently, one cannot do both.