Liberty and Fertility: Is Human Population Decline Inevitable?
A proposition stemming from affective science and evolutionary theory suggests that depopulation is unavoidable.
In a comprehensive study published in The Lancet, an international team of demographers predicts a global population peak in 40 years, followed by a continuous decline. This decline, driven primarily by low birth rates, is expected to continue unabated, with far-reaching implications for society, the economy, and geopolitics.
Although The Lancet forecast only extends to the year 2100, there is a tangible prospect that low birth rates could persist well beyond this century, potentially leading humanity down a gradual path toward zero population. As unsettling as this prospect may be, the plausibility of such a scenario merits investigation.
Our first clue comes from demographic data, which consistently shows that as socioeconomic conditions improve, birth rates tend to decline. This pattern is observed both within countries when comparing different income levels and globally between nations, spanning ethnicities, cultures, and creeds.
To understand this phenomenon, which is in stark contrast to other species, we need to take a closer look at human motivation and examine the role of emotions in particular.
Emotions and choice
In different fields, from neuroscience to economics, there is a growing interest in understanding how emotions influence judgment and choices. Extensive research attests to the central role emotions play in shaping the most consequential decisions in our lives. Their influence on decision-making is compelling and pervasive, altering both the focus and the depth of our thoughts. Anger, for instance, tends to truncate our thinking, leading to snap decisions that may not always be the most judicious. Meanwhile, positive feelings wield a more subtle yet equally formidable power to influence human thought and behavior.
For eons, natural selection has meticulously molded the human body, including the intricate workings of the brain. In the context of evolution, reproduction is what ultimately counts, and as a result, the most potent emotional rewards steer human behavior toward achieving this end. From the ecstasy of sexual encounters to the tender joys of romance, as well as the devotion to offspring, evolution has instilled within us a complex array of emotional incentives to ensure the survival and proliferation of our species.
Despite biological links between procreation and emotional rewards, humans have devised ingenious methods to separate them. A prime illustration of this can be seen in the invention of contraceptives, which has allowed couples to enjoy sex while simultaneously avoiding conception.
Alternatively, consider the deep bond between a devoted pet owner and their furry companion. Pets have the remarkable ability to elicit feelings of affection that are akin to the love a parent feels for their child. This affection is a primary motivation for people to keep pets. To that end, some pet breeds have been deliberately bred to be cute and cuddly, tapping into our parental instincts. It's no wonder that pet ownership is expanding, with more and more people embracing their pets as surrogate offspring.
Another example of our capacity to uncouple procreation from its emotional rewards is found in the rise of virtual romantic relationships. With the advent of AI chatbots that mimic human speech, there are reports of people forming deep emotional connections with their virtual companions and even falling in love with them. The emergence of such novel forms of emotional bonding raises interesting questions about the future of human relationships and how they will continue to evolve over time.
To explore how far emerging technologies could transform our lifestyles and relationships, here’s a thought experiment: Imagine a revolutionary new invention called Emode (Emotion Modification Device) that gives the user unparalleled control over their emotions. With an Emode, you can: (1) experience the entire spectrum of human emotions; and (2) choose how you feel at any moment, irrespective of the circumstances you are in.
If you were given an Emode, a world of possibilities would open for you. What would you do? Would you use it to better empathize with others and feel what they are feeling, or to make yourself feel better? And how might the Emode impact your personal and professional relationships, career, and leisure activities? Do you wish to be in charge of your own emotions, or do you prefer that chance and circumstance dictate them? If you were granted the freedom to choose how you feel, would you ever willingly relinquish that choice? These are some of the thought-provoking questions that merit our consideration.
The Emode thought experiment sheds light on the nature of human choice and the degree to which we can predict it. For instance, if Emodes were to become commercially available, it seems inevitable that they would become ubiquitous. Furthermore, we can infer that the closer a real-life invention is to the hypothetical Emode, the greater the chances of it becoming popular and commercially successful. This is because, firstly, people seek happiness over unhappiness, and secondly, they aim to achieve their goals with minimal effort.
In other words, most people would opt for effortless and cost-free enjoyment over the kind that requires hard work and enduring stressful, difficult, or unpleasant experiences. Additionally, unconditional happiness that Emode exemplifies is not to be confused with the types of enjoyment that have hidden or deferred costs, such as hangovers or drug withdrawals, which are clearly inferior.
In summary, there are three key points to consider: (1) Our brain’s reward system has been honed by natural selection to encourage reproductive behaviors; (2) Human ingenuity knows no bounds when it comes to finding new and potent ways to activate this reward system; (3) Ultimately, we all seek a sense of enduring fulfillment that is immune to any condition that could undermine it.
Our hypothetical Emode’s relevance to the real world can be best understood through a related concept. We define an emode (uncapitalized) as any tool, method, or mechanism that a person uses to alter their emotional state. In contrast to the Emode ideal, a typical emode operates within a limited spectrum of emotional states and possesses a limited degree of effectiveness in eliciting said states.
Take, for instance, the ubiquitous TV, a classic emode that enables us to alleviate boredom or unwind after a long day. The television’s enduring popularity can be largely attributed to its ability to excite curiosity. By catering to this and other emotions, the TV has become a staple device for those seeking entertainment. Modern streaming services like Netflix, YouTube, and TikTok have taken this to the next level, providing an even wider range of content with unparalleled convenience. Consequently, our screen time has increased as the emotional stimuli from these platforms often prove more compelling than our surroundings.
The vibrator (a sex toy) has earned its reputation as a popular emode. Designed for self-pleasure, it taps into the potent emotional incentives that evolution has honed to promote reproduction. Despite its simple mechanics, the vibrator remains a reliable and effective emode.
Mood-altering substances, many of which remain illicit, represent another facet of emode technology. As many can attest from personal experience, even small doses of certain chemicals can yield powerful emotional effects. However, the sought-after mood improvements are typically short-lived, often resulting in unpleasant aftereffects. The drugs available today have many drawbacks, yet they also offer glimpses into the potential positives that can be achieved through the manipulation of our biology. If it weren't for those promising possibilities, there wouldn't be an endless cultural fascination with such substances.
Neurons, those marvelous cells that allow us to feel, think, and experience the world, are essentially tiny chemical factories. Current mood-enhancing drugs are rather primitive in their attempts to alter the internal chemistry of these cells from the outside. What if we could reprogram the neurons themselves to achieve a permanent mood improvement while minimizing unwanted side effects? As society moves away from debating the ethics of such a practice, the focus will shift to determining the safest and most responsible means of doing so.
Emodes don’t always need an external form. Mindfulness meditation, for instance, is a well-established technique that can alleviate stress, anxiety, anger, and other unwelcome emotions. Despite its ancient origins and proven benefits, however, mindfulness meditation is not a widely embraced emode. It demands significant time and dedication, rendering it impractical for many. Moreover, it appears to be more adept at reducing negative emotions than fostering positive ones.
Hope is an essential reward mechanism that evolution has equipped us with, crucial to our species' historical ascent. Without it, it's hard to imagine how we could have accomplished so much. Here's how it works: When we anticipate future happiness, we experience a surge of positive emotions in the present. This surge of optimism and excitement motivates us to strive towards our desired future.
Religious practices, psychotherapy, and entertainment have often employed hope's emotive qualities. The methods for invoking hope are diverse and encompass various techniques, ranging from prayer to gambling. Throughout history, significant social, cultural, and intellectual capital has been invested in developing and promoting these emodes of hope, often to the detriment of competing approaches.
The market for emodes is vast and diverse, encompassing everything from cocktails and pop songs to ASMR streams and computer games, from lottery tickets to meditation and prayer. Our emotions and our intellect, the two pillars of our humanity, ensure that emode technology is constantly evolving, with new types of emodes emerging and existing ones improving. As with any consumer technology, economic factors will continue to make emodes more accessible and affordable. While it remains to be seen whether a definitive Emode will emerge, one thing seems certain: we can expect an abundance of increasingly potent emodes in the years ahead.
Fertility and choice
In developed countries, people have an ever-increasing number of entertainment, lifestyle, and career options to choose from, all of which compete with the time and effort required to raise children. Novel emodes such as gaming, social media, adult websites, streaming services, and AI chatbots also shape our choices about parenthood. While no single emode has a decisive effect on birth rates, a combination of many different emodes can support a lifestyle that is emotionally satisfying without the need for children.
As people continue to find fulfillment in non-reproductive pursuits, the choice to have children becomes less emotionally compelling. Is it possible that this dynamic could ultimately drive our species to extinction, an unintended consequence of our pursuit of happiness?
A fertility rate of at least 2.1 births per woman is needed to prevent population decline. This figure accounts for two children to replace the parents, and an additional 0.1 to compensate for early mortality and the higher likelihood of male births. Any rate below 2.1 is known as sub-replacement fertility.
Over the past six decades, fertility rates have been decreasing worldwide, albeit with regional variations. Europe and the Americas have already fallen below the replacement level, while Asia is on the cusp. Only Africa remains well above the 2.1 threshold. However, as African economies and living standards continue to improve, they are expected to follow the path of developed nations. The Lancet study predicts that by 2050, 151 countries will experience sub-replacement fertility, and this number is projected to increase to 183 by 2100. Does this suggest an inevitable fate, or might there be some ways to escape this trajectory?
“Nature will save us”
Even countries grappling with low fertility rates have outliers—prolific families with many children. The tantalizing thought follows: might natural selection eventually favor these "high-fertility" families, catalyzing a population resurgence? This argument has an appealing simplicity. After all, studies do show that parents with more children tend to have offspring who follow suit. Yet, what proponents often overlook is that this correlation is statistically weak. Mathematical analyses confirms that these familial patterns, however intriguing, lack the potency to stave off population decline.
“Government will save us”
Governments have been exploring financial and other incentives as a means of bolstering birth rates, but success in this area has proven elusive. South Korea, for instance, has spent a staggering $210 billion over the past 16 years encouraging women to have more babies, yet its fertility rate has fallen to 0.81, making it the lowest in the world for the third consecutive year.
Despite the efforts, no country has managed to successfully incentivize parenthood over the long term. Two obstacles stand in the way. First, there is the question of who will be taxed to pay for the incentives. Second, incentives alone cannot address the root cause of the inverse relationship between prosperity and fertility rates, which we attribute to the growth of emode technology.
Unable to incentivize fertility and halt labor force shrinkage, governments are likely to shift their focus toward AI automation to maintain living standards and sustain economic development, with Japan pioneering this approach. An alternative approach is to bolster the labor force through increased immigration, but this option remains politically unpopular.
“Religion (ideology) will save us”
Could global population decline eventually be halted by groups with high fertility rates, such as the ultra-religious, or by countries like Israel, which is experiencing a long-term baby boom? While Israel's fertility rate of 2.9 is the highest of any developed country, it is an outlier due to ongoing conflicts which have fostered a war mentality among parents, reminiscent of the post-WW2 population surge in many countries. However, no conflict lasts forever, and Israel's baby boom will likely subside at some point. As for the ultra-religious, while they tend to have higher fertility rates, they also face high attrition rates in secular societies. Moreover, as societies become more developed, they tend to become less religious. This trend is unlikely to reverse, and ultra-religious groups will likely dwindle as younger members seek the freedoms of a more secular culture.
“Science will save us”
Could science and technology hold the key to averting the fertility crisis? One avenue that holds promise is extending reproductive years. With a greater window of opportunity, people may be more inclined to have children. Fertility treatments such as IVF and ICSI are already available, while full-term incubators or artificial wombs may become a reality in the near future. Medical advances may also extend human lifespan, further increasing reproductive years.
However, fertility rates have plummeted while life expectancy at birth has more than doubled over the past century and a half, and life expectancy at age 15 has increased by about 25 years. Additionally, even in Scandinavian countries, where fertility treatments are free for the first child, they only account for 1 in 20 births. This suggests that longevity and reproductive technology have a minor influence on fertility trends. In contrast, motivation and thus emode technology play a decisive role.
The Emode hypothesis
The Emode hypothesis, as proposed here, posits that sub-replacement fertility is an unintended consequence of our increasing reliance on technology to manage our emotions. The rapid spread of such technology is seemingly unstoppable, defying containment by any social policy short of draconian measures. Now that the genie of emode technology is unleashed, the very pursuit of happiness that drives us may be hastening the demise of our species. Furthermore, the implications could extend beyond humanity, offering a plausible explanation for the conspicuous absence of intelligent life beyond our own planet.
In order to expand the Emode hypothesis and address the Fermi paradox, an additional, well-founded assumption is required. Specifically, we presume that evolution by natural selection is only capable of producing sentient intelligence. This assumption stipulates that sentience, characterized by the capacity to experience positive and negative emotions, is a necessary aspect of any intelligence that possesses agency and can innovate technology. (The implication for AI is that without sentience, AI lacks the capacity for agency, though it can still be a highly advanced tool, as is currently the case.)
With these assumptions in place, we can trace the evolutionary arc of intelligent life: (1) a long period of evolution by natural selection, a process fueled by random mutations, repeated over countless reproductive cycles until a sentient species emerges with sufficient intelligence to develop technology; (2) a brief technological phase, during which the species advances its technology in pursuit of improved quality of life, diminishing its reproductive drive in the process; and (3) eventual extinction, typically through a gradual decline in population—a blissful fade-out.
When we contemplate the ephemeral nature of intelligent species and the rarity of planets with the capacity to sustain them, the probability of two alien civilizations blossoming in close proximity and flourishing concurrently appears quite low. Consequently, the vast distances of space, or even short spans of time, could be keeping us separated from extraterrestrial civilizations, rendering our efforts to detect them fruitless.
It is intriguing to think of intelligent life, unlike plants and microbes, as both a pinnacle of evolution and a dead end.
Author's note: This essay, originally titled "The Happiness Hypothesis" and posted here on Jun 16, 2022, has undergone significant revisions to improve its clarity. Last edited on: Sep 23, 2023. A short version titled “How the pursuit of pleasure could doom all intelligent life to a blissful extinction” was published on Big Think on Jul 14, 2023.