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Why nature vs. nurture is ‘zombie idea’ we need to kill
Why do some people still believe that behavior is caused solely by genes or environment? A new paper offers some answers.

- Despite the fact that scientists have long known that behavior is caused by complex interactions between genes and environment, the debate still persists in the culture today.
- A new paper outlines three reasons why this debate persists, and why behavior isn't special — it abides by the same evolutionary processes as other traits.
- The authors say rejecting the false nature-nurture dichotomy can help kill this "zombie idea."
Which determines traits like sexual orientation, intelligence and behavior: genes or environment?
Many modern debates center on this question, from the #MeToo movement to transgender rights, to academic performance, to crime. But is the nature-nurture conversation even worth having? After all, it was more than three decades ago that the American biochemist Daniel Koshland wrote in an editorial published in Science, "The debate on nature and nurture in regard to behavior is basically over. Both are involved."
Now, a paper recently published in BioScience argues it's finally time to kill the "zombie" that is the nature-nurture debate. The authors—Marlene Zuk and Hamish G. Spencer of the University of Otago's Department of Zoology—note that behaviors aren't determined solely by genes or environment.
Zuk and Spencer divide their argument into three parts.
Behavior is not special in its evolution
Behavior, the authors write, evolves in the same manner as other traits. People often mistakenly think that behavior — particularly human behavior — exists apart from the principles of evolution, in a separate realm from other characteristics, such as height.
The authors note the Venus flytrap as an example.
"The motor cells that close the trap need exactly two signals within 20 seconds to activate. Then, at least three—not one, not four—flicks of a trigger hair are needed to signal the production of digestive enzymes. Only then can successful consumption of the prey commence."
Does this precise predatory process count as behavior? It's a tricky question, sure. But the authors raise it because:
"If we can't draw a hard and fast line separating behavior from other traits, then the same rules apply to both, and behavior evolves the same way that leg length or other physical characteristics do. That is an important conclusion, because it means that we can't invoke culture as a get-out-of-evolution-free card."
Behavior is not explained solely by genes or environment
That might be obvious enough. But the authors also argue that behaviors aren't even the result of an additive combination of the two. In other words, you can't look at a world-class sprinter and say that their skill comes from 68 percent genetics, 32 percent environment.
Rather, behaviors stem from the complex and fluid interaction between the two.
"The effect of an organism's genes depends on the organism's environment and does so just as much as the effect of an organism's environment depends on its genes," the authors write. "Genes and environment interact. The philosopher of science Evelyn Fox Keller calls this the entanglement of genotype and environment, which also conveys the inextricable nature of the relationship between the two."
Genes do not code for behavior
Zuk and Spencer suggest that the way people talk about genes tends to confuse the public about the role genetics play in influencing behavior. For example, you might read a study saying that scientists have "found the gene for" intelligence, criminality, or whatever trait.
"What scientists mean when they talk about a gene for a trait is that variation at that gene (e.g., differences in the DNA sequence of that gene) leads, in a certain range of environments, to variation in that trait, and the concept involved is one called heritability," the authors write.
But a gene for a trait does not act as an off-on switch that produces behavior.
"The crucial point is that, regardless of the heritability of a trait, a change in the range of environments (or, for that matter, the genetic variation affecting the trait) can change the heritability. Everything is context dependent."
Killing the zombie
So, why do we need to kill the nature-nurture zombie? Zuk and Spencer suggest that these misguided beliefs can cause us to think certain behaviors are inevitable. For example, if people with anorexia read articles saying the condition is caused solely by genetics, they might feel like there's nothing they can do to improve their health. In this way, people may feel like they have an "out" to continue these behaviors, when, in reality, environmental interventions could benefit them.
Similarly, the belief that genes determine traits like intelligence or social mobility may influence public officials not to spend as much money on certain public programs. In this way, the nature-nurture dichotomy causes people to do nothing at all.
The authors say it's time to break our conceptual link between genetics and fate.
"A rejection of that equivalence, along with a view of the nature of the entanglement of genes and the environment, would be real progress, and just might kill the zombie."
- The Pessimistic Brain: Wired to Be Negative? - Big Think ›
- Why Some Apples Fall Far From The Tree - Big Think ›
- Where Does Happiness Come From: Nature or Nurture? - Big Think ›
A Cave in France Changes What We Thought We Knew About Neanderthals
A cave in France contains man’s earliest-known structures that had to be built by Neanderthals who were believed to be incapable of such things.
In a French cave deep underground, scientists have discovered what appear to be 176,000-year-old man-made structures. That's 150,000 years earlier than any that have been discovered anywhere before. And they could only have been built by Neanderthals, people who were never before considered capable of such a thing.
This is going to force a major shift in the way we see these early hominids. Researchers had thought that Neanderthals were profoundly primitive, and just barely human. This cave in France's Aveyron Valley changes all that: It's suddenly obvious that Neanderthals were not quite so unlike us.
According to The Atlantic, Bruniquel Cave was first explored in 1990 by Bruno Kowalsczewski, who was 15 at the time. He'd spent three years digging away at rubble covering a space through which his father felt air moving.
Some members of a local caving club managed to squeeze through the narrow, 30-meter long tunnel Kowalsczewski had dug to arrive in a passageway. They followed it past pools of water and old animal bones for over 330 meters before coming into a large chamber and a scene they had no reason to expect: Stalagmites that someone had broken into hundreds of small pieces, most of which were arranged into two rings—one roughly 6 meters across, and one 2 meters wide—with the remaining pieces stacked into one of four piles or leaning against the rings. There were also indications of fires and burnt bones.
Image source: Etienne FABRE - SSAC
What the?
A professional archeologist, Francois Rouzaud, determined with carbon dating that a burnt bear bone found in the chamber was 47,600 years old, which made the stalagmite structures older than any known cave painting. It also put the cave squarely within the age of the Neanderthals since they were the only humans in France that early. No one had suspected them of being capable of constructing complex forms or doing anything that far underground.
After Rouzard suddenly died in 1999, exploration at the cave stopped until life-long caver Sophie Verheyden, vacationing in the area, heard about it and decided to try and uranium-date the stalagmites inside.
The team she assembled eventually determined that the stalagmites had been broken up by people 176,000 years ago, way farther back even than Rouzard had supposed.
There weren't any signs that Neanderthals lived in the cave, so it's a mystery what they were up to down there. Verheyden thinks it's unlikely that a solitary artist created the tableaux, and so an organized group of skilled workers must've been involved. And “When you see such a structure so far into the cave, you think of something cultural or religious, but that's not proven," Verheyden told The Atlantic.
Whatever they built, the Bruniquel Cave reveals some big surprises about Neanderthals: They had fire, they built things, and likely used tools. Add this to recent discoveries that suggest they buried their dead, made art, and maybe even had language, and these mysterious proto-humans start looking a lot more familiar. A lot more like homo sapiens, and a lot more like distant cousins lost to history.
Paul Hudson/Flickr
Psychopath-ish: How “healthy” brains can look and function like those of psychopaths
A recent study used fMRI to compare the brains of psychopathic criminals with a group of 100 well-functioning individuals, finding striking similarities.
Obscure freaky smiling psycho man
- The study used psychological inventories to assess a group of violent criminals and healthy volunteers for psychopathy, and then examined how their brains responded to watching violent movie scenes.
- The fMRI results showed that the brains of healthy subjects who scored high in psychopathic traits reacted similarly as the psychopathic criminal group. Both of these groups also showed atrophy in brain regions involved in regulating emotion.
- The study adds complexity to common conceptions of what differentiates a psychopath from a "healthy" individual.
When considering what precisely makes someone a psychopath, the lines can be blurry.
Psychological research has shown that many people in society have some degree of malevolent personality traits, such as those described by the "dark triad": narcissism (entitled self-importance), Machiavellianism (strategic exploitation and deceit), and psychopathy (callousness and cynicism). But while people who score high in these traits are more likely to end up in prison, most of them are well functioning and don't engage in extreme antisocial behaviors.
Now, a new study published in Cerebral Cortex found that the brains of psychopathic criminals are structurally and functionally similar to many well-functioning, non-criminal individuals with psychopathic traits. The results suggest that psychopathy isn't a binary classification, but rather a "constellation" of personality traits that "vary in the non-incarcerated population with normal range of social functioning."
Assessing your inner psychopath
The researchers used functional magnetic resonance imaging (fMRI) to compare the brains of violent psychopathic criminals to those of healthy volunteers. All participants were assessed for psychopathy through commonly used inventories: the Hare Psychopathy Checklist-Revised and the Levenson Self-Report Psychopathy Scale.
Experimental design and sample stimuli. The subjects viewed a compilation of 137 movie clips with variable violent and nonviolent content.Nummenmaa et al.
Both groups watched a 26-minute-long medley of movie scenes that were selected to portray a "large variability of social and emotional content." Some scenes depicted intense violence. As participants watched the medley, fMRI recorded how various regions of their brains responded to the content.
The goal was to see whether the brains of psychopathic criminals looked and reacted similarly to the brains of healthy subjects who scored high in psychopathic traits. The results showed similar reactions: When both groups viewed violent scenes, the fMRI revealed strong reactions in the orbitofrontal cortex and anterior insula, brain regions associated with regulating emotion.
These similarities manifested as a positive association: The more psychopathic traits a healthy subject displayed, the more their brains responded like the criminal group. What's more, the fMRI revealed a similar association between psychopathic traits and brain structure, with those scoring high in psychopathy showing lower gray matter density in the orbitofrontal cortex and anterior insula.
There were some key differences between the groups, however. The researchers noted that the structural abnormalities in the healthy sample were mainly associated with primary psychopathic traits, which are: inclination to lie, lack of remorse, and callousness. Meanwhile, the functional responses of the healthy subjects were associated with secondary psychopathic traits: impulsivity, short temper, and low tolerance for frustration.
Overall, the study further illuminates some of the biological drivers of psychopathy, and it adds nuance to common conceptions of the differences between psychopathy and being "healthy."
Why do some psychopaths become criminals?
The million-dollar question remains unanswered: Why do some psychopaths end up in prison, while others (or, people who score high in psychopathic traits) lead well-functioning lives? The researchers couldn't give a definitive answer, but they did note that psychopathic criminals had lower connectivity within "key nodes of the social and emotional brain networks, including amygdala, insula, thalamus, and frontal pole."
"Thus, even though there are parallels in the regional responsiveness of the brain's affective circuit in the convicted psychopaths and well-functioning subjects with psychopathic traits, it is likely that the disrupted functional connectivity of this network is specific to criminal psychopathy."
Fighting online misinformation: We're doing it wrong
Counterintuitively, directly combating misinformation online can spread it further. A different approach is needed.
- Like the coronavirus, engaging with misinformation can inadvertently cause it to spread.
- Social media has a business model based on getting users to spend increasing amounts of time on their platforms, which is why they are hesitant to remove engaging content.
- The best way to fight online misinformation is to drown it out with the truth.
A year ago, the Center for Countering Digital Hate warned of the parallel pandemics — the biological contagion of COVID-19 and the social contagion of misinformation, aiding the spread of the disease. Since the outbreak of COVID-19, anti-vaccine accounts have gained 10 million new social media followers, while we have witnessed arson attacks against 5G masts, hospital staff abused for treating COVID patients, and conspiracists addressing crowds of thousands.
Many have refused to follow guidance issued to control the spread of the virus, motivated by beliefs in falsehoods about its origins and effects. The reluctance we see in some to get the COVID vaccine is greater amongst those who rely on social media rather than traditional media for their information. In a pandemic, lies cost lives, and it has felt like a new conspiracy theory has sprung up online every day.
How we, as social media users, behave in response to misinformation can either enable or prevent it from being seen and believed by more people.
The rules are different online
Credit: Pool via Getty Images
If a colleague mentions in the office that Bill Gates planned the pandemic, or a friend at dinner tells the table that the COVID vaccine could make them infertile, the right thing to do is often to challenge their claims. We don't want anyone to be left believing these falsehoods.
But digital is different. The rules of physics online are not the same as they are in the offline world. We need new solutions for the problems we face online.
Now, imagine that in order to reply to your friend, you must first hand him a megaphone so that everyone within a five-block radius can hear what he has to say. It would do more damage than good, but this is essentially what we do when we engage with misinformation online.
Think about misinformation as being like the coronavirus — when we engage with it, we help to spread it to everyone else with whom we come into contact. If a public figure with a large following responds to a post containing misinformation, they ensure the post is seen by hundreds of thousands or even millions of people with one click. Social media algorithms also push content into more users' newsfeeds if it appears to be engaging, so lots of interactions from users with relatively small followings can still have unintended negative consequences.
The trend of people celebrating and posting photos of themselves or loved ones receiving the vaccine has been far more effective than any attempt to disprove a baseless claim about Bill Gates or 5G mobile technology.
Additionally, whereas we know our friend from the office or dinner, most of the misinformation we see online will come from strangers. They often will be from one of two groups — true believers, whose minds are made up, and professional propagandists, who profit from building large audiences online and selling them products (including false cures). Both of these groups use trolling tactics, that is, seeking to trigger people to respond in anger, thus helping them reach new audiences and thereby gaming the algorithm.
On the day the COVID vaccine was approved in the UK, anti-vaccine activists were able to provoke pro-vaccine voices into posting about thalidomide, exposing new audiences to a reason to distrust the medical establishment. Those who spread misinformation understand the rules of the game online; it's time those of us on the side of enlightenment values of truth and science did too.
How to fight online misinformation
Of course, it is much easier for social media companies to take on this issue than for us citizens. Research from the Center for Countering Digital Hate and Anti-Vax Watch last month found that 65% of anti-vaccine content on social media is linked to just twelve individuals and their organizations. Were the platforms to simply remove the accounts of these superspreaders, it would do a huge amount to reduce harmful misinformation.
The problem is that social media platforms are resistant to do so. These businesses have been built by constantly increasing the amount of time users spend on their platforms. Getting rid of the creators of engaging content that has millions of people hooked is antithetical to the business model. It will require intervention from governments to force tech companies to finally protect their users and society as a whole.
So, what can the rest of us do, while we await state regulation?
Instead of engaging, we should be outweighing the bad with the good. Every time you see a piece of harmful misinformation, share advice or information from a trusted source, like the WHO or BBC, on the same subject. The trend of people celebrating and posting photos of themselves or loved ones receiving the vaccine has been far more effective than any attempt to disprove a baseless claim about Bill Gates or 5G mobile technology. In the attention economy that governs tech platforms, drowning out is a better strategy than rebuttal.
Imran Ahmed is CEO of the Center for Countering Digital Hate.
Self-awareness is what makes us human
Because of our ability to think about thinking, "the gap between ape and man is immeasurably greater than the one between amoeba and ape."
