The question of whether it is genes or environment that largely shapes human behaviour has been debated for centuries. During the second half of the 20th century, there were two camps of scientists each believing that nature or nurture, respectively, was exclusively at play.
This view is becoming increasingly rare, as research is demonstrating that genes and environment are actually interconnected and can amplify one another. During an event at Berlin Science Week on November 7, organised by the Royal Society, we discussed how the debate is changing as a result of recent findings.
Take literacy. Making language visible is one of the most extraordinary achievements of human beings. Reading and writing is fundamental to our ability to thrive in the modern world, yet some individuals find it difficult to learn. This difficulty can arise for many reasons, including dyslexia, a neuro-developmental disorder. But it turns out neither genes nor environment are fully responsible for differences in reading ability.
Genetics and the neuroscience of reading
Reading is a cultural invention and not a skill or function that was ever subject to natural selection. Written alphabets originated around the Mediterranean about 3,000 years ago, but literacy only became widespread from the 20th century. Our use of the alphabet, however, is grounded in nature. Literacy hijacks evolved brain circuitry to link visible language to audible language by letter-sound mapping.
Brain scans show that this reading network is apparent in pretty much the same place in the brain in everybody. It forms when we learn to read and strengthens connections between our brains language and speech regions, as well as a region that has become known as the visual word form area.
The design for building the underlying circuitry is somehow encoded in our genomes. That is, the human genome encodes a set of developmental rules that, when played out, will give rise to the network.
However, there is always variation in the genome and this leads to variation in the way these circuits develop and function. This means there are individual differences in ability. Indeed, variation in reading ability is substantially heritable across the general population, and developmental dyslexia is also largely genetic in origin.
This is not to say that there are genes for reading. Instead, there are genetic variations that affect how the brain develops in ways that influence how it functions. For unknown reasons, some such variants negatively affect the circuits required for speaking and reading.
Environment matters too
But genes are not the whole story. Lets not forget that experience and active instruction are needed for the changes in brain connectivity that enable reading to occur in the first place though we dont yet know to what extent.
Research has shown that most often problems with literacy are likely underpinned by a difficulty in phonology the ability to segment and manipulate the sounds of speech. It turns out that people with dyslexia also tend to struggle with learning how to speak when infants. Experiments have shown that they are slower than other people to name objects. This also applies to written symbols and relating them to speech sounds.
And here nurture comes in again. Difficulties in learning to read and write are particularly visible in languages with complex grammar and spelling rules, such as English. But they are far less obvious in languages with more straightforward spelling systems, such as Italian. Tests of phonology and object naming, however, can detect dyslexia in Italian speakers too.
So the difference that is found in dyslexic brains is likely the same everywhere, but will nevertheless play out very differently in different writing systems.
Amplification and cycles
Nature and nurture are traditionally set in opposition to each other. But in truth, the effects of environment and experience often tend to amplify our innate predispositions. The reason is that those innate predispositions affect how we subjectively experience and respond to various events, and also how we choose our experiences and environments. For example, if you are naturally good at something you are more likely to want to practice it.
This dynamic is especially evident for reading. Children with greater reading ability are more likely to want to read. This will of course further increase their reading skills, making the experience more rewarding. For children with lower natural reading ability, the opposite tends to happen they will choose to read less, and will fall farther behind their peers over time.
These cycles also offer a window of intervention. As we have seen in the case of Italian readers, nurture can mitigate the effects of an adverse genetic predisposition. Similarly, a good teacher who knows how to make practice rewarding can help poor readers by allowing short cuts and mnemonics for spelling. In this way, dyslexic readers can become good readers and enjoy it. Reward and practice enhance each other, leading to more motivation and more practice in a positive feedback loop.
So instead of thinking of nature and nurture as adversaries in a zero sum game, we should think of them as feedback loops where a positive influence of one factor increases the positive influence of the other producing not a sum but an enhancement. Of course, the same applies to negative feedback, and so we have both virtuous and vicious circles.
Because inheritance (genetic as well as cultural) matters, this effect is also visible on a larger scale spanning several generations. In the past, parents who sent their children to school created an advantageous environment for them and their grandchildren. But in turn, the parents benefited from the existence of a culture that invested in schools. Of course, such investments are not always spread evenly and may flow more towards those already in an advantageous position. Such a circle is sometimes referred to as the Matthew effect good things come to those who already have them.
The interactive loops between nature and nurture extend beyond the lives of individuals, playing out across communities and over generations. Recognising these dynamics gives us some power to break these feedback loops, both in our own lives and more widely in society and culture.
This article by Kevin Mitchell and Uta Frith first appeared in 2019 in The Conversation via Creative Commons License.
Image: Donar Reiskoffer/Wikimedia Commons/Creative Commons 3.0.
Originally posted here:
- Scientist Who Discovered BRCA1 Gene to Give Free Talk on Cancer And Genetics - Noozhawk - January 19th, 2020
- Genetic testing firm 23andMe is first to create a drug using its customers' DNA - The Times - January 19th, 2020
- Hackensack Meridian Health Center for Discovery and Innovation to Host Genomic Medicine Symposium - P&T Community - January 19th, 2020
- 11 Year-Old Bertrand Might Cant Cry Scientists Have Now Discovered Why - SciTechDaily - January 19th, 2020
- Transposons Identified as Likely Cause of Undiagnosed Diseases - The Scientist - January 19th, 2020
- Do genetic ancestry tests know if you're Palestinian? A cautionary tale of race and science - ABC News - January 19th, 2020
- Controlling Our Own Evolution: What is the Future of Gene-Editing? - The Globe Post - January 19th, 2020
- There is a new player in adult bone healing - Baylor College of Medicine News - January 19th, 2020
- Air Pollution, Evolution, and the Fate of Billions of Humans - The New York Times - January 19th, 2020
- A New York Times column on 'Jewish genius' draws criticism for linking to a debunked University of Utah study - Salt Lake Tribune - January 5th, 2020
- Ambroxol Reverses Bone Damage in Girl With GD Type 1, Case Study Shows - Gaucher Disease News - January 5th, 2020
- Gene editing breakthroughs that cured genetic diseases in 2019 - The Star Online - January 5th, 2020
- Digid8 and the Emergence of DNA Matchmaking - Study Breaks - January 5th, 2020
- Etched in DNA: Decoding the secrets of the past - Christian Science Monitor - January 5th, 2020
- The Face of Science - Clemson World magazine - January 5th, 2020
- Aborting Babies Because They're Gay: Coming Soon to China - Patheos - January 5th, 2020
- Mutants among us: "Natural short sleepers" reveal the genetics of sleep - Inverse - January 5th, 2020
- The End of Infertility Is in Sight - UCSF News Services - January 5th, 2020
- Who is a Jew? DNA home testing adds new wrinkle to age-old debate - The Jewish News of Northern California - December 1st, 2019
- Humans and autoimmune diseases continue to evolve together - Medical News Today - December 1st, 2019
- Mutations in emerging autism gene tied to distinct traits - Spectrum - December 1st, 2019
- Gail Fisher's 'Dog Tracks': Spoiling you dog with extra food could cut short its life - The Union Leader - December 1st, 2019
- In a Wisconsin village, the doctor makes house calls and sees the rarest diseases on Earth - USA TODAY - December 1st, 2019
- Alzheimer's and Autism: Researchers Pinpoint Genetic Mutations Overlapping in Both Diseases - Being Patient - December 1st, 2019
- How do consumer DNA tests from the US and China stack up? - Abacus - December 1st, 2019
- Collection of genetic data leads to privacy concerns - The New Economy - December 1st, 2019
- Is sexual orientation genetic? Yes and no, an extensive study finds - Haaretz - November 19th, 2019
- Sexual orientation cannot be changed at will, lawyers argue - The Straits Times - November 19th, 2019
- Adam and Eve Are Possible: A Second Bite at the Genetic Apple - Christianheadlines.com - November 19th, 2019
- InterVenn Biosciences Announces Positive Interim Clinical Trial Results and Appoints Biotech Veteran Klaus Lindpaintner, M.D. as Chief Scientific and... - November 19th, 2019
- How maternal Zika infection results in newborn microcephaly - Baylor College of Medicine News - November 19th, 2019
- Dicerna scores broad, 'rest of liver' deal with Novo Nordisk, bagging $225M in cash to hit some 30 targets with RNAi platform - Endpoints News - November 19th, 2019
- Sexual orientation cannot be wilfully changed, say lawyers fighting to repeal Section 377A - The Straits Times - November 19th, 2019
- The American Heart Association's Annual Conference Comes to Philly This Weekend - Philadelphia magazine - November 19th, 2019
- Clear link between genetics and depressive symptoms uncovered - The Age - November 19th, 2019
- At-Home DNA Tests Still Need the 'Human Touch,' Say Panelists at Genomics Roundtable Workshop - National Academies of Sciences, Engineering, and... - November 19th, 2019
- How in utero Zika virus infection can lead to microcephaly in newborns: Baylor research - Outbreak News Today - November 19th, 2019
- Taller People have Increased Risk of Irregular Heartbeat - News18 - November 19th, 2019
- In Down syndrome mouse model, scientists reverse intellectual deficits with drugs - University of California - November 19th, 2019
- Alector Reports Recent Business Highlights and Third Quarter 2019 Financial Results - GlobeNewswire - November 19th, 2019
- One of the World's Greatest Geneticists, He Gave Up British Citizenship for India - The Better India - November 19th, 2019
- Section 377A constitutional challenge: Expert evidence reveal sexual orientation cannot be changed at will, lawyers argue - The Online Citizen - November 19th, 2019
- Co-creator of CRISPR lectures about future applications of genome editing technology - Daily Bruin - November 19th, 2019
- Connecting gene mutations, rare genetic diseases - Baylor College of Medicine News - October 28th, 2019
- Utah researchers discover link between certain brain cells and anxiety, OCD - KSL.com - October 28th, 2019
- UH Receives $2M to Study Cancer Risks of Environmental Toxins - Big Island Now - October 28th, 2019
- Genetic testing could keep you healthy. But what about personal info? - Deseret News - October 28th, 2019
- Student group works to foster diversity in the sciences - UChicago News - October 28th, 2019
- Takeaways from ASHG 2019 in Houston: Users of Bionano's Saphyr System Presented Validation Results for FSHD, Repeat Expansion Disorders and Digital... - October 28th, 2019
- DNA research holds the keys to human history but it's being weaponized by politicians - Haaretz - October 28th, 2019
- Scientists have created the first-ever 18-carbon ring, a major feat of molecular architecture - Massive Science - October 28th, 2019
- Law, Privacy and Genome Human Rights Failure in Russia - Putin's Fascination with Hitler's Eugenics Project - Communal News - October 28th, 2019
- Neural activity plays an important role in longevity - CMU The Tartan Online - October 28th, 2019
- Book Summary: Genetics and the Aryan Debate by Shrikant Talageri- I - IndiaFacts - October 28th, 2019
- Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More - May 25th, 2019
- Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More - May 25th, 2019
- Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto - May 25th, 2019
- Cryptocurrency News: Looking Past the Bithumb Crypto Hack - May 25th, 2019
- Cryptocurrency News: XRP Validators, Malta, and Practical Tokens - May 25th, 2019
- Cryptocurrency News: Bitcoin ETF Rejection, AMD Microchip Sales, and Hedge Funds - May 25th, 2019
- Cryptocurrency News: What You Need to Know This Week - May 25th, 2019
- Bitcoin Rise: Is the Recent Bitcoin Price Surge a Sign of Things to Come or Another Misdirection? - May 25th, 2019
- Cryptocurrency News: Vitalik Buterin Doesn’t Care About Bitcoin ETFs - May 25th, 2019
- Cryptocurrency News: New Exchanges Could Boost Crypto Liquidity - May 25th, 2019
- Human genetics - Wikipedia - May 5th, 2019
- Human Genetics - medschool.ucla.edu - May 5th, 2019
- Department of Human Genetics | The University of Chicago - May 5th, 2019
- Human genetics | biology | Britannica.com - May 2nd, 2019
- What is Bitcoin Cash? - finance.yahoo.com - April 29th, 2019
- Bitcoin Soars As Ethereum, Ripple's XRP, Bitcoin Cash, And ... - April 29th, 2019
- Bitcoin Cash - finance.yahoo.com - April 29th, 2019
- What is Bitcoin Cash? - Coin Rivet - April 29th, 2019
- Bitcoin Cash - Wikipedia - April 29th, 2019
- Ripple Price Forecast: XRP vs SWIFT, SEC Updates, and More - April 21st, 2019
- Cryptocurrency News: Looking Past the Bithumb Crypto Hack - April 21st, 2019
- Cryptocurrency News: This Week on Bitfinex, Tether, Coinbase, & More - April 21st, 2019
- Cryptocurrency News: XRP Validators, Malta, and Practical Tokens - April 21st, 2019
- Cryptocurrency News: Bitcoin ETFs, Andreessen Horowitz, and Contradictions in Crypto - April 21st, 2019
- Cryptocurrency News: New Exchanges Could Boost Crypto Liquidity - April 21st, 2019
- Cryptocurrency News: Bitcoin ETF Rejection, AMD Microchip Sales, and Hedge Funds - April 21st, 2019