TIME Developmental Disorders

Researchers Zero in on the Best Way to Diagnose Autism

TIME.com stock health autism puzzle pieces
Illustration by Sydney Rae Hass for TIME

What’s the most reliable way to know if your child has autism? Is it a genetic test? Or are more traditional behavioral assessments, which measure talking and social skills, more accurate? The latest research provides some answers

Autism is a complex developmental disorder, and diagnosing it properly usually involves a combination of different tests. In the latest issue of JAMA, scientists provide the most up-to-date assessment yet of which tests work best for detecting genetic mutations associated with certain kinds of autism. Categorizing the various forms of autism will be important to guide parents to the proper care, the researchers say.

Traditionally, autism is diagnosed with behavioral tests that assess whether kids are meeting developmental milestones, such as talking, interacting with their parents and siblings, and learning to give and take in social situations. In recent years, researchers have been working on other ways to detect and potentially diagnose autism. Scientists have identified more than 100 genes connected with a higher risk of developing autism.

MORE: Study Finds Possible Association Between Autism and Air Pollution

Stephen Scherer, director of the center for applied genomics and a professor at the Hospital for Sick Children in Toronto, and his colleagues conducted a comparison test to see how the genetic tests matched up, both against each other and against the more conventional behavioral evaluations.

They studied 258 children who were diagnosed with autism spectrum disorder; all had a form of genetic testing done that looks specifically at abnormalities in the chromosomes; some had more extensive genetic testing, called whole-exome sequencing.

MORE: How Brain Scans Can Diagnose Autism With 97% Accuracy

The two genetic tests were roughly equally capable—around 8-9%—of detecting autism. Regardless of the fact they perform similarly, however, more labs and clinicians are favoring whole-exome sequencing, says Scherer. That’s concerning because the two genetic tests pick up markers for different kinds of autism, and excluding the other test in favor of the more high-tech whole-exome sequencing would miss about half of the possible genetic predictors of autism. Together the two gene-based tests can diagnose nearly 16% of cases.

“We need to use both technologies now,” he says. “If we only used one, we would miss some important information.”

The tests aren’t cheap. The chromosome-based test costs about $500, and exome sequencing slightly more. Ideally, this research suggests, both tests would be done for any child referred to a developmental pediatricians who suspects autism. But the reality is that for now, insurers may not cover both.

Scherer’s group looked at how non-genetic evaluations matched up with the genetic testing. Using factors such as brain scans to look for physical differences that might indicate autism, they divided the children into three groups based on whether they possessed physical anomalies or not. Among children with more physical abnormalities, the two types of genetic testing together diagnosed autism in 37.5% of cases.

MORE: Autism Rises: More Children than Ever Have Autism, but Is the Increase Real?

That suggests that the most accurate diagnosis of autism may come from combining all three types of tests. Not only that, says Scherer, but such testing can also categorize the type of autism that a child may have. “We need to start looking at each autism case individually, and come up with the best recommendations,” he says.

For now, based on the results of the study, he recommends that behavioral testing be the first step. Then, the chromosomal test should be done to see if it yields any additional information about a connection to autism. Even if it does not, that doesn’t mean that there aren’t genetic factors in play. If the chromosomal test is negative, Scherer argues that in some cases the whole exome sequencing might be useful.

Working with genetic counselors can help parents decide if and when this type of genetic testing is needed. “The message is that we need to use all technologies to get as much detailed information as we can to marry them all together,” he says.

TIME Research

Marijuana Does Not Affect Brain Volume, Study Finds

TIME.com stock health brain
Illustration by Sydney Rae Hass for TIME

The latest research adds to the debate over marijuana's effects on the brain

Using marijuana does not cause changes in brain volume, a new study suggests.

Public health experts have cited concerns that using marijuana could be associated with structural changes in the brain. However, a new trial comparing the brains of marijuana users and non-users to their siblings reveals that marijuana use likely does not cause changes in brain volume.

In the study, published in the journal JAMA Psychiatry, researchers looked at a large group of siblings ages 22 to 35. Of the 483 people, 262 reported ever using marijuana, even just once. The researchers then split the men and women into groups: sibling pairs who had never used marijuana, sibling pairs where both had reported using marijuana, and sibling pairs where one had used marijuana and one had not. Overall, they noticed that people who reported using marijuana had smaller volumes in certain parts of the brain—like the left amygdala, which is involved in emotional processing. However, these differences still fell within a range of volume that is considered normal.

The researchers hypothesized that in the sibling pairs where one had used marijuana and one had not, they would see differences in brain volume. But instead, they found that the exposed and unexposed siblings had the same amygdala volume. “We found no evidence for the causal influence of cannabis exposure on amygdala volume,” the authors concluded.

The researchers suggest that differences in volume could be due to other factors, like genetics or living environment. “Our study suggests that cannabis use, or at least the simple index of it that we used, does not directly impact changes in brain volumes,” says study author Arpana Agrawal, an associate professor at Washington University School of Medicine. “Instead, any relationship that we did see between cannabis use and brain volumes was due to predisposing factors that influence both cannabis use and brain volumes.”

The study did not find that brain volume has any effect on whether or not a person uses marijuana.

Another study, also published by different authors in the same journal, found that using marijuana could alter the brains of males at high risk for schizophrenia in potentially meaningful ways.

More research needs to be done to understand whether marijuana does or does not have potentially harmful effects on the brain, or whether the risks are different from one person to the next.

TIME Exercise

Working Out Doesn’t Keep Your Brain Young: Study

500048473
Klaus Tiedge—Getty Images/Blend Images

Being physically active has a lot of health benefits, but the latest research questions whether it can help the brain

Exercise can help the heart, lower the risk of diabetes, keep blood pressure in check and help you maintain a healthy weight. But researchers say you shouldn’t expect it to keep your brain alert.

In a study published in JAMA, Dr. Kaycee Sink, director of the memory assessment clinic at Wake Forest Baptist Medical Center and her colleagues come to the somewhat surprising conclusion that exercise doesn’t help elderly to maintain their brain function. Previous studies that found people who were more active documented less decline in mental abilities over time. And the theory behind the relationship made sense — physical activity can improve circulation and keep brain neurons nourished and fed with the nutrients they need to keep working properly.

MORE: How Exercise Helps Curb Alzheimer’s Symptoms

But when Sink and her team put the idea to the test with a group of 1,635 elderly, sedentary people aged 70 to 89 years, they found that exercise didn’t provide the benefits they expected for most people. The participants were randomly assigned to either a moderately vigorous exercise regimen of walking or a health education program that was interactive but didn’t involve as much physical activity. After two years, the scores on a battery of cognitive function tests for the two groups were about the same. The relationship held even after the researchers adjusted for the potential effects of other factors that could contribute to cognitive abilities.

The idea that exercise doesn’t help the brain “flies in the face of conventional wisdom,” says Sink. “But it’s possible that exercise isn’t beneficial in this group above and beyond any health education.”

MORE: Here’s the Amount of Exercise That Lowers Breast Cancer Risk

She did find that among specific subgroups, the physical activity did show some improvement in brain function. Those aged 80 years or more, for example, as well as the frailest participants, seemed to show benefits in executive functions such as recall, memory and learning. That suggests that timing and duration of physical activity may be critical.

She cautions, however, that people shouldn’t turn back to the couch. It’s also possible that what the results show isn’t so much exercise’s lack of benefit, but the health education program’s impressive effect. The education program involved interactive activities to teach the seniors about healthy behaviors, and was not simply a series of lectures that the participants absorbed passively. The study participants met regularly and made friends with their fellow classmates, and looked forward to the sessions as social outings. That social stimulation may be as important as physical activity in keeping brain functions sharp, says Sink.

Because the volunteers in the study were older, Sink says that the exercise may not have started early enough or lasted long enough for it to have significant effects on the brain. “We certainly can’t rule out that exercise is something that needs to start earlier,” she says. “Life long healthy habits are probably important.”

MORE: This Is Your Brain on Exercise

And, she says, there are other health benefits of exercise beyond the brain. “Even though we couldn’t prove that exercising is better for the brain than attending education classes, exercise is still good for the body in m any ways,” she says. “So I would say to continue to exercise and stay physically active, but also try to stay cognitively and socially active as well.”

TIME Diet/Nutrition

Omega-3 Supplements Don’t Improve Memory: Study

123549010
Getty Images

Popping fish oil pills may not be a boon to the brain, according to the latest study

The data has been building, slowly but surely, and now the strongest study yet may finally dispel the myth that taking omega-3 supplements can protect the brain from cognitive decline and dementia.

The connection between omega-3s, the fatty acids found most abundantly in foods like fish, and brain function emerged from large studies of people who answered questions about their diet and then performed tests on things like recall, memory and executive thinking functions. That data strongly suggested that people eating more omega-3s, including those who took supplements, tended to score higher on cognitive tests.

MORE: Omega 3s Reality Check: Are We Over-Exaggerating Their Benefits?

But in the latest study, published in JAMA, researchers found no such benefit when they explored the supplement in a group of 3,073 elderly people at risk of developing macular degeneration, a condition that causes vision loss with age. What set this study apart was the fact that the scientists did not rely on the participants’ recall of what they ate, but randomly assigned them to take omega-3 pills or a placebo for five years. All of the participants were tested on cognitive skills at the start of the study and came back every two years for additional assessments.

During that time, study leader Dr. Emily Chew, deputy director of the division of epidemiology and clinical applications at the National Eye Institute (part of the National Institutes of Health) says, she did not see significant differences in the cognitive scores between the two groups.

It’s possible that in Chew’s study, it was too little, too late in terms of seeing any effects of the omega-3s on cognition in this group of elderly participants. Something like omega-3 fatty acids may take years or decades to exert an effect, just as the decline associated with dementia takes place over a long time course. “The bottom line is that supplements are not the fast cure,” says Chew. “You are what you eat, and you’ve got to eat well. Maybe it was too late for some of the people in our study.”

MORE: Omega-3 Supplements Don’t Lower Heart Disease Risk After All

There are other important things to consider about Chew’s study, however, beginning with the fact that all of the participants were at high risk of developing macular degeneration. (The study was originally designed to test whether omega-3 supplements and other antioxidants could slow or reverse the vision loss in these patients.) Do people with macular degeneration differ in some ways from the average population? Does their condition make them less likely to respond to omega-3 fatty acids? The answers to those questions aren’t clear yet. Previous studies that have followed healthy participants over six years or also found that people with higher omega-3 intake did not score significantly higher on cognitive tests than those with lower levels.

Does that mean omega-3s aren’t the health-boon they were thought to be? Not necessarily. First, there’s the question of whether omega-3 fatty acids from the diet, from foods such as fatty fish, can have more potent effects on health than supplements. “It looks like high dose omega-3 supplementation is not the same as eating high amounts of omega-3s in a healthy dietary pattern high in marine fish and other beneficial foods and nutrients,” says Frank Hu, professor of nutrition and epidemiology at Harvard T.H. Chan School of Public Health, who was not involved in the study.

The takeaway for now, says Chew, is that it’s more important to adopt a long-term approach to healthy aging as opposed to a quick fix in a bottle of pills. Taking time and effort to live a healthy life, with a nutritious diet and regular exercise, may be far more potent when it comes to maintaining mental abilities than any supplement could accomplish. “Supplements cannot replace a healthy dietary pattern,” says Hu. “If you eat a healthy diet with high amounts of fruits, vegetables and marine fish, you probably don’t need to take fish oil supplements. The overall dietary pattern is more important than a single nutrient.”

TIME Innovation

How America Is Falling Behind on Scientific Research

The Aspen Institute is an educational and policy studies organization based in Washington, D.C.

These are today's best ideas

This week we’re presenting some of the most interesting ideas from the past year.

1. How did America fall so far behind on basic scientific research? (From April 29, 2015)

By Michael Hiltzik in the Los Angeles Times

2. The next leader of the U.N. should be a woman. (From March 30, 2015)

By Gillian Sorensen and Jean Krasno in the Washington Post

3. Cuba has a treatment for lung cancer, and now we can get our hands on it. (From May 12, 2015)

By Neel V. Patel in Wired

4. Technology’s greatest gift to social justice is the mobile phone camera. (From April 29, 2015)

By Robinson Meyer in the Atlantic

5. Want to change how you see the world? Rewire your brain by learning a second language. (From March 23, 2015)

By Nicholas Weiler in Science Magazine

The Aspen Institute is an educational and policy studies organization based in Washington, D.C.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME Mental Health/Psychology

This Graphic Shows What Stress Does to Your Body

Americans need to relax.

Over 40% of people in the U.S. say they are not doing enough to manage their stress, and the consequences of that could lead to all sorts of health-related problems. A recent study published in the journal Neuron showed people who are stressed have more difficulty with self-control and are more likely to choose to eat unhealthy food. If you’re like many Americans, you often be stressed about work and money, but there are good reasons to take time out of your day to relax. Here’s some examples of how stress affects your entire body.

Heather Jones

Read next: How To Calm Your Monkey Mind and Get Things Done

Download TIME’s mobile app for iOS to have your world explained wherever you go

TIME psychology

How Not To Assess Risk

Roman poet and philosopher Titus Lucretius Carus (circa 95 - 55 BC).
Spencer Arnold—Getty Images Roman poet and philosopher Titus Lucretius Carus (circa 95 - 55 BC).

Shane Parrish writes Farnam Street

It’s always good to re-read books and to dip back into them periodically. When reading a new book, I often miss out on crucial information (especially books that are hard to categorize with one descriptive sentence). When you come back to a book after reading hundreds of others you can’t help but make new connections with the old book and see it anew.

It has been a while since I read Anti-fragile. In the past I’ve talked about an Antifragile Way of Life, Learning to Love Volatility, the Definition of Antifragility , Antifragile life of economy, and the Noise and the Signal.

But upon re-reading Antifragile I came across the Lucretius Problem and I thought I’d share an excerpt. (Titus Lucretius Carus was a Roman poet and philosopher, best-known for his poem On the Nature of Things). Taleb writes:

Indeed, our bodies discover probabilities in a very sophisticated manner and assess risks much better than our intellects do. To take one example, risk management professionals look in the past for information on the so-called ​worst-case scenario ​and use it to estimate future risks – this method is called “stress testing.” They take the worst historical recession, the worst war, the worst historical move in interest rates, or the worst point in unemployment as an exact estimate for the worst future outcome​. But they never notice the following inconsistency: this so-called worst-case event, when it happened, exceeded the worst [known] case at the time.

I have called this mental defect the Lucretius problem, after the Latin poetic philosopher who wrote that the fool believes that the tallest mountain in the world will be equal to the tallest one he has observed. We consider the biggest object of any kind that we have seen in our lives or hear about as the largest item that can possibly exist. And we have been doing this for millennia.

Taleb brings up an interesting point, which is that our documented history can blind us. All we know is what we have been able to record.

We think because we have sophisticated data collecting techniques that we can capture all the data necessary to make decisions. We think we can use our current statistical techniques to draw historical trends using historical data without acknowledging the fact that past data recorders had fewer tools to capture the dark figure of unreported data. We also overestimate the validity of what has been recorded before and thus the trends we draw might tell a different story if we had the dark figure of unreported data.

Taleb continues:

The same can be seen in the Fukushima nuclear reactor, which experienced a catastrophic failure in 2011 when a tsunami struck. It had been built to withstand the worst past historical earthquake, with the builders not imagining much worse— and not thinking that the worst past event had to be a surprise, as it had no precedent. Likewise, the former chairman of the Federal Reserve, Fragilista Doctor Alan Greenspan, in his apology to Congress offered the classic “It never happened before.” Well, nature, unlike Fragilista Greenspan, prepares for what has not happened before, assuming worse harm is possible.

So what do we do and how do we deal with the blindness?

Taleb provides an answer which is to develop layers of redundancy to act as a buffer against oneself. We overvalue what we have recorded and assume it tells us the worst and best possible outcomes. Redundant layers are a buffer against our tendency to think what has been recorded is a map of the whole terrain. An example of a redundant feature could be a rainy day fund which acts as an insurance policy against something catastrophic such as a job loss that allows you to survive and fight another day.

Antifragile is a great book to read and you might learn something about yourself and the world you live in by reading it or in my case re-reading it.

This piece originally appeared on Farnam Street.

Join over 60,000 readers and get a free weekly update via email here.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME Books

39 Books to Help You Make Decisions in Life

footprints-two-way
Getty Images

Shane Parrish writes Farnam Street

At Re:Think Decision Making in February, I asked participants to offer up some books on decision making. (If you’d like to be one of the first to know when I open up registration for Re:Think Decision making 2016 in Austin, TX , join the list.)

The crowd at the event was, in the words of one participants, the finest crowd you’ll find at a public event. These people are paid to make decisions for a living and want to find every edge they can. So when I asked them what books on decision making they read and recommend, you can bet they had a lot to say.

Here’s the list:

Decisive: How to Make Better Choices in Life and Work
By: Chip & Dan Heath

How to Measure Anything
By: Douglas Hubbard

How to Make Sense of Any Mess: Information Architecture for Everybody
By: Abby Covert

Wiser: Getting Beyond Groupthink to Make Groups Smarter
By: Cass Sunstein & Reid Hastie

The Surprising Power of Liberating Structures: Simple Rules to Unleash A Culture of Innovation
By: Henri Lipmanowicz & Keith McCandless

Gamestorming: A Playbook for Innovators, Rulebreakers, and Changemakers
By: Dave Gray, Sunni Brown & James Macanufo

The Righteous Mind: Why Good People are Divided by Politics and Religion
By: Jonathan Haidt

Yes or No: The Guide to Better Decisions
By: Spencer Johnson

The Little Book of Talent
By: Daniel Coyle

The Worry Solution: Using Breakthrough Brain Science to Turn Stress and Anxiety into Confidence and Happiness
By: Martin Rossman

Shantaram: A Novel
By: Gregory David Roberts

The Art of Living
By: Epictetus

The Education of a Value Investor
By: Guy Spier

Devil Take the Hindmost: a History of Financial Speculation
By: Edward Chancellor

Click: The Art and Science of Getting from Impasse to Insight
By: Eve Grodnitzky

The Dictator’s Handbook: Why Bad Behavior is Almost Always Good Politics
By: Bruce Bueno de Mesquita

The Back of the Napkin & How to Solve Problems and Sell Ideas
By: Dan Roan

Crossing to Safety
By: Wallace Stegner

Paradox of Choice: Why More is Less
By: Barry Schwartz

Streetlights and Shadows: Searching for the Keys to Adaptive Decision Making
By: Gary Klein

The Social Animal
By: David Brooks

The Laws of Simplicity
By: John Maeda

Nudge: Improving Decisions about Health, Wealth and Happiness
By: Richard H. Thaler

Reminiscences of a Stock Operator
By: Edwin Lefevre & Roger Lowenstein

This Will Make You Smarter
By: John Brockman

A more Beautiful Question: The Power of Inquiry to Spark Breakthrough Ideas
By: Warren Berger

Red Notice: A True Story of High Finance, Murder, and One Man’s Fight for Justice
By: Bill Browden

The Man who Mistook his Wife for a Hat
By: Oliver Sacks

Imprudent King: A New Life of Philip II
By: Geoffrey Parker

Seeking Wisdom
By: Peter Bevelin

Mastery
By: Rober Greene

Synchronicity: The Innes Path of Leadership
By: Joseph Jaworski

The Culture Map: Breaking Through the Invisible Boundaries of Global Business
By: Erin Meyer

Ubiquity: Why Catastrophes Happen
By: Mark Buchanan

Family Fortunes
By: Bill Bonner

Influence: The Psychology of Persuasion
By: Robert Cialdini

Antifragile: Things That Gain from Disorder
By: Nassim Nicholas Taleb

Poor Charlie’s Almanack: The Wit and Wisdom of Charles T. Munger
By: Peter D. Kaufman & Charlie T. Munger

The Brain that Changes Itself
By: Norman Doidge

And there you have it — a list of books on decision making that should give you a great starting point.

This piece originally appeared on Farnam Street.

Join over 60,000 readers and get a free weekly update via email here.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME psychology

The Trick to Memorizing an Entire Foreign Dictionary

Practice makes perfect

New Zealand’s Nigel Richards, who doesn’t speak French, has won the French-language Scrabble world championships. In the Scrabble world, Richards is considered to be the best player ever, having won the English world Scrabble championships three times, the U.S. national championships five times and the U.K. Open six times. His latest remarkable feat was achieved after reportedly memorising the entire French Scrabble dictionary in just nine weeks.

Richards is not the only person who has wowed the world with exceptional memory skills. Dave Farrow is the Guinness World Record holder for greatest memory. In 2007 he spent around 14 hours memorising a random sequence of 59 separate packs of cards (3,068 individual cards), looking at each card once. In 1981, Rajan Mahadevan recited from memory the first 31,811 digits of pi, a record that was astonishingly broken by Hideaki Tomoyori in 1987, who recited 40,000 digits.

For those of us struggling to remember what happened a couple of days ago, such innately superior memory capacity is remarkable. The question of whether these people are born with exceptional memory ability or acquire it by deliberate practice has interested both scientists and the general public alike for hundreds of years.

Memory genius comes with practice

Many books were published in the 1980s and 90s on the topic of genius and exceptional performance, with pioneering research comparing the superior performance of chess experts over beginners.

What became apparent, however, is that, although some people were able to recall large amounts of information seemingly effortlessly, their memory was truly exceptional only for materials that were specific to their expertise. In one study in the 1970s, William Chase and Herbert Simon at Carnegie Mellon University had world chess experts recall the configuration of chess pieces on a chessboard. When the chess experts were shown an actual chess positioned board, their recall of the pieces was far superior to novices. However, with random chessboards, players of all skill level had the same poor recall performance.

In order to answer the question of how to achieve exceptional memory performance, Chase, alongside K Anders Ericsson, developed the “skilled memory theory” which proposed three basic principles.

First, individuals need to rely on prior knowledge and patterns to encode and store the material in long-term-memory – what they called the “encoding principle.” Second, encoded information needs a “retrieval structure” – meaning it is associated with a cue when first seen so that it can be triggered during retrieval from long-term memory. And third, with additional practice people become more proficient in their encoding and can store the same amount of presented information in less time – the “speed-up principle.”

Techniques to try

What this is referring to is a mnemonic strategy. We are all capable of using such strategies although some of us are more skilled at it then others. The oldest and most common method is the method of loci (Latin for “places”). In the method of loci, the mnemonist first creates a series of places, imagined rooms (the encoding principle), then puts what is to be remembered in said rooms, and finally walks from room to room in a fixed order, to recall the material (retrieval structure principle).

The more familiar and elaborate the detail of the imagined place is, the faster they will be able to place and retrieval material (the speed-up principle). Many mnemonic methods such as loci require such visualisation. For example, digit sequences can be associated with word links. If 59 is “lip” and 47 is “rock”, then 5947 can be remembered by an interactive image of “lips kissing a rock.” Other mnemonic techniques include a digit-consonant system or converting digits into syllables (based on the Japanese language) which are then regrouped into words.

Although Richards is a somewhat reclusive figure, so we can’t say for certain what techniques he used, it is more than likely that he is highly skilled at mnemonic strategies, along with having an exceptional mathematical talent to play scrabble. He, and others like him are able to utilize mnemonic strategies beyond our comprehensible understanding. However, whether it is his dedication to practice or some innate superior memory that is responsible for this ability is still under scientific investigation.

This article originally appeared on The ConversationThe Conversation

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

TIME psychology

How to Avoid Getting Tricked By the Past

Shane Parrish writes Farnam Street

The fact that new information exists about the past in general means that we have an incomplete road map about history. There is a necessarily fallibility … if you will.

In The Black Sawn, Nassim Taleb writes:

History is useful for the thrill of knowing the past, and for the narrative (indeed), provided it remains a harmless narrative. One should learn under severe caution. History is certainly not a place to theorize or derive general knowledge, nor is it meant to help in the future, without some caution. We can get negative confirmation from history, which is invaluable, but we get plenty of illusions of knowledge along with it.

While I don’t entirely hold Taleb’s view, I think it’s worth reflecting on. As a friend put it to me recently, “when people are looking into the rear view mirror of the past, they can take facts and like a string of pearls draw lines of causal relationships that facilitate their argument while ignoring disconfirming facts that detract from their central argument or point of view.”

Taleb advises us to adopt the empirical skeptic approach of Menodotus which was to “know history without theorizing from it,” and to not draw any large theoretical or scientific claims.

We can learn from history but our desire for causality can easily lead us down a dangerous rabbit hole when new facts come to light disavowing what we held to be true. In trying to reduce the cognitive dissonance, our confirmation bias leads us to reinterpret past events in a way that fits our current beliefs.

History is not stagnant — we only know what we know currently and what we do know is subject to change. The accepted beliefs about how events played out may change in light of new information and then the new accepted beliefs may change over time as well.

This piece originally appeared on Farnam Street.

Join over 60,000 readers and get a free weekly update via email here.

TIME Ideas hosts the world's leading voices, providing commentary and expertise on the most compelling events in news, society, and culture. We welcome outside contributions. To submit a piece, email ideas@time.com.

Your browser is out of date. Please update your browser at http://update.microsoft.com