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Why some people can't tell left from right

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By Kelly Oakes12th January 2023

It can seem like an almost childish mistake, but a surprising number of adults confuse left from right and scientists are only just starting to understand why.

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When British brain surgeon Henry Marsh sat down beside his patient's bed following surgery, the bad news he was about to deliver stemmed from his own mistake. The man had a trapped nerve in his arm that required an operation – but after making a midline incision in his neck, Marsh had drilled out the nerve on the wrong side of his spinal column.

Preventable medical mistakes frequently involve wrong-sided surgery: an injection to the wrong eye, for example, or a biopsy from the wrong breast. These "never events" – serious and largely preventable patient safety accidents – highlight that, while most of us learn as children how to tell left from right, not everyone gets it right.

While for some people, telling left from right is as easy as telling up from down, a significant minority – around one in six people, according to a recent study – struggle with the distinction. Even for those who believe they have no issues, distractions such as ambient noise, or having to answer unrelated questions, can get in the way of making the right choice.

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"Nobody has difficulty in saying [something is] front and back, or top and bottom," says Ineke van der Ham, professor of neuropsychology at Leiden University in the Netherlands. But telling left from right is different, she says. "It's because of the symmetry, and because when you turn around, it's the other way around, and that makes it so confusing." 

Left-right discrimination is actually quite a complex process, calling upon memory, language, visual and spatial processing, and mental rotation. In fact, researchers are only just beginning to get to the bottom of exactly what's going on in our brains when we do it – and why it's much easier for some people than others.

Former US President Donald Trump was briefly flummoxed when leaders were asked to cross hands at a summit in the Philippines in 2017 (Credit: AFP/Getty Images)

HOW BEING LEFT-HANDED CHANGES YOUR BRAIN

 

Around one in 10 people are left-handed, and studies on twins have shown that genetics has a role to play. A study at the University of Oxford recently revealed four regions in human DNA that seem to play a role in determining if someone is left or right handed.

Those who were left-handed were found to have "mutations" in four genes that code for the body's cytoskeleton – the complex scaffolding that sits within cells to help organise them. Scans of people with these mutations showed that the white matter in their brains had a different structure. The left and right sides of the brains of left-handed people were also better connected than in right-handed people.

"Some individuals can tell right from left innately, just can do it without thinking," says Gerard Gormley, a GP and clinical professor at Queen's University Belfast in Northern Ireland. "But others have to go through a process." In an effort to understand what happens in wrong-sided medical errors, Gormley and his colleagues have conducted research on medical students' experience of making left-right decisions and examined the process.

"First of all, you have to orient right from left in yourself," he says. When the answer doesn't come instantly, participants described various techniques, from making an L shape with their thumb and index finger, to thinking about which hand they use to write, or strum a guitar. "For some people it's a tattoo on their body or a piercing," Gormley says.

Then, when figuring out which side is someone else's left or right, the next step is mentally rotating yourself so you're facing in the same direction as the other person. "If I'm facing you, my left hand will be opposite your right hand," says Gormley. "That idea of mentally rotating an object adds an extra degree of complexity." Other research shows that people tend to find it easier to judge if an image shows a left or right hand by imagining their own hand or body rotating.

Research published by Van der Ham and her colleagues in 2020 found that around 15% of people rate themselves as insufficient when it comes to identifying left and right. Almost half of the four hundred participants in the study said they used a hand-related strategy to identify which is which.

The more asymmetrical someone's body is – in terms of writing hand preference, for example – the easier they find it to tell left and right apart

The researchers used something called the Bergen right-left discrimination test to dig deeper into how these strategies work. Participants looked at pictures of stick people either facing toward or away from them, with their arms in various positions, and had to identify their highlighted hand as their left or right. "It seems simple, but it's kind of frustrating if you have to do a hundred of these as quickly as you can," says Van der Ham.

In the first experiment, the participants sat with their hands on a table in front of them. "There was a very clear effect from how this little stick figure was positioned," says Van der Ham. "If you were looking at the back of the head, so it was aligned with you, people were a lot faster and more accurate." Similarly, when the stick person was facing the participant but had their hands crossed, so their left hand was on the same side as the participant's left hand, people tended to do better.

"That tells us that the body really is involved in this," says Van der Ham. The next question was whether participants were using cues from their body at the time of the test to identify left and right, or referring to a stored idea of their body instead.

To answer that, the researchers repeated their experiment, but this time tested four different scenarios: participants sat with their hands either crossed or uncrossed on the table in front of them, and had their hands either visible during the test, or covered with a black cloth.

But the researchers found that none of those changes influenced test performance. In other words, participants didn't need to actually see their hands in order to use their own body to distinguish right from left.

"We haven't completely solved the issue," says Van der Ham. "But we were able to identify our bodies as being a key element in identifying left from right, and that we consult our body representation as we have it in a more static way."

Mistakes made during medical procedures due to left-right errors have led some surgeons to take extra steps to ensure they operate in the right place (Credit: Tommy London/Alamy)

In Van der Ham's experiments, the boost in performance that came from being in line with the stick person was more pronounced in people who said they use a hand-related strategy to tell left from right in their daily lives, as well as in women generally. The researchers also found that men tended to be faster in responding than women, but the data did not back up previous research showing that men perform better overall in left-right discrimination tests.

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Exactly why people differ in their ability to tell left from right isn't clear, though research suggests that the more asymmetrical someone's body is (in terms of writing hand preference, for example) the easier they find it to tell left and right apart. "If one side of your brain is slightly larger than the other, you tend to have a better right-left discrimination," says Gormely.

But it could also be something that we learn in childhood, like other aspects of spatial cognition, says Van der Ham. "If kids are in charge of finding the way around, if you just let them walk in front of you for a couple of metres and make the decisions, those are the kids that ended up being better navigators," she says.

Research by Alice Gomez and colleagues at the Lyon Neuroscience Research Center in France hints that left-right discrimination is something that children can pick up quickly. Gomez designed a two-week intervention programme, delivered by teachers, designed to increase five-to-seven-year-olds' body representation and motor skills.

When they were tested on their ability to locate the correct body part on themselves or a partner – their right knee, for example – after the programme, the number of left-right discrimination errors were almost halved. "It was very easy for us to increase the abilities of children to be able to locate the [body part] on the basis of the name," says Gomez.

One reason for this might be that the children were taught a strategy – to think about their writing hand – for when they couldn't remember right and left. The programme's focus on children's own bodies is another possible explanation, especially as other research shows that an egocentric reference frame is key when we make left-right decisions.

In a typical classroom, children might label body parts on a diagram rather than their own bodies, because the latter is more time-consuming and difficult to assess for a teacher, says Gomez. "It's very rare that they will have the time to be egocentric," she says.

Most of us can distinguish up and down intuitively, but working out left from right can take more mental gymnastics (Credit: Alamy)

While there are plenty of everyday scenarios where knowing left from right is important, there are some situations where it's absolutely critical. Brain surgeon Marsh was able to put right his wrong-sided trapped nerve surgery – but a surgeon removing the wrong kidney or amputating the wrong limb, for example, would have devastating consequences.

Medicine is not the only field where left-right errors can make the difference between life and death: it's possible that a steersman turning the ship right instead of left was a contributing factor in the sinking of the Titanic.

But while some people have to put in more effort to judge left and right, everybody has the ability to get left-right decisions wrong, says Gormley. He hopes that more awareness of how easy it is to make such a mistake will lead to less stigma for those who need to double check their decision.

"As health care professionals, we spend a lot of time labelling spatial orientations: proximal, distal, superior, inferior, but really pay no attention to right or left," he says. "But actually, of all the spatial orientations, that is the most challenging."

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December 18 - It's Chanukah Time


What's Up?

In the spirit of the season we are presenting special editions of holiday news. Here's Chanukah. (Santa will slide down your PJT chimney soon).


Hanukkah or Chanukah In Hebrew, the word Hanukkah is written חֲנֻכָּה or חֲנוּכָּה (Ḥănukā). It is most commonly transliterated to English as Hanukkah or Chanukah. Both are considered correct, though Hanukkah is the most widely used spelling, while Chanukah is more traditional. Often called the Festival of Lights, the holiday is celebrated with the lighting of the menorah, traditional foods, games and gifts."

"The eight-day Jewish celebration known as Hanukkah or Chanukah commemorates the rededication during the second century B.C. of the Second Temple in Jerusalem, where according to legend Jews had risen up against their Greek-Syrian oppressors in the Maccabean Revolt. Hanukkah, which means “dedication” in Hebrew, begins on the 25th of Kislev on the Hebrew calendar and usually falls in November or December.


Hanukkah 2022 begins on the evening of Sunday, December 18 and ends on the evening of Monday, December 26.


 

A PJTime Creative Tutorial on How to Light Up YOUR Life


This simple exercise can help you Improve overall mental and physical health by releasing "positive neurochemistry" to shift negative mindsets and savor the small things that light up your life. Whether you celebrate Chanukah or not try this!


1. Find a vessel that appeals to you. Any container to hold your "light". 2. Date 8 separate slips of paper and each day write down:

  • Something kind someone has said to you - it can be as simple as a "Thank You"

  • A quote you find inspiring or meaningful

  • An event you've witnessed, experienced or heard about that is positive or inspirational

  • Memories you cherish or make you smile

  • The names of family members, friends, pets, or people who you like (love is not even the criteria)

  • An author, famous figure, colleague, you find admirable, inspiring or has done something to make this a better world.

  • The happiest moment of your day

There's no right or wrong, just as long as it's something or someone who lights up the your life

3. Sharing - Each evening, after lighting your menorah candle* read out loud (even to yourself if celebrating alone or family members) your "light" of that day. *If you don't celebrate Chanukah at the end of each day or week or special celebration. LIGHT IS NON-DENOMINATIONAL!

Benefits on mental health

Focusing on the small and large things that are easy to get buried in in the negative news cycles in the media, living in a time of pandemics, famine and war. Whether consciously aware, negativity, in all its forms can contribute to feelings of helplessness, hopelessness and despair - all hallmarks of depression.

 

with Andrew Huberman's guidelines to improve your gut biome after you've indulged in traditional Chanukah food* . . . Oy Vei!

"We all have trillions of microorganisms living inside our gut—not just our stomach but our intesti­nes and throat and mouth, and on our skin, in our eyes and nasal passages. Maybe that sounds bad or gross, but… it turns out these microbiota are essential for our immune, brain and hormone health—in part because they make chemicals that immediately impact how the rest of our body functions, including neurotransmitters like serotonin. The bottom line is: we need to nurture these living microbiota cargo to best support our mental and physical health."

"Microbiota diversity is a measurement of the number of different species of microbiota in our gut. Low diversity is considered a marker of dysbiosis (microbial imbalance) and has been associated with autoimmune diseases, obesity and cardiometabolic conditions. Below, I summarize 6 tools that can help increase microbial diversity and improve overall gut and thereby, body and brain health."

Fermented Foods Help Your Gut

Dr. Sonnenburg discussed the findings of his recent human study, in collaboration with Dr. Chris Gardner of Stanford, in which they investigated whether diets high in plant-based fiber or fermented foods would influence the health of the gut microbiome. Their results show that fermented foods increased overall gut microbiota diversity, as well as reduced key markers of inflammation.

​In the study, participants ate six servings per day of fermented foods, however, higher total amounts of ingested fermented foods did not lead to further benefits. Instead, consistently incorporate fermented foods into your daily diet to achieve better outcomes for gut microbiome health and inflammation reduction.

"Try incorporating low-sugar fermented foods into your diet, such as sauerkraut, plain yogurt, kimchi, kombucha, natto, kefir or even drinking brine. Find these products in the refrigerator section to ensure there are live active cultures. (Shelf-stable fermented foods are pasteurized, therefore, will not offer the same boost to the gut microbiome.) Also, there are cost-effective ways to make your own fermented foods, such as kombucha or sauerkraut, at home"


What About Fiber?

"In this study, a high-fiber diet did not lead to an increase in microbiota diversity. However, high-fiber diets did increase the amount of carbohydrate active enzymes which help digest fiber and could further enhance the microbiome's ability to degrade other complex carbohydrates. Additionally, some participants in the high-fiber group showed a reduction in markers of inflammation. Plant-based, high-fiber foods (i.e., vegetables, legumes, and whole grains) offer significant benefits for overall health and can help provide key nutrients for established microbiota."


Prebiotics, Probiotics and Syn?

​Prebiotics: fermentable dietary fiber or microbiota-accessible carbohydrates; supplements of food for established gut microbiota

​Probiotics: live bacteria or yeasts that can colonize in the gut microbiome

Synbiotics: mixtures of prebiotics and probiotics

"Augmenting the gut microbiome with low levels of prebiotics and/or probiotics while still focusing on eating whole quality foods leads to improvement in gut microbiome health."

"In cases of dysbiosis, such as after taking antibiotics, during high periods of stress, traveling or changing your diet, higher levels of prebiotics and/or probiotics can aid in recovery and replenish your gut microbiome. However, the excessive intake of probiotics has been linked to the induction of brain fog; therefore, if you experience these symptoms, you could try to reduce the level of supplements that you are ingesting."

"Since prebiotics and probiotics are considered supplements, they are not FDA-regulated products. When choosing a supplement, look for an independently validated product. Finally, the gut microbiome is uniquely personalized. Therefore, supplementation will impact individuals differently."

Straight From the Farm is Best

Foods additives are ubiquitous in processed foods. Emulsifiers, detergent-like additives, can disrupt the mucus layer of the GI tract. In animal models, emulsifiers reduce microbial diversity, induce low-grade inflammation, and cause an increase in body fat, higher blood sugar levels and insulin resistance - key markers of metabolic syndrome.

The typical Western Diet (i.e., high fat, low fiber, higher in processed foods) does not provide gut microbiota with many of the key essential nutrients. When you eat complex, plant-based fiber, the gut microbiota produces fermentation by-products, such as short-chain fatty acids (e.g., butyrate). These substances reduce inflammation, help maintain the gut's mucosal barrier, regulate the immune system, and modulate metabolism along the GI tract. To enhance the health of your gut microbiome, prioritize a diet rich in whole foods, plant-based fiber, and fermented foods.

FYI - Use Real Sugar- only 49 Calories per Tablespoon

"Clinical studies have yet to fully tease apart the impact (if any) that artificial sweeteners have on the gut microbiome. However, within animal models, there is evidence that artificial sweeteners can disrupt the gut microbiome. A recent study showed that neuropod cells in the gut can discriminate between natural and artificial sweeteners. Further, these cells send a unique pattern of signals to the brain, depending on whether the sugars they sense are nutritive (i.e., contain calories) or are non-caloric sweeteners.z'

*"Non-caloric plant based sweeteners like stevia are probably fine, but there have not been many studies of stevia in regards to the microbiome." Keep it Not Too Clean!

"Microbiota are present on any and all surfaces which have come into contact with the environment. Dr. Sonnenburg notes, "Exposure to microbes from the environment is likely an important part of educating our immune systems and keeping everything in the proper balance." The gut microbiome is also populated from social interactions, including skin contact by shaking hands, hugging, kissing etc. and interactions with pets and dirt, and grass. Over-sanitization of our environments or excessive use of antibiotics can eliminate sources of good gut microbiota. While it is still important to eliminate the introduction of disease-causing pathogens and harmful environmental chemicals (e.g., pesticides), consider that many environmental microbes play an integral role in the establishment and maintenance of a healthy gut microbiome." Andrew Huberman, Ph.D., is a neuroscientist and tenured Professor in the Department of Neurobiology at the Stanford University School of Medicine. https://hubermanlab.com/

 

to know about *Traditional Chanukah foods* . . . Oy Vei


"A typical Chanukah menu sounds as though it were planned by the under twelve crowd— potato pancakes, fried, of course, in lots of oil. Sweet cream cheese rugelach. Strawberry-jam-filled doughnuts (sufganiyot), covered in powdered sugar. Fried apple fritters. Cheese-filled doughnuts fried in oil and dipped in honey. Cheese blintzes." "Is it all just a ploy to keep kids lingering around the candles and enjoying a family meal? Not at all! Chanukah food traditions have their origins in the first years that the holiday was celebrated, and are meant to remind us of certain miracles associated with the events of Chanukah itself. And of course, remembering the miracles and the freedom that we're all celebrating adds a special flavor to everything we serve."

Why do Jews eat fried foods during Chanukah?

"Most of us are familiar with the miracle of the oil— that one day's supply of oil lasted for eight days. And we know this is the origin of the mitzvah to light the menorah for eight days. It is also the reason why we have the custom of eating foods cooked in oil."

"There are deeper connections between olive oil and Chanukah."

"Mystically, both the menorah and the oil used to light it are associated with Chochmah, wisdom. The war between the Greeks and the Jews was also a war over whose wisdom would endure. The Greeks wanted everyone under their rule to think and study exactly as they did. They were violently opposed to the idea of G‑dly wisdom, and so forbade the study of Torah."

"Also, the word shemen, Hebrew for oil, contains the same letters as shemoneh, eight, the number of days that the miracle of the oil lasted." Read more? Click here: Chabad Chanukah recipes and traditions.

 

We believe in equal equal opportunity so here's a recipe from GlitterInc.com to compliment Melted SnowMen Truffles on December 1st PJTime


How to Make Chanukah OREO Cookie Balls which are NOT tradition . . .

INGREDIENTS

1 pkg. (8 oz.) brick cream cheese, softened 42 OREO Cookies, finely crushed (about 3-1/2 cups), divided 1 pkg. (12 oz.) white melting chocolate*, melted Blue Sprinkles

DIRECTIONS

  1. Mix cream cheese and cookie crumbs until blended.

  2. Put your chocolate in a microwave-safe bowl and melt chocolate in the microwave by cooking about 15 seconds at a time, removing from microwave, stirring, and microwaving another 15 seconds. Repeat this until your chocolate is completely melted and smooth. (You can also melt your chocolate in a pot on the stove.)

  3. Shape mixture into 48 (1-inch) balls. Freeze 10 min. Dip balls in melted chocolate; place in single layer in shallow waxed paper-lined pan. While the melted chocolate is still soft, sprinkle with your favorite holiday sprinkles.

  4. Refrigerate 1 hour or until firm. Keep refrigerated until ready to serve.

*You can also use semi-sweet or milk chocolate baking chocolate if you prefer a different kind of chocolate.

Recipe adapted via Snack Works

TIP: To easily coat your OREO cookie balls with the melted chocolate, add the cold cookie balls, one at a time, to the bowl of melted chocolate. Use 2 forks to roll the cookie balls in chocolate until evenly coated. Remove balls with forks, letting excess chocolate drip back into the bowl and place the coated balls onto your prepared pan. Don’t forget to refrigerate the balls until firm.

You could fry them!

Have Oreo Cookie Balls with a glass of milk. You'll have to decide if it's kosher!

 

When my brother and I were growing up Chanukah was simple: Eight evenings of saying prayers while lighting a candle and getting 8 small presents each night. The present part, I suspect, was so we didn't feel left out of our Christian peer groups. Today there are decorations, and Chanukah "trees", designer menorahs, parties and expensive presents . . . besides the latkes. Judy



Eight Ways tor a stress free Chanukah If you've followed us for any length of time you know we focus on mind-body-spirit well being. In that spirit we offer these suggestions so your Chanukah "spirit" isn't overwhelmed:

1. Give thanks for cleaning up candle wax and not pine tree needles.

2. Get "lit" before you light menorah candles

3. Stay in a 5-star hotel for 8 days and nights.

4. Use credit cards instead of gelt

5. Instead of gambling with a dreidle at home go to Vegas where the odds of are higher

6. Don’t give presents, do good deeds

7. Go to bed on Thanksgiving and wake up on New Years.

8. Bake potatoes instead of grating them to death

9. Eat macaroons with Ben & Jerry

 

Happy Chanukah & Sanity to all our Friends! You can wish someone a happy Hanukkah by saying chag sameach, which is pronounced [ khag sah–meh-ahkh ]. This expression means “happy holiday

 

Copyright © 2022, Peggy Arndt and Judy Westerfield, All rights reserved.

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It takes 1/4 of a second-- the "secret" to stop anger in its tracks

I met some remarkable people working as a therapist in a hospital psychiatric ward. One of the most memorable was a Vietnam veteran who flew into rages. He'd lost his lower left leg in battle. But the war or being severely injured were not what made him rageful. He had always raged, even as a child. His father raged as well.

His wife was the main target of his rages. He would become uncontrollably angry at the smallest of things like forgetting where she left her keys, or spilling a beverage . . . until he learned the "1/4 second secret" to controlling unwanted anger.

To understand the 1/4 of a second secret you need to understand the fight or flight reaction.




We have an ever vigilant watchdog, a small almond shaped organ in our midbrain called the amygdala (amygdala from the Greek word for almond) that looks out for us 24/7 and alerts us to any POSSIBLE threat.

When our brain receives a threat-cue, sounds, sights, smells, touches or even our imagination, our brain wants FAST action. No waiting around for a sign of safety, no thinking things through just FLEE or stay and FIGHT (there is also a "freeze" response but that's another post).

Our amygdala floods the cells in our body with neurochemical signals to increase blood pressure, raise heart rate, send blood away from major organs to your muscles, constrict capillaries near the skin, increase breathing, and tamper down anything that isn't crucial to fight or flee for survival.

Unfortunately, our brain doesn't discriminate between real threats, imagined threats, conditioned or potential threats. That's why things that are, in reality, not threatening can become threat-cues.

Luckily, many people tend to go with flight more easily than fight. But for those whose brain directs them to fight here's the "1/4 second secret" that stopped the vet's rages:



The thinking part of our brain, the prefrontal cortex, can STOP the fight or flight response. We have 1/4 of a second to interrupt the signal from the threatening stimuli (sounds, sights, smells, touches or our imagination). In that 1/4 split second tell the amygdala "Stop" or "I'm safe" and take a deep breath.

If we don't "catch it" in 1/4 of a second a neurochemical cascade will flood our cells. Once the cells are flooded it takes 15 - 20 minutes for the neurochemicals to metabolize out of our body (provided no new information saying the threat continues to exist is received).

This is what the vet learned to do:

  • First, he identified the triggers that sent him into a rage.

  • Second, when he anticipated a trigger he used his pre-frontal cortex to say "stop" to the amygdala.

  • Third, if he failed to anticipate the trigger and felt the stress response building he would take a 20 minute walk to speed up metabolizing out the stress response.

I admired his remarkable determination. It took him 1/4 of a minute at a time to stop his rage response, change his marriage and improve his life.

Do you have a "secret technique" to control your stress response?

(PA) #anger

Are we hard-wired to be lazy?


My earliest memory was my mother waking me up. It was dark outside and chilly inside. I don't remember how many times she came into my room to get me out of bed. I do remember pulling the covers over my head and refusing to get up in the dark and cold to get ready for pre-school . . .

Mom was the first to give up in our morning battle and I started kindergarten with "learning deficits". Decades later I continue to not want to greet the new day until it is DAYtime. Morning and me ain't buddies.

Furthermore, people, like my husband, who bound out of bed alert and cheerful are jarring at best and obnoxious at worst.

I take umbrage at being labeled "lazy" by you early-morning-worshipers who think those of us who understand that moving any extremity in increments larger than a few inches is not natural before 10 am.

NOW! FINALLY I'm vindicated!!! Read this excerpt!

"As anyone who struggles to get out of bed in the morning knows, fighting laziness is a losing battle. From beneath the covers, the world outside seems colder; the commute to work seems longer; the number of e-mails to answer unbearably high. Authority figures may chalk our lethargy to lack of self-discipline, but . . .




. . . new research suggests that we’re just being our true selves: Choosing the path of least resistance, scientists argue, is hard-wired into our brains." (What a relief. I thought my wiring was simply "lose")

"Outlining the results of their work in a new paper in eLife, the researchers conclude that human brains seem to be wired for laziness. “Our brain tricks us into believing the low-hanging fruit really is the ripest,” said lead author Nobuhiro Hagura, Ph.D.,. . . ”

"When we make decisions to act (or not), the brain thinks like an economist and runs a cost-benefit analysis. If the “cost to act,” as the researchers call it, is too high, it can bias our decision-making process, making us less likely to do things.


Applied cleverly, their findings can help us do things that we should be doing — and those that we should be avoiding. For example, going to the gym in the morning could seem more effortless if you sleep in your sweats, just as stashing your booze on a hard-to-reach shelf might make drinking it seem like more effort than its worth. There’s no guarantee that these hacks will work, but . . . "

". . . if there’s one thing we can count on, it’s that we’ll always take the easy route when it’s available — and becoming less lazy may simply come down to avoiding that option altogether."


If you don't believe us read the article:

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