The human body is an impressive thing. Without any external cues, it knows how to shiver, sweat, breathe, chew, swallow, digest, heal, rest, circulate blood, formulate thoughts, and, well, roughly a million other things. The human body, to put another way, is a collection of minute calculations, accumulated over 50,000 years and honed into the biological supercomputer it is today.
But sometimes the human body is too advanced for its own good. Sometimes, that internal code will force it to do things without you even realizing it. And other times still, it’ll go so far to do the precise opposite of what you want it to. (Have you ever felt physically ill when you were sad? Tried to focus and inadvertently became even more distracted? Tasted color? Yeah, that sort of thing.)
Herein, to alleviate any concern you might feel when these events go down, are the 30 most common ways your body tricks you and works against you—each and every day. And for more anatomy anomalies, check out the 50 Secret Messages Your Body Is Trying to Tell You.
Your eyes can make you hear things.
Your senses interact in surprising ways, sometimes enhancing your experiences of the world. But other times, they can also mislead you. That’s the case of the McGurk effect, in which seeing something can lead you to hear the same audio differently. For example, in a study where people were played audio of the phrase, “he’s got your boot,” they were more likely to hear “he’s gonna shoot” when shown a video of a man pursuing a woman at the same time.
You can taste colors.
Just as sight misleads us about what we hear, it can do the same with what we taste. If something “looks” like it is going to taste a particular way, we’re more likely to taste it that way. For example, one study of wine enthusiasts found that connoisseurs used vastly different terms to describe the flavor of a white wine and the exact same wine that was colored red. And to learn more truths locked away in your biology, check out the 15 Things That Happen to Your Body When You Don’t Get Enough Sleep.
And color can change temperature perception.
Color can also affect the way we experience temperature. For example, when subjects in an experiment were served the same drinks in different colored containers, they perceived the liquid in red and yellow containers as hotter than liquid in blue and green containers. Crazy, right?
Driving blinds you.
While driving we tend to blot out images on our periphery, in a phenomenon known as “motion-induced blindness.” It’s believed to grow out of the brain’s attempt to discard unimportant information, focusing, say, on the road in front rather than pedestrians on the sidewalk or passing storefronts. The longer we stare at an object in front of us, the more likely we will fail to see objects in our peripheral vision. And if you’re curious where this phenomenon might strike most often, check out the The Busiest Road in Every State.
Fake appendages feel real.
This is weird, but we can actually forget where our real limb went when it’s hidden from view and a fake one put in its place. For example, in this video, a woman is shown a fake rubber hand next to her real one, which has been hidden. When both hands are touched at the same time, she thinks the fake one is her own. In studies, the hand’s temperature will even drop as the brain “forgets” about the real one.
And phantom limbs do exist.
For those who have actually lost limbs, there is the odd but better-known phenomenon of phantom limb syndrome, in which they still feel pain, pressure or other sensations in a body part that is no longer there.
Your feelings shape the world around you.
We’d like to imagine that we view the world through an objective lens and can trust what we see. But researchers have found that, in fact, the way we feel tends to filter the way we interpret the world—which may be “rose-colored glasses” or a “half-empty glass” or based on other feelings of fear, surprise, or hunger. Psychologists call this “affect heuristic” and it’s a way our brains filter information to make decisions quickly, but can often overlook much that is right in front of our eyes. And for more hidden body messages, see What Happens to Your Body on an Airplane.
When the background changes, you see objects at different sizes.
The exact same object can appear larger or smaller depending on the context surrounding it. (That message on your car mirrors is an everyday example of this.) This was the discovery of Italian psychologist Mario Ponzo, after whom this phenomenon, the Ponzo illusion, is named. A classic example is this one, in which the identical yellow line looks larger or smaller depending on where it sits with respect to other geometric shapes.
Emotional pain can cause physical pain.
While heartbreak is primarily an emotional experience, our body actually feels it. As Ethan Kross of the University of Michigan’s Emotion & Self Control Lab tells The Washington Post, “A social rejection hijacks the part of our brain that signals pain to say, ‘Hey, this is a really serious situation,’ because just like physical pain, the consequences could be there.” It’s a physical response that is alerting us to avoid that kind of emotional pain.
Your brain thinks about exactly what you don’t want it to think about.
The “ironic process theory” holds that deliberately trying to suppress certain thoughts makes us more likely to think them. As the classic example goes, if we tell ourselves not to think about a pink elephant or white bear, that’s what pops into our mind.
During times of focus, your mind wanders.
Similar to thinking about things we are trying to suppress, trying to focus tends to result in our mind wandering. This is especially true when switching between different tasks, creating what is known as “attention residue.” This condition was described by Sophie Leroy, assistant professor of business at the University of Washington, to Time this way: “Let’s say I work on a project right up until I have a meeting. I may be at the meeting, but my brain is still trying to find closure on that project I was working on, so questions and ruminations about that project are interfering with my ability to concentrate.”
Also, practitioners of meditation know this feeling all too well. When you want to focus, your mind wanders. When you let your mind wander, it focuses. So frustrating!
Noise affects how your food tastes.
In another example of how one sense can misdirect another, research has found that sound can actually change the way something we are eating tastes. For example, when background noise is high, it can be hard for individuals to accurately determine how sweet or salty the food they are eating may be.
Dieting can become a withdrawal.
Even when you convince yourself to kick a bad habit, or try to adopt a good one, sometimes your body has other ideas. That’s most obvious as you kick off a diet. You may cut out high-fat foods and hefty carbs, only to feeling anxious, unhappy and eager to eat the stuff you know is bad for you. Scientists have found that changing from a high-fat to low-fat diet results in similar effects as drug withdrawal in mice—a lesson that can also be applied to people. And if you need help breaking any habit, learn the 40 Science-Backed Ways to Kick Old Habits.
That brings up one of the cruelest ways that bodies can trick their owners—drug withdrawal. Though a person may be hurting themselves with cocaine, heroin or just alcohol, cutting it out of their behavior is not just difficult because of their mental dependency on it, but how their body reacts to being without it. From flu-like symptoms to tremors to seizures, a body can react in extreme ways when the controlled substances it’s used to receiving are cut off—convincing its owner to continue doing things they know they shouldn’t.
Skipping meals makes you eat more overall.
While some dieters might think that skipping a meal would be an effective way to cut back on calories, in fact it has been found to have just the opposite effect, as your body convinces you that you are starving and need to eat even more than you regularly would. A study of mice that compared those that ate food only one time a day and another group that ate continuously, found the former actually put on weight over the long term.
Cutting carbs can backfire.
While cutting back on carbs (or cutting them out completely) is a reliable way to lose weight in the short term, it can backfire as soon as any carbs are brought back into your diet. When you cut them out, your body will react with a drop in energy and low blood sugar, driving you to return some carbs to your diet, and watch your body immediately pack on more pounds.
Diet soda spurs obesity.
Another cruel way our body can outsmart our dieting efforts is the way it reacts to our drinking diet soda. While drinking calorie-free beverages would seem like a healthy alternative to the usual sugary drinks, in fact diet-soda consumption has been linked with obesity. This may be because the artificial sweeteners trigger the body to expect calories from the sweet and when it doesn’t receive it, it spurs you to find those calories elsewhere (raiding the snack drawer or ordering a dessert you don’t need).
Fat-free food makes you gain weight.
Like diet sodas, we can try our best to outsmart our body with fat-free food, but it can find a way to get us to eat fat anyway. Research has found that subjects who ate non- or low-fat dairy ended up eating more carbs throughout the day than those who just ate whole-fat dairy.
Skipping food puts you in a funk.
Trying to change health habits can be an emotionally exhausting experience. Researchers at MIT found that carbohydrates don’t just give a body energy but stimulate the production of serotonin—which helps explain why your body convinces you to order that extra chocolate chip cookie. When you don’t maintain a certain level of carbs, you may find yourself in a rotten mood.
It moves you to tackle unimportant tasks.
You may have a long list of to-do items like “apply for a better job” or “look into moving to a new city” or “write the Great American Novel,” but somehow these longer-term goals get sidelined by daily errands and mundane work tasks that are hardly the sorts of things you will view as the things that mattered in your life. This is due to a phenomenon called the “urgency effect,” in which your brain prioritizes immediate satisfaction over long-term rewards—such as meeting a short-term deadline versus making progress on a project with no deadline at all.
It demands sugar when you don’t need it.
When your glucose levels are low, the parts of your brain associated with reward get active, making you think how delicious food will be, balanced by your prefrontal cortex, which tells you that eating a bunch of sweets is a bad idea. In studies of the obese, even when hunger wore off, the brain’s reward centers remained active, convincing study participants that they needed to keep eating food they really didn’t need.
Your fat-fighting cells sometimes just give up.
Part of why it’s so hard to lose weight once you put on the pounds is that your own fat-fighting cells surrender once you reach a certain amount of weight. Specifically, the immune cells known as invariant natural killer T-cells, which monitor metabolic activity and help prevent obesity don’t increase when your weight increases. In other words, when you’re at a healthy weight, your fat-fighting cells help you stay there. But once you put on the pounds, all bets are off. To counteract that, read up on the 100 Motivational Weight-Loss Tips for Summer.
You’re influenced by decoys.
When we are presented with two choices and a third one is added, it can affect our preference between the first two. For example, if given a choice between a small- and medium-sized beverage, we may be likely to select the small—until a large beverage gives all three sizes new context, leading us to more often than not select the medium size instead. This is known as the “decoy effect.”
You see detail even if it doesn’t exist.
Looking around a room, we can believe that everything is in sharp focus, but in fact what the eye takes in is often blurry and our brain fills in the detail. In one study, described by Medical Daily, researchers “watched participants’ eyes with a camera capable of recording 1,000 images per second. As their eyes made quick movements, known as saccades, the researchers quickly changed objects in their field of view. As these objects changed the participants were asked to describe the them as they stood in their peripheral vision—they found that the descriptions were largely based on previous notions of what they could be, kind of like a template for the object from our memory, confirming our brains trickery every time we look around the room.”
You react like a (metaphorical) ostrich.
Our minds can drive us to respond to unpleasant or uncomfortable things in life by avoiding them completely or acting like nothing is wrong. This conflict avoidance, known as the “ostrich effect” because it involves figuratively burying our heads in the sand, can feel good over the short term but create long-term damage as risks we ignore become realities.
Your body weight fluctuates—by the day.
While it’s a good idea to keep an eye on your weight with the occasional check-in at the scale, anyone who makes too regular habit of it knows how your weight can be deceptive. You may seem to be making progress in weight-loss efforts in the morning only to see your weight pop up by a pound by the evening. This is often explained with changes as your body excretes water and will be shed the next day, but it’s easy to let our body convince us otherwise.
Smelling activates your hunger.
Our noses have evolved over millennia to be extremely sensitive and responsive to the smell of good food. But research has found a correlation between obesity and a strong sense of smell. As the study’s author said, “It could be speculated that for those with a propensity to gain weight, their higher sense of smell for food related odors might actually play a more active role in food intake.”
Your taste buds make you overeat.
Not because food tastes good, but because you can’t taste it as well. While overeaters tend to have stronger senses of smell, research has actually found that they often have weaker senses of taste—leading them to eat more food in order to experience the same taste enjoyment. That was the finding of a study that gave obese and non-obese children different taste strips to lick and identify, rating the amount of flavor from 0 to 20. The heavier kids scored the flavor at an average of 12.6 compared to the non-obese kids, who experienced an average of 14 on the flavor scale.
You think you have more control than you do.
The “illusion of control” is the way our mind overestimates how much influence we actually have on a particular situation, whether beating ourselves up for not doing something differently or imagining we had a greater impact on an outcome than we possibly could have.
Do the Opposite of What We’re Told
For many, our minds respond to being told what to do, whether it’s by a doctor with our best interest in mind or a boss who asks us to do stuff we know is not worthwhile. It’s a phenomenon called “reactance,” in which the feeling that choices are being removed leads to an almost subconscious rebellion and attempt to do the thing we aren’t supposed to in order to prove we have freedom of choice. And for more fascinating stories about your body, learn the 20 Ways Our Bodies Will Be Different in 100 Years.
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