Ever since René Descartes, scientists and philosophers have wrestled with the relationship between our minds and our bodies. Today, science and medicine typically assume that our mental processes take place in the head, not the body. But our physical bodies, abilities, and motions actually can bias the conclusions drawn by our mental machinery in strange ways, according to a growing body of research by Jessica Witt at Colorado State University and other psychologists who study human perception and cognition. Our bodies tweak our perceptions in a fascinating range of unexpected ways. 

1. IF YOU'RE ON A HOT STREAK AS A HITTER, THE SOFTBALL LOOKS BIGGER TO YOU.

All kinds of athletes experience visual distortions along these lines, as research by Witt and many others has shown. Football uprights also look wider to people who are good field-goal kickers; tennis aces see the net as lower; targets appear larger to the best dart throwers; people experienced in parkour see walls as lower than novices; and better golfers see those 18 holes on the green as larger. This bias cares nothing for your opinion that you're a jock. It only shows up if you actually play well.

2. OBJECTS LOOK CLOSER AND SMALLER IF THEY ARE EASIER TO REACH AND GRASP.

So you're not an athlete. Physical biases to perception can creep in when you're reaching for the TV remote, too. University students in experiments done by Witt and Dennis Proffitt show that people perceive an out-of-reach object as closer if they are given a baton to hold to help them reach it. Not only does having a real baton in your hand help to make it seem like an object is closer than if you get no assist, but simply imagining that you could use a baton shortens your perception of the distance to the object, Witt and her colleagues found in a separate set of experiments. This scaling effect even works on objects almost 100 feet away if you shine a laser pointer on the object or just imagine doing so.

3. HILLS LOOK STEEPER WHEN YOU'RE OBESE, OUT OF SHAPE, OR WEARING A BACKPACK.

Body biases on perception can mess with our fitness goals. Experiments done by Witt, Mukul Bhalla, Dennis Proffitt and others find that people perceive a target as farther away if any extra effort is required to walk, throw, or jump to it. Specifically, subjects wearing a heavy backpack judged that a slanted surface before them was 5 degrees steeper than unencumbered subjects. Similarly, people who are tired or less fit also overestimate steep grades compared with rested or fit folks. It's as if the body warns the mind to scale back its plans in order to protect us from tough tasks. But now that we don't live in the wild, that protection might not be doing us any favors.  

4. UNDERWATER TARGETS LOOK BIGGER IF YOU WEAR FINS RATHER THAN SWIM BAREFOOT.

So, exertion changes how we see the world on land. What about "at sea," or at least in a swimming pool? The exertion distortion influenced how flippered subjects recruited at a pool saw underwater targets compared with barefoot swimmers, Witt and her colleagues found. After swimming either barefoot or wearing fins, subjects stood on submerged steps and stuck their heads underwater to look at targets and estimate their distance. They weren't even swimming at this point, but just wearing fins made the target seem closer. Better swimmers also estimated that the targets were closer. By extension, better swimmers probably see the same shore as closer than weaker swimmers. So either train up or gear up, or both, if you're out in open water.

5. ACHES AND PAINS CAN MAKE DISTANCES LOOK FARTHER AWAY THAN THEY DO WHEN YOU FEEL GREAT.

This pain bias might not be minor. Experiments by Witt's team with patients and staff at a pain management clinic found that distance down a hallway may look up to 30 percent farther to people with chronic pain than to people who are pain-free. This insight could improve the coaching given to people with chronic pain, helping them to cope better.

6. SPIDERS APPEAR TO MOVE FASTER THAN NON-THREATENING OBJECTS.

Science already knew a few things about arachnids and threats. People who fear spiders see them as bigger than the rest of us do, and people tend to see threatening objects as bigger and closer to them than they do non-threatening objects. So in a twist on those findings, experiments by Witt and her colleague Mila Sugovic with images of spiders, ladybugs, and balls moving toward college students showed that the subjects perceived the spiders as moving faster than the other objects. Researchers think the finding shows bias in perceiving the speed of threatening objects, not just insects. But the experimenters didn't ask about arachnophobia, so it's hard to be sure what was going on. The body factor kicked in when the subjects had to try to block the incoming object with a paddle, sort of like a video game. The smaller the paddle, the faster the object seemed to be moving. 

7. LITERALLY ACTING OUT THE PHRASE "THINK OUTSIDE THE BOX" IMPROVES YOUR CREATIVITY AND ABILITY TO SOLVE PUZZLES.

Physical activity of any kind helps get the brain unstuck, but movement that embodies thinking helps us more. It can even work if we merely act out or embody a metaphor for creativity, researchers at Cornell University and Singapore Management University have found. Volunteers in an experiment who sat outside of a big 5-foot-square box placed in a lab as they completed word puzzles performed better on the test than did volunteers who completed the puzzles while sitting inside the box. And subjects in a room with no box at all actually solved fewer puzzles than the subjects who sat in a room with a box but not in it.

8. POWER POSES MAKE YOU ACTUALLY FEEL POWERFUL, WHICH MIGHT NOT BE A GOOD THING.

If you sit in an expansive pose rather than crossing your arms and legs, your brain effectively receives the message that you're in charge of a situation. Such "power poses" could actually increase testosterone levels in our body, as Andy J. Yap, then at MIT, Amy Cuddy of Harvard Business School, and Dana R. Carney of University of California, Berkeley found in two experiments. That sex hormone is linked with all kinds of success states and indicators: feelings of confidence, competitiveness, risk-taking, and improvements in memory and attention. Hold a power pose for one minute and you get about the same testosterone jolt that you feel after winning a game, the team claimed. Dozens of other studies have also shown that embodying power with expansive poses at least increases feelings and thoughts of power even if it doesn't change hormone levels.

9. RIGHTIES TEND TO GIVE HIGHER RATINGS TO OBJECTS ON THE RIGHT SIDE OF A PAGE.

But lefties are just as biased. Our handedness influences our preferences in general. Righties asked to judge products or job applicants located on the right or left side of a page tend to prefer those items on the right, whereas lefties tend in the other direction. Same goes for names on an election ballot. Left-handed voters in a simulated election chose a candidate on the left side of the ballot about 15 percentage points more than did right-handed voters, says Daniel Casasanto of the University of Chicago. Yet another thing to keep in mind in November.

10. WE PREFER TO TYPE PAIRS OF LETTERS THAT ARE EASIER TO STRIKE SEQUENTIALLY ON A KEYBOARD.

That's right: the QWERTY layout of today's computer keyboards influences how we feel about typing certain letter combinations. People who type a lot at computers (let's set aside thumb-typing on smart phones) know that some letter sequences are easier and preferable to punch out than others. Typing two letters sequentially that involve the same finger or are right next to each other can slow down our fingers. So expert typers shown lists of two-letter dyads preferred those that could be typed by two different fingers, Sian Beilock and Lauren Holt found. But we typically like it when a word can be typed all with one hand—for example, "LOL." Hey, we like the easy way out, but it's our body and its interactions with QWERTY that determine what's easy—not simply the mind.  

11. YOU'RE MORE LIKELY TO PICK UP A UTENSIL IF THE HANDLE IS FACING YOU.

Again, we have a bias toward doing things that are easier for the body, but other motor tasks can come into the picture. Volunteers asked to pick up utensils lying on a table tended to pick up those placed so the handles were facing the subjects, Beilock found. That makes sense. But we also tend to pick up an object by its handle even if it's facing away from us. In that way, the object is ready to use. Ever notice how waiters turn their wrists internally to pick up water glasses facing down so they can quickly flip the glass and fill it? Ease of use rules, along with intended use.

12. WHEN YOU HOLD A GUN, YOU'RE MORE LIKELY TO SEE OTHERS AS HOLDING A GUN.

This is where things get serious. In one experiment by Witt and a colleague, university students were given either a gun or a ball to hold and then shown images of a masked man either pointing a gun at the viewer or presenting a shoe to the viewer at the same level. When holding a gun, people were more likely to see a gun and raise their arm to point at the masked man even when confronted with a harmless shoe. In other words, they saw and responded to a threat that wasn't there. A related study by Witt's team involved testing the perceptions of gun owners and video game players holding either a real gun or a toy gun. The video game players were only biased to see a gun if they were holding a real gun whereas gun owners were biased to see a gun even if they were holding just a toy gun.

For more insights into these kinds of fascinating perceptual shifts, tweaks, and changes, check out How the Body Knows Its Mind, by Sian Beilock.