Great animation: why we can't walk straight

NPR's always interesting Robert Krulwich posted a great report on why people can't walk in a straight line from point A to point B without visual cues. Usually gimlets are involved in my case, but even sober, it's likely you will end up going in ever-tighter loops. Benjamin Arthur's beautiful animation alone is worth checking out. Important viewing if you're searching for the Blair Witch or planning to walk to the neighbor's during a blinding blizzard. Video link.

A Mystery: Why Can't We Walk Straight?

Andrea James is a writer, director, producer and activist based in Los Angeles. Her work often focuses on consumer activism, the free culture movement, exogenous mysticism, humor, and LGBT rights.

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Anonymous

In my view the reason why we can’t walk straight without using our sight is the same reason why “dead reckoning” is such a challenging problem in robot and UAV navigation. After all, without sight what we do is pretty much dead reckoning anyway!

For those who don’t know, dead reckoning is the process of obtaining an object’s path given only its starting position and some motion measurements, such as the object’s velocity vector at each time instant, or its acceleration, or the direction of motion plus the number of steps the object took (for example number of turns of a wheel, or number of actual steps taken by an animal).

The issue here is that in any of these cases your brain (or the robot or UAV’s CPU) has to integrate (in the Calculus sense) the information from multiple time instants, which makes small sensing errors accumulate into ever larger errors. So the longer you walk for, the larger the error, until you get entirely lost.

Nowadays, what many robots and UAVs do is to employ *an additional* sensor that, every now and then, gives a better location estimate that allows them to correct the course. This usually means adding a camera to the system — which is precisely what we ourselves do when we remove the blindfold :)

Wiki page on dead reckoning: http://en.wikipedia.org/wiki/Dead_reckoning
Anonymous

Heh, it turns out that what I said is pretty much what Anon (post #21) said. It just seems to me like the obvious answer… so I’m glad I’m not alone :)
Anonymous

Worth remembering that they walked in circles and didnt just meander and also that they had the intent of walking in straight lines. Small point I know but animals have no concept of straight lines.
I like the concepts posted of a bell ringing serving as a directional cue or even a smell. Touch and taste would require contact to guide us but still viable.
How about the heat of the sun on our face.
Or the north wind blowing at us.
mcnorthernal

This was interesting, but whats more interesting is how we can walk home unconsciously drunk. Has there ever been a study of this phenomenon? I done it myself and I have witnessed drunk people stagger down a street dangerously swaying towards and away from the road and other pedestrians
- jackie31337
  
  whats more interesting is how we can walk home unconsciously drunk
  
  I would argue that you and your fellow drunks are not actually unconscious, just not storing memories of your actions. I’ve often found myself at work in the morning with no explicit memory of the steps I went through to get there. I think it’s largely the fact that the actions are so routine that I can do them automatically without consciously thinking about them.
Anonymous

very interesting info and examples. fantastic animation and sound effects as well
kittnkat

we are made up of never ending fractal spirals from tiniest to largest in every breadth weight dimension relation, of course we’re just unconcious spiral making machines….duh.

Ps Gorgeous animation, thank u.
Anonymous

Maybe…because the earth is moving too?
Anonymous

It is the rhythm of our breathing that causes us to drift away from a straight line. As our diaphragms tighten they apply a slight torque on our spinal columns, which results in a drift to the right or left. As our breathing rate increases, so does the drift.

To test my theory, go for a walk blind-folded while holding your breath. You will be amazed at how far you can go in a perfectly straight line.
Anonymous

http://www.gutenberg.org/files/10245/10245-m/10245-m-001.mp3
DrPretto

Excuse my mistake, my reply was for #25 (amuderick) not mdh.
lakata

My point was not that the right-leg was longer or shorter or heavier or anything. My point was that any small asymmetry in the body that results in a trivial but constant error *will* result in going in a circle. If the asymmetry happens because one side gets tired faster than the other, then the radius of curvature will decrease as the asymmetry increases. This explains the swimmer going into a spiral. I didn’t notice the walkers go into a diminishing spiral; their circles got bigger *and* smaller.

Have you ever driven your car on a straight bit of freeway and let go of the steering wheel? How long do you stay in your lane before you grab the steering wheel? Maybe 5-10 seconds? Even if your car is very well aligned, a 10 foot error after 1000 feet of driving is only a half degree of error. But half a degree times 720 is a full circle. Your car will go in circles too, and this is a machine whose geometry that is much more precise than that of the human body.

My point is that the only way to go in a straight line is to have identically zero heading error (impossible in the real world) *or* some closed-loop feedback to correct (unlikely being blindfolded). In other words, going in a straight line is the exception, and curves paths the norm.
Galoot

Has anyone tried this experiment on a perfectly flat plane (impossible)?

My theory is that there are no straight lines in our imperfect world, at least not for the definition of “straight” that we all seem to be working with here.

Also, chaos theory suggests that it’s well nigh impossible for a car driver to start out with his wheels perfectly aligned.
Anonymous

Lovely animation – excellent illustration of the conundrum – thank you :)
Anonymous

I thought there would be a solution! I want my money back!
johnnyaction

I used to live where it snows heavy and hard and we always had a rope in the car if we got stuck in a blizzard. The rope wasn’t to get the car unstuck but just to tie to the door so you could find the car if you had to leave the car to go back to the trunk. Sounds crazy but people die in blizzards getting lost right near their car.
SlashMatrix

Asa Schaeffer was either a really trustworthy chap, or he had some seriously gullible friends. “I’m going to blindfold you and take you out into a field for science!”
Anonymous

I think most of us had the same thought after watching that.. “Well, I could walk in a straight line..”
Anonymous

That’s really beautiful animation over a really interesting topic. Awesome.
Anonymous

I tried walking BACKWARDS in a straight line and fell into a lake, did the backstroke and swam directly to the opposite shoreline, got in my car and drove straight home.
Anonymous

It seems to me that the most reasonable explanation is bc of the Earth’s rotation.
supnah

My money is on something behavioral. Think about young children or babies who are left unattended momentarily and begin to wander off. Higher survival rate for those who, even when intending to go straight, end up curving back in circles toward the camp, village, cave, etc. And then maybe that is just never lost because we’re so dependent on our sight and visual cues to know where we are that there’s no strong evolutionary pressure to overcome that tendency developed for safety during youth.

I guess the thing to ask about this is whether babies use visual cues when they wander off… anyone seen any published articles about that?
lakata

I don’t get it. I don’t understand why this is interesting. If you have a left foot and a right foot and they are not exactly equal (which would be impossible unless you constructed each to the atomic level), then one will move slight faster or farther or twisted compared to the other foot. Any slight imbalance will make you go in a circle. Consider the following exmaple, were for every pace you make forward (say 5 feet), you make a 1 inch error to the right because your legs are not perfectly symmetrical. 1 inch over a pace is not a whole lot of error. The arctangent of 1 inch over 5 feet is about 1 degree. That means after 360 paces, you will have made a complete circle by turning 360 degrees. 360 paces is not very far (would only take about 6 minutes of time, about 1/3 mile).

So why is this interesting?
- mathdemon
  
  This would mean that most people would have a shorter right leg as it seems that the majority of the paths taken are clockwise. Would you also be confident to claim that we would steer toward one side because our arms aren’t symmetrical?
  
  In your claim, one would also assume that the rest of the body was symmetrical in mass, and that you had a static equilibrium point. And that the ground they were walking on was flat. So it’s a pretty weak claim.
  
  How would you respond to someone who would claim that because we didn’t have perfectly symmetrical body in relation to mass, and that one side of our body had more mass then the other, and therefore this would affect our choice of motion. I guess right hand dominance would mean more muscle mass in your right arm, and you’d probably also be right leg dominant, therefore more mass in your right leg. It’s often encouraged that you sleep on your right side to avoid having your heavy organs on your right side to push down on your lung, and mess up your spine, etc, so we could assume that one’s right side had more mass. So this would have us to lean more toward our right, and thus move in a clockwise motion if we were blindfolded. Is this a good claim? I don’t think so.
Donald Petersen

A Mystery: Why Can’t We Walk Straight?

I was a Theatre Arts major in college, and a couple of classmates and I were driving to meet friends at a bar after rehearsal one night. Addam was driving and wasn’t sure which was the best way to go. I instructed him to turn right on Fletcher Parkway and then go straight. Laurel piped up from the back seat, “Never straight! Gaily forward!”

Okay, maybe you had to be there.
Anonymous

This happens to me every time I go out to catch a Woozle in the woods.
- Nantsy
  
  Damn you, elusive Woozle!
schmittenhammer

I remember (somewhat, too long ago) math class the example of the ‘random walk’ a squiggly line to represent a totally random function. Yes that is even sober our path is random……..
pidg

Sorry, what’s the connection to Jared Lee Loughner?
LandanJ

If you were to find the answer, or try to, I think the increase in correction over time would be an important clue. Also I think it destroys the argument that I have seen above for asymmetry. If it were due to asymmetry or a physical tendency of any kind to one side then the arc would remain constant or nearly so.
The first test I would want to do is to blindfold the subject for a period before he/she walks to see if prolonged deprivation has some correlation to the amount of correction. I would hope to see shorter sharper arcs from the very beginning.
I could see an evolutionary basis for this. If a person is wounded, lost in a storm, fog ,etc it would be much more likely for them to reunite with the group if they were to walk in this way rather than if they dash off in a random strait line. If they walk in a strait line there is a chance that they will go very far in the wrong direction and die.
Anonymous

There’s something missing here: Can blind people walk in a straight line?
I’m inclined to think it’s just that without our usual feedback, our self-correction runs away with itself, misinterpreting other tiny forms of perceived feedback.
- Anonymous
  
  Whoaa can they?
- Anonymous
  
  They use a stick or use hearing to “see” Where they’re going.
- desprez
  
  I’m guessing it’s not just a visual thing. I would think you would have to control for other directional sensory cues. For instance, I see no reason something like a bell ringing in the distance couldn’t substitute for a tall landmark to keep someone on course.
  
  With that said, it would be interesting to see how different sensory cues effect this behavior. But I suspect that anything that can be used to determine direction, could be used to keep you walking straight. While something that is omnidirectional but based on signal strength, like a smell perhaps, may not prevent a winding path but could still get us to the destination eventually.
  - Andrea James
    
    @desprez: I know there’s a similar spatial disorientation issue with flying airplanes in conditions where the sun and horizon are hard to see. People can fly in circles and also can have no idea whether they are climbing or descending.
    
    http://en.wikipedia.org/wiki/Sensory_illusions_in_aviation
    http://en.wikipedia.org/wiki/Graveyard_spiral
    - jackie31337
      
      I’ve always wondered how someone could get disoriented to the point that they don’t know up from down. I like to think that it couldn’t happen to me (I have very pressure-sensitive ears) but I have no direct experience. I would be very interested to see what would happen.
- Anonymous
  
  well blind people are constantly trying to get feedback from other sources than sight such as banging on stuff with a cane or holding on to a dog but that would be a good test
mathdemon

An interesting observation (just an observation, not a proven theory) is that people who escape from prisons tend to often yield to the right. Same observation is done for people who commit robbery and take a right turn immediately after they exit the doors. Law enforcement (and military dog handlers, etc) who chase people on the run are often instructed to favor searches “toward the right.” This comes from my own experience as a service member in a country that had compulsory military service. I have not been able to find civilian literature that could support these claims. But they’re tested, and this technique tends to work to locate somebody even long after LE/military arrives to the scene of the escape. It’s much more effective in rural areas than urban of course. Dog handlers will also be vary if the tracks follow a left hooked path. They usually slow down as this could indicate an ambush attempt. Once again, I don’t know if these are techniques known to other military organizations, such as the U.S.

The video mentions right-hand dominance… I realized that I would probably veer toward the right if I tried to avoid an obstacle on the road, and I’m right-hand dominant. If a motorcyclist had to do a turn from a standing position, they’d probably start off with a left-turn (I’m right hand dominant, and I’d do this). I also think that the “correct” feeling of right-circular (“clockwise”) orientation of clocks/watches can’t be a coincidence. I’m just pulling these out of my ass, but I think this is a good starting point for a flame war. :)

Oh, and car chases off the highway. The drivers TEND to make more right-turns than left when they’re driving on streets.
- Anonymous
  
  “Oh, and car chases off the highway. The drivers TEND to make more right-turns than left when they’re driving on streets.”
  
  That depend on what country they were driving in? i.e. if they wer ein the UK or the US, as they drive on different sides of the roads and sit in different sides of the cars (affecting visibility etc.)?
  
  I wonder how these cultural aspects affect the effect.
  
  Interestimng info though … I only hope it’s true cause I’m bound to spread it …
Anonymous

can this be trained out or corrected.
- Anonymous
  
  Yup.
  
  Pilots learn to ‘fly by the seat of their pants’. Which is all about using factors other than sight to navigate and orientate.
  
  That does however still require some stimulus.
- Anonymous
  
  can this be trained out or corrected.
  
  Yes, martial artists sometimes practice blind walking as a way to develop proprioception and integrate it with internal vestibular balance. They also do blind exercising on one foot; hopping and moving between various strenuous and relaxed poses.
  
  An expert practitioner in good health should be able to walk a perfectly straight line on a perfectly level, smooth floor without a problem. It’s also possible to walk a very straight line across unknown, broken ground – but only when exercising total concentration (which rules out doing anything other than walking, and you need bare feet so the ground can’t be too actively hostile).
  
  My teacher could do a dozen or more complex katas blindfolded, and return to within an inch or so from where he’d started after each one. After 40 years of practice he knew how far he’d moved, and in which direction, without conscious effort.
radam

does anyone know what the jazz song is at the end of the video?
- Anonymous
  
  Hey Radam, the music at the end is Alligator Crawl by Louis Armstrong. [s]
- Anonymous
  
  Louis Armstrong [ffrom the '20s]
  - “West End ?? Blues”
- Anonymous
  
  Alligator Crawl, Louis Armstrong
  - radam
    
    thank you! i thought it was louie
Anonymous

SamSam #62 makes a good point. Several posters say that it’s not surprising that people can’t maintain a straight line, but what’s interesting is the ever-tightening spiral effect. SamSam’s idea that people are overcompensating for the suspicion they are veering off course makes sense in helping to explain this.
bhtooefr

Here’s something that would be interesting to see:

Run the experiments in the US, logging the direction of spiral.

Run the same experiments in the UK and Japan, and compare the [b]direction[/b] of spirals. I noticed most of the spirals in that video were to the right.

Run the same experiments in Australia, and compare the direction as well.

Why the UK and Japan? They drive on the left, their innate correction may be programmed differently.

Why Australia? They also drive on the left, but being in the southern hemisphere, it could make things interesting.
- EggyToast
  
  They tried the experiment in Australia, but after the first three subjects who wandered around blindfolded were killed by a highly poisonous snake, a highly poisonous spider, and an angry cassowary, they decided to stick to less dangerous geographic areas.
Strange Quark Star

My geography teacher in high school explained this with the Coriolis effect.
- Anonymous
  
  The jazz song at the end is Alligator crawl by Louis Armstrong from the album The Hot Fives And Hot Sevens – Volume II
gwailo_joe

Why??? Who cares why: all those things the guy said at the end. . .or whatever.

Humans: not as unique as we think we are.

‘To sheep other sheep no doubt appear different. . .Or to shepherds.’

Still: this lil’ film was educational and awesome. . .yay BB!

(I came for the divisive political discourse; but I stayed for the creative historical animations. . .)
snej

@pidg: It’s a pretty clear metaphor. The scientist is Sarah Palin, the blindfold is right-wing rhetoric, which causes Jared Lee Loughner’s mental processes (represented by the walk) to deviate increasingly toward twisted violence.

Either that or the blindfolded guy is BoingBoing and the scientist is the left-wing Mainstream Media…
Anonymous

A straight path is only one, compared to the infinite non-straight paths. It’s very much more probable to walk away from the straight line when none of our senses can give us a clue of where we’re going, rather than being able to stick to it.
It’s enough a little asimmetry in our legs, or in our sense of equilibrium or whatever else, and we’ll drift on one side more than in the other one, resulting in a circle walk.
Anonymous

“left-wing Mainstream Media…”

LOL
obdan

We used to hunt rabbits back when I was a kid. (sorry about that). They would always tear off running when you spooked them, and they would always run a big loop right back. You just had to kind stand and wait for them.
- Anonymous
  
  yes, but all rabbits are mildly suicidal.
Anonymous

Look up “servo” in wikipedia.

Walking in a straight line is a classic example of a feedback loop. So are driving and swimming. You are constantly correcting for tiny deviations from your intended path. These corrections are small, so you probably hardly ever notice them. Take away the feedback (vision) and you have nothing but a wobbly system that goes where it will. Add even a slight handedness (which everyone has) and you get circles.

At least, that’s what I think!
Anonymous

Mr. servo here:

Forgot to mention that Radiolab is so awesome it makes me a little giddy when I think about it. Now they do cartoons with fancy moustaches?! Amazing!
Scixual

Guy looks a bit like Jack Black.
Matthew Walton

This makes me think of an aikido class I once did where the instructor got us to run through kihon dosa (a series of movements fundamental to the style) with our eyes shut. It was incredibly difficult – without visual references, it’s difficult even to stay upright through the various steps and slides and pivots, let alone get the angles of things right. Apparently it’s possible to learn to do them all properly without eyes, but personally I think I’d want a bigger room. I even started to get paranoid about hitting the ceiling, which seemed to me to be getting lower with every step.

Thus I can well believe I can’t walk in a straight line with my eyes shut. I’d like to see a study of this nature on people blind from birth – do they learn how to do it without a stick?
Anonymous

What I don’t get is why anybody thinks a person, blindfolded, *would* be able to walk in a straight line without external reference? No machine moves in a straight line without external reference and I can’t imagine how you’d build a machine to do it, except by making it as symmetrical as possible.

Is the surprise just how bad we are at it? Or that we tend to one particular direction? That the direction we tend towards doesn’t relate to anything obvious — terrain, physiology, handedness?

The animation is lovely but it’s missing the interesting part of the question.
Anonymous

Indeed a question is if blind people can walk straight (without holding a stick or having any haptic cues from the floor [e.g. a blindfolded acrobat can walk on a wire cause the wire is the queue, although without opening their hands or holding a stick horizontally to balance, not sure if it would be easy for them])

I like the Roboticist approach – my first reaction to the spiral patterns in the video getting smaller and smaller was that it has somehow to be related to the balance organ in our ears that’s also spiral :-)
pidg

Surely the car one would be easy? Just don’t turn left or right.
Anonymous

Speaking of the brain, a really interesting thing I was surprised to be told about recently by my father-in-law (a neurologist & psychiatrist) is that you can’t rotate your hands to one direction while rotating your feet to the other direction. Just try it!

Interestingly, you can rotate say both hands and feet inwards or outwards (left&right hand do reverse direction that is), but the feet have to do the same on the left and same on the right as the respective hands (that is either inwards them too or outwards, not the other way or both left/right when the hands to other thing)
Michael Slater

Oh this sucked…

The cartoon and narrator was nearly as annoying as Robert Downey Jr. in Scanner Darkly.

Plus there was no answer at the end. Lame.
SamSam

All those who are saying that this is just due to a slight asymmetrically in our bodies, or that it’s just a one-inch error being compounded over time, are ignoring the part of the video that claims that people keep walking in ever tighter circles — that they end up walking in a spiral.

What would be the cause of this not-only increased error over time but accelerated error over time?

My hunch: somehow, even though the participants were veering to the right, they felt like they were veering to the left. So they continuously tried to correct themselves. The more they veered to the right, the more they tried to correct themselves, and ended up compounding the problem.
Buckets McGaughey

I’ve actually done this, sort of. It was as part of an assessment by a personal trainer-cum-physio. He suspected that I had a misaligned pelvis, with the result that one of my legs hangs slightly lower than the other and throwing me just a bit off balance. He said it’s not something you normally notice because you correct for it through vision, but when you can’t see, your body’s inherent imperfections send you out of whack.

To prove the point, he stood me against the wall in a room and told me to walk on the spot with my eyes closed. Whilst I was doing this, I wondered why he kept moving around whilst talking to me throughout, but when I opened my eyes I realised why – he was trying to stop me realising what was going on. I’d moved across the room, forward and quite a way to the right. I was amazed, I’d no idea. The forward part I could understand, but hooking to the right was a result of me being lopsided. I didn’t have to move more than a couple of metres to show it, either.
jimkirk

While it’s interesting that there’s no consensus for a cause, it’s not surprising that we can’t, any slight offset or imbalance at all will prevent a straight line.

Curious that in some examples (the foggy walk) the radius of curvature is fairly constant, while the swimmer makes tighter and tighter curves; whatever imbalance there was seems to have gotten worse as muscles got tired.
asbuuu

Why can’t we walk in a straight line? Because it’s hard. It’s very hard. I think the opposite question is more to the point: How in the world could we ever walk in a straight line without some frame of reference? Even a well paved road has a grade to it that will slowly push one off to the side. Think about a wooded environment where every step is unpredictable. Being able to integrate all that information from our sense of touch and balance alone is just too hard a problem, for us, or the best robots. I think that its common now to assume that the environment we live in is more predictable and controllable than it it ever was, or still is today.

All that said, RadioLab is still the best thing to happen to the radio since, well, ever:-)
Anonymous

Coriolis effect. Earth’s roation. Inner ear funtions.
Anonymous

I was surprised that neither the linked article, nor the animation, nor the journal paper by Jan Souman suggest what seems to me as a very obvious potential explanation. I come at this from a background in biologically inspired robotics. Mobile robots operating indoors (i.e., GPS-denied) with only an IMU (inertial measurement unit) often exhibit very similar behavior (this might be useful for a Roomba!).

The human vestibular system (the inner ear) is an acceleration-based sensor. Therefore it can only be used to sense changes in position indirectly through integration over time. These integrations (acceleration to velocity, velocity to position) lead to the build-up of error over time, unless intermittently corrected for by some other fixed reference-frame-based sensor. This is widely known as inertial integration drift:

http://en.wikipedia.org/wiki/Inertial_navigation_system#Error

The visual system, which is tightly coupled with the vestibular system (e.g., vestibulo-ocular reflex), could “zero” out the error in the position measurement. A fixed landmark (or even one that moves slowly relative to us, like the Sun) can act something like a GPS satellite that intermittently beams a correction to correct our continuous estimate of where “straight ahead” is. However, when the individual is blindfolded or in an environment with no clear global landmarks, noise is introduced and not properly cancelled out. In a blindfolded human, the neurons that normally receive the visual position input would be left with only their own internal noise and minor input from other areas. In the case where the individual isn’t blindfolded, but there are not global landmarks (e.g., Sun or a mountain), noise could be introduced by the person constantly fixating on different spots that they think are straight ahead. This would cause the error to be improperly zeroed.

N.B. All of the above is speculation. The integration between the visual and vestibular systems is complex. It is likely that other sensory systems, such as proprioception, are involved at least in some way. It would be interesting to gather statistics on walkers in a virtual reality arena and even inject noise into their visual field to try to tease out how it may or may not get integrated into their resultant path.
Anonymous

They got this issue clear on TV a while back, some pseudo scientific show.

It is due to weight. Most people are better trained on the right side therefore heavier and therefore lean to this direction.

You can cancel the effect by putting a counter weight on the opposing side and voila you can walk straight lines even blindly.
Peter

You’re all overcomplicating it. Why can’t we walk in a straight line?

Because the Earth is round!
Anonymous

Good try guys. I’m surprised no one hit the answer.

One of your legs is stronger than the other. This leg, usually the right, preferentially holds your body weight while the other leg, usually the left, feels out for the next step. Then the weaker leg takes the weight and the stronger leg quickly finds it’s step. Thus, often injuries are to the stronger leg and foot. Since most people are right dominant, their left side of path travels further than their right, making their trail veer to the right. Mathdemon hit on some of this in his/her first post.

Try it yourself, even without a blindfold. Which leg is more comfortable holding all your weight? Which leg prefers to travel a longer distance? When you quiet down and listen, your body has the answer.

-Emily
JayConverse

@ Radam –

I can’t place the song, but since it has a tuba, it’s probably an early Louis Armstrong, the Hot Seven, circa 1928.
tylerkaraszewski

The title of the post implies the video will give us some explanation. Alas, I am left disappointed.
- Andrea James
  
  @tylerkaraszewski: The post gives a precise scientific explanation. It’s because we are trying it blindfolded.
  - tylerkaraszewski
    
    Ah, of course! I must have missed that part.
amuderick

To make this interesting, I think you first need to prove that a large majority of other animals CAN stay straight and that humans are the exception.

Many birds and possibly other animals can use the Earth’s magnetic field for navigation…so they can do this blindfolded and we know why. But other animals?

I agree with Anon #12. Our vestibular system isn’t capable of picking up these subtle shifts in direction amongst all the other noise (up, down, walking, vibration of moving, etc). Without other sensory clues to correct us, we meander.

If you monitor people’s driving in slo-motion, I suspect you will see this behavior….drive, veer off, correct, repeat. It only appears ‘straight’ because of your rough measurement and timescale.

I do recall that in fiction and non-fiction people who are lost often end up where they started. As an avid hiker (often off-trail) it takes a lot of training and diligence to stay on course without a compass on a completely overcast day. All sorts of ‘optical illusions’ in the environment will throw off your judgement.

Perhaps there is a benefit to the end result…if you have no clue how to escape a place, maybe you are better off ending where you started…a semi-safe launching point?
- Headbone
  
  “Many birds and possibly other animals can use the Earth’s magnetic field for navigation…so they can do this blindfolded and we know why. But other animals?”
  
  hmmm, citation requested please. Are you saying that birds can successfully migrate when blindfolded? Or the dog (or cat) that found his way home more than 20 (or 200) miles could have done it blindfolded?
  
  I agree that animal navigation is amazing to us, and may very well indeed be based on the earth’s magnetic field, but I very much doubt your actual claim here, sir.
  - Anonymous
    
    http://www.backyardnature.net/birdnavi.htm
    
    that is a good starting point. You can delve deeper by following the references
    - Headbone
      
      “even if the birds were blindfolded during their trip and you took them hundreds of miles away in a randomly chosen direction, they’d probably find their ways back to their home cages. ”
      
      Probably? Still not good enough. How can a bird not smash into stuff when it’s blindfolded?
Anonymous

oddly explains why i miss most of my straight shots at pool but pot the most ridiculously angled ones lol nice one
PFlint

One leg is shorter than the other.

K, I don’t know this for a fact, but hey, they’re the investigators. They should investigate this possibility.

[Disclosure: I did not RTFA. Because, whatever.]
- Antinous / Moderator
  
  I have rotatory scoliosis, a chronically torqued pelvis and one leg (functionally) longer than the other, and I’m quite good at walking a straight line blindfolded. It’s really about awareness of subtle clues.
  - Brainspore
    
    It’s really about awareness of subtle clues.
    
    If you use clues (like a sound or a breeze) to help guide your direction then it’s really beside the point of this experiment. I don’t think anyone is trying to imply that blind people are completely incapable of finding their way around.
mdh

i’ve always found this anecdote to be very interesting: http://www.straightdope.com/columns/read/659/why-do-so-many-native-americans-work-on-skyscrapers
- DrPretto
  
  “Perhaps there is a benefit to the end result…if you have no clue how to escape a place, maybe you are better off ending where you started…a semi-safe launching point?”
  
  I completely agree with you, and thinking in the same line, I would add that maybe there is an evolutive adaptation kind of explanation for this, maybe our human brain is programmed (instinctively) to no matter how much we walk, we would always end near our start point.
  Imagine cavemen: They hunted or collected food, then they returned to their homes (caves?) to feed their children, if this adaptation didn’t helped them, maybe they could get lost, never find their way home, and finally extinct as species (remember human babies depend 100% of their parents for safety and food), I know this explanation is a little extreme, but I think the answer is in our brains, not our vestibular-cochlear system.
  - SamSam
    
    That’s an unnecessary evolutionary explanation. My cat knows her way around the neighborhood. She recognizes the houses and the yards and the streets. If she got dumped in a nearby yard, she’d recognize the landmarks and be back home by dinner.
    
    If my cat can do it, so can a caveman.
    
    There’s no need for evolution to bless us with something that causes us to walk in circles without our realizing it when practically any animal with a spinal column is perfectly capable of making mental maps of their location and surroundings.
    - DrPretto
      
      It’s your cat blindfolded like the experiment?
      People in the experiment were blindfolded, to discard the influence of reference points, maybe in a big forest your marks are not always easy to find, oh and your CAT is ANOTHER SPECIES and if you read what I wrote, I never said mine is the best explanation, I used the words “MAYBE”, and “A LITTLE EXTREME”. Mine is just a quickly thought Hypothesis, maybe yours (that I do not see written here) is better.
  - Nantsy
    
    That’s a very interesting explanation, but I’m worried about the poor lost caveman who THINKS he’s walking straight back home, but circles back to his original (lost) location.
maxoid

can people be trained to improve their sraight-line ability, though? would training in one mode (walking, say) translate to another (swimming)?

also, i love simple questions that just turn into more questions, rather than leading to simple answers. that’s how you know you’ve found something interesting!