Tracking the location of objects in your mind: It depends on what you believe

ResearchBlogging.orgImagine yourself in a room surrounded by eleven objects arranged in a circle. You memorize the position of the objects, then you close your eyes, and rotate a third of the way around (120°). Keeping your eyes closed, can you point to the object that was behind you before? Most people can do this without much difficulty, and only take an instant longer than if they'd stayed in the same position.

Now imagine the objects are rotating on a turntable as you yourself rotate, so that the same object is still in front of you -- in many respects, it's as if you've never turned and the objects never moved. Yet for most people, it actually takes longer to point to the objects than when they had changed position relative to the objects. What's going on here?

It shouldn't be especially surprising that we're quick to remember the location of objects in a room when we have rotated -- after all, this is the kind of thing we must do all the time, like when we look from left to right to decide whether it's safe to cross the road. But there are also times when an object or set of objects move along with us. If you're driving a car and turn around a corner, you still remember that the groceries are right behind you in the trunk. So why is it difficult for us to imagine objects moving along with us?

The first two scenarios I described above correspond to an experiment conducted by Weimin Mou, Xiaoou Li, and Timothy McNamara. They paid students to enter a room configured like this:


Instead of symbols, the room contained real objects, like a candle, a hat, and a ball. Standing in the center of the room, the students first memorized the position of all the objects, then were blindfolded and told to point to the objects one at a time using a joystick (e.g. "point to the candle."). Then they were told to rotate their bodies in place, imagining the objects rotating along with them. Again, still blindfolded, they were tested on the positions of each object. They were also asked to imagine the objects rotating while they remained in place, and to rotate while imagining the objects remained in place. Here are the results:


This graph doesn't actually show you much. To really see what's going on here you need to transform the data. We need to consider two possibilities: First, when the objects were in the same position relative to the viewer as when they were learned, like this:


When the position where the objects was learned is the same as where they are imagined, then the learned position minus the imagined position equals zero, like in the first data point on the graph. The second data point on the graph shows how long it took viewers to point to objects when they had rotated, and also imagined the objects rotating. So from the perspective of the viewer, the position of the objects didn't change, yet it took nearly twice as long to point to the objects.

Now consider when the position of the viewer relative to the objects did change:


A second line is added to the graph. The original, blue line, represents when the actual position of the objects minus the imagined position of the objects equals zero -- when the position of the objects relative to the viewer didn't change. The new, green line, represents when the position of the objects relative to the viewer did change. The first point on the green line shows what happens when the viewer rotates but imagines the objects staying in the same place. The second point shows what happens when the viewer stays in the same place but imagines the objects rotating.

Next the researchers demonstrated to a new set of students that the objects were actually on a turntable that could rotate, while the viewers themselves were on an immobile platform in the center. In the first experiment, viewers hadn't realized that the platform was able to rotate. Now the experiment was repeated in an identical fashion, except that while the viewers were imagining the objects rotating, the experimenter actually rotated the platform with the objects, so the objects actually moved just as much as the viewers. The viewers were told in advance this was what was happening, but from what they could actually perceive during the experiment, it was identical to the first experiment -- remember, they were blindfolded the entire time.

This time, the results were decidedly different:


The two lines now overlap nearly exactly. Whether the objects were shifted relative to the viewer or in the same position relative to the viewer, it took the same amount of time to point to the objects. Simply knowing that the platform supporting the objects could turn drastically affected the results.

So it seems that there are indeed times when it's just as easy to imagine an object moving along with us as it is to imagine it staying in the same place as we ourselves moves. Previously, many researchers had assumed that we are simply better at imagining objects staying in the same place, but this study demonstrates that when we truly believe an object is moving along with us, we can track it in our minds just as easily as if it was standing still.

Weimin Mou, Xiaoou Li, Timothy P. McNamara (2008). Body- and environmental-stabilized processing of spatial knowledge. Journal of Experimental Psychology: Learning, Memory, and Cognition, 34 (2), 415-421 DOI: 10.1037/0278-7393.34.2.415

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Hmmm. OK, how about this scenario: I'm riding on a carousel at the State Fair with my kids. Before the ride begins, I identify a blue horse opposite my location on the carousel. I also mark the location of my wife who is standing on the ground next to the carousel. The spinning begins. So, this study says it would be just as easy to point to the blue horse during the ride (moving with me) as is it would be to point to my wife on the ground (not moving with me)? Just imagining this, I would guess it would take longer to point at my wife than the blue horse because the horse is in a fixed position and my wife is in relative constant motion. Does that make sense or am I comparing apples and oranges?

this is all about relativity. Its the same scenario played out over and over again, everything is relative to space and time, which is actually called, spacetime. To directly comment on your question, I would have to know your relative question. Because, you say "moving with me/not moving with you" then you are comparing this relative to your motion. In the theory of relativity, youre moving and you are not moving at the same time depending on your relative motion to something else. Then if you really want to feel small and blow your mind and make the question completely irrelevant in the first place, you could think about how we are all moving at a constant rate relative to different things.

It would happen in this order of thought; 1. You are moving at a rate that seems to be faster than your wife on the ground, but, 2. Your wife isnt really standing still, relative to the ground or some other seemingly "stationary" object, she is actually moving with the speed of the earth (and so are you +/- the speed of the carousel) now.. 3. which speed of the earth am i referring to? the speed in which it turns? the speed in which it moves around our sun? the speed in which our earth moves around our sun which moves through our galaxy? or the speed of the galaxy moving through space? These may seem like minor questions until you start looking at some of the approximate math. See, the earth rotates (at the equator) at about 1000mph. stop... breathe... ok 1000mph is how fast your wife is moving around the center of the earth if you are on the equator line and she is standing on "stationary" ground. Oh but... then think about how fast the earth is moving around the sun? oh yeh, i mean, we dont go around but once every 365 days, so its not that fast right? try 29.6km/s (around 66,200mph). So how fast is your wife moving? dammit, what about the solar system? the earth rotates around the solar system, and the solar system isnt stationary, 483,000mph.... ? so .. how.. fast are you.. really moving? oh god. now what about the galaxy? the milky way? a galaxy in the suburbs of the galaxy-world, 600km/s. SIX HUNDRED kilometers a second, 1.34 MILLION miles per hour. So... your going around a carousel and your wife is standing still. lol, kind of humbling is it not?

My head is spinning, our son switched horses, and my wife took our other son to the Tilt-A-Whirl. Now, about that Tilt-A-Whirl ride, if I sit on the inside of the car closest to the edge and....... never mind.


It's a pity they never tried this on Einstein!

This study seems similar to the mental rotation/focal dystonia study that showed a relationship between movement and mental imagery. The difference between them however, is that while the dystonia study demonstrated how a movement impairment negatively impacts movement imagery, the current study demonstrates how movement helps movement imagery.

It would be interesting to see what the data looks like for persons with focal dystonia.

By Tony Jeremiah (not verified) on 16 Jul 2008 #permalink

"this is all about relativity."

No it's not. It's about cognitive processes affecting perception.

Regarding your carousel scenarion, I see two essential differences with the experiment:
- the persons in the experiment make the turn themselves whereas the carousel turns you around. Try the experiment: close your eyes and make the turn; you would be able to locate the immoble things around you.
- the carousel would spin in a continuous motion, whereas the experiment is a single turn over 120 degrees. If the carousel would stop after 120 degrees, you might still be able to point at your wife. Extend the previous experiment: close your eyes and spin at least ten times around before you stop. You probably will have lost track of anything...

"Previously, many researchers had assumed that we are simply better at imagining objects staying in the same place, but this study demonstrates that when we truly believe an object is moving along with us, we can track it in our minds just as easily as if it was standing still."

This seems like the wrong conclusion to draw. In the final graph, the left two dots represent the cases where the objects did not move. They are identical, and both lower than the two (also identical) dots on the right, showing the cases where the objects did actually move.

In other words, it IS true that the subjects were better at tracking objects that did not move than those that did. What did NOT matter -- and only in the case where the subjects believed the objects truly could move -- was whether the subject moved WITH them or not.

Just speaking for myself, I know I have a difficult time actually picturing things spatially. Like, it is difficult to imagine the relationship over time of the moon and the earth, for me. It just is too big. I picture the earth, and then I picture the moon, and I can imagine a still image of them in relation to each other, but as soon as I try to start imagining them moving, it all gets blurry and my brain starts to hurt. Dunno if that is related, but I bet a lot of people have this kind of spatial difficulty.