## Things I don’t know how to do, II

When you swipe a card with a magnetic stripe, like a hotel cardkey, or a credit card at a gas pump, there’s typically a little diagram that shows you the orientation in which you’re supposed to orient the card. I cannot read this diagram. Every single time, I have to try each of the two possibilities to see which one successfully swipes. Even while writing this post, I had to think for a minute to convince myself that the number of possibilities which actually send the magnetic stripe through the reader is two and not four. This is why it seems strange to me that people like to use ability to mentally rotate three-dimensional objects as a proxy for math ability in kids. (Of course, there is some evidence for this point of view, which some people might give more weight than my N=1 self-study.)

## 9 thoughts on “Things I don’t know how to do, II”

1. Daniel says:

I have to say that I don’t understand how this is ambiguous. There are four orientations for the card: either the black strip is on the close side of the card, or it is on the far side of the card, and either the black strip is on the right side of the card, or it is on the left side of the card. All the card readers require that the black strip me away from you, so that they can read it, so that reduces the problem to figuring out if the strip should be on the right or left. The symbol on the picture you posted means that the strip should be on the right side of the card, because you can see the strip in the picture is pointed toward the center of the whole reader, which is to the right. Is this clear?

2. Dirty Davey says:

It’s worse when you have a slot where the machine sucks your card in, reads it, and spits it out; in that case there actually are four possibilities. The POS terminal in my local CVS uses an orientation that no one else seems to; I can decipher the symbol but I’d never have thought to try it that way otherwise.

I wonder if handedness plays a role here? If the default image shows the card as held in the right hand, then as a lefty I have to do an extra mental transformation to the hand that actually slides the card. Although the example you show seems to have an illustration set up for a left-hander.

3. JSE says:

The symbol on the picture you posted means that the strip should be on the right side of the card, because you can see the strip in the picture is pointed toward the center of the whole reader, which is to the right. Is this clear?

No! Not to me, anyway. Because you seem to have some mental way of translating that picture into something you can imitate with the card in your hand. Whereas I seem just not to be able to visualize this at all, and in order to get the orientation right would have to set up some elaborate verbal description, and this would take me longer than just trying it both ways.

I have to admit that the particular image included here seems easier to me than the one at the gas station, but that may be because the image includes a picture of the card being inserted correctly.

It may also not be irrelevant that I don’t know what direction “right” is. I only know “left” and when someone says “right” I have to think of it as “the opposite direction from left.”

4. Em says:

I have never given this issue much thought, but it always gives me difficulty. I just assumed I was in way too much of a rush to figure it out.

I did, however, just fill my gas tank by pushing down the little lever just moments ago, so maybe I am teachable.

5. JmSR says:

So, would a label at the top that says “TOP” plus a label on the side that “Black Stripe this side” solve the problem?

Also, many of the new gas station machines allow the card to be inserted either of two way (provided that the top is ast the top).

6. Toby Gee says:

I too have enormous trouble with this, to the extent that it would probably be quicker for me to never think about it but instead just start swiping randomly straight away. The issue reminds me slightly of Langlands’ comments about the left/right side of a page in his review of Hida’s book, which I imagine you’ve seen.

7. Richard says:

Just like Vadim in “Look at the Harlequins!”

8. Zajj says:

This seems like an issue which could easily be solved by a multitude of other learnable means—like, have the reader side be colored black and the other side be colored… something else. Or have a black stripe sticker of the side it goes on… maybe that says “stripe this side”. Or, have two readers, so that it works either way. Or have the non-reading side be thin enough, and maybe shorter or made from a different material, so as to imply that there isn’t anything going on over there. It’s really just a sign of poor product testing, and -very- poor adaptation post release.

9. […] The new paper finds a small but detectable (positive) effect of spatial ability in children on adult measures like patents granted and papers published in STEM.  I hope I didn’t mess up their z-score too badly, because I stink at spatial ability.  I recently revealed to Dr. Mrs. Q., who was horrified, that when we’re inside the house I can’t tell what direction the wall I’m facing corresponds to in the outside world.  Moreover, if I’m on the ground floor, I can’t tell you what’s directly above me on the top floor, or directly below me in the basement.  This is presumably related to my inability to correctly swipe a credit card at the gas pump. […]