Jonathan Dobres

I became a published author as of a few weeks ago! The paper is titled “Perceptual learning of oriented gratings as revealed by classification images”, which is…a mouthful. Don’t get me wrong, I’m very proud of this. Designing the experiment, collecting the data, and writing the paper all added up to a tremendous learning experience, and the final product is a solid piece of work. Still, it’s not exactly beach reading. So, herein and forthwith, a plain-English explanation of this thing I just published. Yes, you too can understand science!

Before you can really understand what this paper is about, you need to understand perceptual learning. I’ve talked about this before, but here’s another quick primer. Learning of any sort requires practice, whether the goal is to recite all 50 state capitals from memory, ride a unicycle, or perhaps most interestingly, do both at once. In these examples, learning involves the parts of your brain that handle memory, motor skills, or both. Likewise, practice can also change the parts of your brain responsible for vision. When you perform a difficult visual task again and again (like, say, a dentist looking for cavities or a hunter looking for deer), the neurons responsible for processing this visual information become more refined, better at representing the important aspects of the task. It’s not that you simply understand what you’re looking at in a different way (which would be a change in strategy), it’s that you are literally getting better at seeing. Perceptual learning can enable a person to detect tiny changes in an object’s position, make a person more sensitive to detecting motion, enhance contrast sensitivity, and many other things.

So how do we measure perceptual learning? Typically we’ll sit you down in a dark, quiet room and give you a difficult visual task to do. At first you probably won’t be very good, and your answers will be random. But after making thousands of these visual decisions over several days, you will get better at it, and we’ll be able to measure that improvement. Usually we’ll boil all these trials down to a simple summary, like percent correct. The point is that we’ll sit you down for an hour at a time and have you complete 1,000 trials of an experiment, and out of all that data we’ll extract perhaps a handful of useful numbers.

This very common approach comes with some limitations. First, it seems a bit wasteful to sit someone down for a full hour and have only a few useful numbers to show for it. More importantly, though, remember that I’m using your behavior (how well you do on the task) to draw conclusions about what’s going on in your brain. This is problematic, because while I can see that you’re learning the task, I can’t say what, exactly, is being learned. This is one of the major debates in the field. Are you getting better at the task because your brain is becoming more sensitive to the important parts of the task, or because your brain is getting better at filtering out the parts that don’t matter?

Suppose that instead of walking away with a handful of numbers, I was able to produce an image from your data, a picture of the mental template you were using as you performed the task. To get an idea of what I mean, look at these images from a 2004 paper by Kontsevich and Tyler, charmingly titled, “What makes Mona Lisa smile?” The researchers were interested in what aspects of the Mona Lisa’s face influence her famously ambiguous smile. To answer this question, Kontsevich and Tyler took a picture of the Mona Lisa and then added what we call “visual noise,” basically frames of TV static. As you can see from the black and white images, the random noise alters the Mona Lisa’s expression in various small ways. Participants in the study were simply asked to classify whether all these different Mona Lisas looked happy or sad. Once that was done, all of the noise that was classified as making the Mona Lisa “happy” could be averaged together and then laid back on top of Mona Lisa, producing a “happy” Mona Lisa (right color image). Ditto all the “sad” noise, producing a sad Mona (left color image). The basic message? The mystery of Mona Lisa is all in the mouth.

Kontsevich and Tyler managed to produce these classification images very efficiently by layering the noise on top of the picture. But if you wanted to produce a classification image of the Mona Lisa purely from noise, you would need tens of thousands of trials before you started to get something that looked like a woman’s face. This presents a problem for those of us who study perceptual learning, because we usually like to examine how perceptual learning takes shape over the course of a few days. Therefore, we need a way to produce a good classification image purely from noise, and out of one hour’s worth of data. That way we can examine how the image changes day to day.

That’s really the whole point of our paper here: can we find a way to make good classification images from very little data, and if so, can we then analyze the classification image to figure out what, exactly, is changing as perceptual learning occurs?

We decided to apply this concept to a pretty classic task in the perceptual learning field: the detection of an oriented grating in noise. Oriented grating is just another way of saying “tilted stripe”. An hour a day for 10 training days, we’ll have you look at stimuli that are either 100% noise, or a mixture of noise and grating. The grating is always tilted to the same angle, until day 11, when we rotate everything 90 degrees (we call this the transfer session, since we want to see if your learning transfers to a grating of a different angle). In the image below, you see, from left to right, the training grating, the transfer grating, an example of what pure noise looks like, and an example of a noise/grating mixture.

The trick to producing classification images from small amounts of data is to simplify your stimuli as much as possible. In most studies gratings look more like the image at the left, but in our study we’ve eliminated all shades of gray, and kept our stimuli very low-resolution. Each stimulus is just 16x16 pixels, but blown up to about the size of a Post-it note on the screen. This way, instead of each stimulus being composed of several thousand pixels and several hundred colors, ours have just 256 pixels and two colors.

And it works! Here are classification images from one of our subjects for Day 1, Day 10, and the Transfer Day (“T”). As you can see, the classification image is fairly indistinct on Day 1, shows a much clearer stripe pattern by Day 10, and then gets worse again when the orientation is changed for the Transfer session (all images have been rotated to the same orientation for ease of comparison). In case the effect still isn’t clear, the right column applies some extra filtering to the images in the left to enhance the effect. And remember, while all our stimuli used only black or white pixels, the classification images have shades of gray because they represent an averaging of all those stimuli.

Our next hurdle was how, exactly, to measure the “goodness” of each classification image. Our solution was to calculate the Pearson correlation between each classification image and the target grating. In other words, a fairly straightforward measure of how well these two pictures match up, with 1.0 being a perfect score. Once you have that, you can see how the correlations change over time. In our data, image quality clearly improves for about six days, and then levels off. When we change the orientation of the target grating, performance drops back to square one:

My more eagle-eyed readers might notice something ironic about all this. Did we just go through all this trouble to create a classification image, only to convert the image back to a simple number again? But wait, there’s more. What if I created a grating at every possible orientation, and then calculated how well a person’s classification image correlated with each of those? I end up with what we call a tuning function. Ordinarily you can only get those if you’re plugging wires into animals’ brains and directly measuring the activity of their neurons. But have a look:

The red line represents the tuning function for Day 10 classification images. See where the red line intersects with the line labeled “45°”? That’s the equivalent of the Day 10 data point in the previous figure. But because I’ve gone through the trouble of creating this classification image and measuring its correlation with 180 different gratings, I can see much more than a single data point. I can see that there’s a big improvement immediately around the orientation that was trained, but that this improvement rapidly drops off as you move farther from it. In fact, most of the red line is below zero, indicating that the fit between the classification image and these other gratings has actually decreased, or been inhibited.

Then there’s the blue line, which represents the tuning function for Transfer Day. Its spike is 90 degrees away from the red line’s, which you’d expect. But the spike is also smaller and broader, indicating that learning to detect one grating transfers imperfectly to others. Also of interest, you might notice that the blue line has a noticeable “bump” near the spike of the red line. This suggests that even when subjects are told to search for this new Transfer grating, they are using a mental template that is tuned for what they had been trained on previously.

Lastly, no two people are ever going to produce identical classification images, which makes the images useful for revealing individual differences and strategies. Early on in this study, we noticed that some subjects produced very nice-looking images and showed very clear learning trends. Others seemed to produce murkier images and flat or even reversed learning effects (they seemed to get worse over time, not better). What to do with subjects like this is always a thorny question. So, we split the subjects into two groups: learners and non-learners. We found, somewhat surprisingly, that the so-called “non-learners” actually started off with better images than the “learners,” but that they never seemed to improve beyond their starting point. Our analyses showed that the non-learners tended to focus on the center of the stimuli. Their classification images looked like bright blobs, not stripes. It’s a perceptual strategy that worked well for them initially, but failed to generate measurable learning. Meanwhile, the learners started off a bit worse, but seemed to incorporate more of the stimulus into their decisions, and thus produced better classification images. In other words, the non-learners were lazy, and we were able to see and quantify this thanks to the classification images.

That, ladies and gentlemen, is the story: an efficient way to pull a picture out of a person’s brain, and what that picture can tell us about how that person learns. In closing, I’d like to point out that this thing didn’t spring fully formed from our minds. It was accepted for publication as of October, but for three years before that it was a work in progress. More than that, it was one huge learning experience for me. How to program the stimuli, how to design the experiment so that subjects don’t fall asleep in the middle of it, how to detect a cheater, how to analyze the data, how to slice and dice the data, how to ask questions, how to get answers, how to write it up, and how to handle the revisions, all of this was a a learn-on-the-job deal. I’d particularly like to thank my advisor on this project, Aaron Seitz, for all his help and guidance.

I’m taking a class about professional issues in psychological science, in other words, a class in how to be a real scientist. Giving talks is as much a part of the professional life of a scientist as running a lab and applying for grants, so yesterday was talk day. The goal was to give a talk about your research lasting no more than ten minutes, and I hit it on the dot. The talk was generally well-received, which was gratifying, as it will likely evolve into my eventual dissertation defense. Then the professor spoke. “Really great job,” she said, “but, Jon, why should I care about this topic?”

Ah yes. That. I knew I had forgotten something. To be fair, I’m not likely to give this talk to audiences who are utterly unfamiliar with the topic in question, which in this case is something called perceptual learning. But I’m hedging here. I can play devil’s advocate with myself until the sun implodes, but really, I should have just found an extra thirty seconds to explain why my field matters. Good scientists explain their work clearly and concisely. Great scientists—your Carl Sagans, Oliver Sackses, Steven Pinkers, and Albert Einsteins—make the point of their work so obvious and accessible that anyone can understand it.

To the above list of Great Scientific Communicators we should certainly add Dr. Jean Berko Gleason. Dr. Gleason is one of the world’s preeminent psycholinguists, and if you don’t know what a psycholinguist is, I’ll let her explain. All those clips are wonderful (and yes, she is exactly like that in person), particularly for how clearly she explains herself. Multiple branches of nuanced research laid out—zip, boom, bonjour—in half a minute. After watching those clips no one is left wondering why psycholinguistics is an important field. We all understand why Dr. Gleason has allowed psycholinguistics to fill her life, and how it’s relevant in our own.

So what about my field? What’s perceptual learning?

Perceptual learning is a process by which we get better at perceiving things over time. We’re not interested in changes in strategy or decision making (usually), rather, true perceptual learning means that you are literally getting better at seeing. With practice, you can become more sensitive to contrast, motion, or a thousand other things. Take my dentist, for example. Since I’m a graduate student with a bargain basement dental plan, my dental work is performed by fourth and fifth year students at my university’s dental school. Before the end of every visit, a supervising dentist double-checks the student’s work. During one recent checkup, my student dentist told his supervisor that he hadn’t found any cavities in my mouth. The supervisor took one of her tiny metal hooks in hand and glanced it over my molar for what could not have been more than a second. “There’s some decay there. We’ll need to schedule a follow-up to treat it.” She, the experienced dentist, had seen plainly what the less experienced student could not, because her extensive training had made her more sensitive to the tiny precursor of a cavity on my tooth.

It’s not just dentists, of course. Radiologists have to hunt through murky x-rays to find fractured bones and dangerous tumors. Baggage screeners need to be able to spot a knife amongst shampoo and sweaters. Jewelers peer inside diamonds, looking for perfection. Perceptual learning makes the difference between an amateur and an expert.

Perceptual learning is important because it demonstrates that experience and practice can create dramatic change in the brain. If you have a stroke, can we help you recover? Yes. As the developed world grows older on average, what can we do to protect the brain from the ravages of age? Back in ‘86, two researchers showed that you could turn an eighty year old into a twenty year old, given enough practice. We spend increasingly large amounts of time playing video games. Some decry this as a waste of time, a habit fated to create a nation of ADHD-addled zombies. But the science says video games improve our visual capacities. Hell, what are you doing right now? How did you get so good at reading? How are you able to process letters, words, and whole sentences with such blinding speed? In part, reading is a product of perceptual learning.

Over the summer, I participated in a colleague’s experiment, one that involved what’s called a texture discrimination task. Imagine a grid of horizontally dashed lines. Somewhere in the grid, off in your peripheral vision, three of the dashed lines have been turned into diagonal slashes. Sometimes the slashes are arranged vertically in the grid, and sometimes horizontally. The whole stimulus is displayed for a fraction of a second, and your job is to say whether the slashes were vertical or horizontal. On the first day of the experiment, the task was impossible. My performance was so poor that I might as well have had my eyes closed. It was the same story on the second day. After three weeks of training, however, my performance bordered on perfect. The exciting thing, the amazing thing, was that I could feel my perception changing over time. What had once been impossible became trivially easy. The slashes, once as jumbled and fleeting as a snowflake in a blizzard, now jumped out at me as clearly as a snowball in summer.

As scientists we can argue at length about why and how my perception changed. Was it a low-level change in highly specific sets of neurons, or was it a broader change in the way I allocate attention? Will this transfer to other tasks, and what does that mean? Was I detecting the slashes, or filtering out the horizontal lines? It’s easy to get bogged down in the methodology and specifics, and lose sight (har har) of the big picture. Whatever the reasons, there is no doubt in my mind that my perception changed over those three weeks, simply as a result of diligent practice. That’s an amazing thing, a powerful thing. That’s why I do what I do.

Every Psychology 101 course will spend a week or two on the principles of learning. The larger question being addressed is: How can a person’s thoughts or behaviors be changed in an enduring way? In discussing how this question has been studied by psychologists, the lesson invariably starts with the example of Pavlov’s famous drooling dogs and ends with B. F. Skinner and his quirky pigeons. How quirky were they, you ask? Skinner successfully trained his birds to play ping-pong, and even secured military funding to see if he could train them to act as bomb guidance systems. Project Pigeon, as it was called, actually worked, to an extent. True story.

Students don’t have much trouble with the drooling dogs and bombardiering birds. Nor do they have much difficulty mastering the concepts of positive reinforcement, in which you are given something desirable (food, money, etc)to reinforce a target behavior, and punishment, in which you experience something unpleasant whenever you perform an undesired behavior. Confusion doesn’t set in until_negative_ reinforcement is brought up. Negative reinforcement, just like positive reinforcement, increases the likelihood that a target behavior will occur (in contrast, punishment decreases the likelihood of a behavior occurring, and isn’t very good at creating long-term behavior change). The difference is that while positive reinforcement introduces something pleasant to reinforce behavior, negative reinforcement works by removing something unpleasant.It’s a tricky concept to teach because it’s difficult to think of examples in which you’re removing something unpleasant without also introducing something pleasant. As it happens, I’m living just such an example right now.

I am not a morning person. I never have been, and I probably never will be. I am not one for whom the dawn is its own reward. It takes a supreme effort and an elaborate system of alarms to wrench myself out of bed every morning. During holidays my circadian rhythms inevitably slide toward the nocturnal. I eventually find myself falling asleep at 4:00AM and waking up at the crack of noon. Nevertheless, I can count on one hand the number of times I’ve overslept for an early appointment. If I absolutely have to be somewhere at 7:00AM, I’ll be there. It’s just how I was raised.

For the past two weeks I’ve been arriving at the lab by 7:30AM. Initially I did this because I had to; a subject in an experiment I’m running could only come in at 8:00AM. But the subject in question finished up last week, and now I’m coming in early by choice. You may be wondering how I’ve managed to sustain such a miraculous change in my behavior, and believe me, “miraculous” is definitely the word here.

It has everything to do with the B Line. Anyone who lives in Boston knows what I’m talking about. The B Line is by far the slowest, most crowded, and least reliable subway line in the city. That it serves the most densely residential sections of the city but runs the fewest trains is a topic for another day. The end result is that rush hour on the B Line is a nightmare. Moreover, the B Line remains crowded for huge swathes of the day, even as the ridership on other branches of the Green Line thins to almost nothing. The thought of having to stuff myself into a B Line car for what is, all things considered, a short commute fills me with dread.

It turns out that if I can get myself onto the train by, say, 7:00AM, all of these problems go away. The trains haven’t had the chance to get backed up, seating is plentiful, and the ride is quantifiably faster. The whole experience is far less aversive, so much so that I’m actually willing to push against twenty-seven years of night owl habits to change my behavior. Negative reinforcement in action, ladies and gentlemen.

There are positive reinforcers as well, of course. There are more hours in my day and I’m more productive (the only other time in my life where I managed to maintain this schedule also happens to be the time I wrote daily). Since I’m in so early, I don’t feel bad about dodging the evening rush hour by leaving at 4:00. The positive reinforcers are obvious, but it’s the negative reinforcement of avoiding a horrible commute that gets me up in the morning. Skinner tends to get a bad rap these days, but there’s no denying that the man was on to something.

Imagine that it’s 1939 and your country is about to enter World War II. Further imagine that you work for your country’s government, and you have been charged with designing a series of posters with the goal of calming the public in the event of mounting catastrophe. Also, you are British. Immersed in such a situation and thrown a dash of inspiration, you might—I say again, might—come up with something half as brilliant as what was actually designed for this purpose: “Keep Calm and Carry On”.

“Keep Calm” was the final poster in a series of three commissioned by the Ministry of Information. It was intended to be used only if Britain was invaded by the Germans. I mean, really, how stiff upper lip can you get? There you are knee-deep in Nazis and the King’s message to you is simply, “Keep calm and carry on.” Of course, Britain was never invaded and this third poster never saw the light of day (though one supposes that this might have been an ideal message during the Blitz). The poster was forgotten by history until 2000, when an errant copy turned up at Barter Books of Northumberland.

The bold color, stark typography, minimalistic Crown symbol, and wonderfully succinct slogan combined to create something that was both emblematic of the era and perfectly British, all in little more than five words. Suddenly I remembered that the Southerner’s birthday had just passed (don’t look at me like that, he’s not big on presents) and that he has an affection for all things Royal. It became clear that I had no choice but to buy him a copy for his own especial privilege and certain knowledge.¹

Here’s where things get tricky. Crown Copyright on “Keep Calm and Carry On” expired more than twenty years ago. Combined with the poster’s simple design and immense popularity,² this means that there are a lot of knock-offs floating around the internet. All of them feature the Crown, but only some of them use an accurate font. Since the poster is almost all text, the accuracy of the typeface is critical. Barter Books claims to have the original poster. I have no reason to disbelieve them, but some of their merchandise uses a font that is obviously different from the original’s (note the way the letter “C” terminates, as well as differences in the “M”). The match is close, but not close enough, which is deeply confusing. KeepCalmAndCarryOn.com (even more rhyming than the original!) seems to employ the same near-miss typeface, except on the book (weird, right?). Don’t even get me started on the cheap and highly inaccurate reproductions available on Amazon, which appear to use Adobe’s Myriad Pro. While Myriad has the benefit of being free, it looks nothing like the original 1939 letterforms (particularly noticeable on the letters “K”, “C”, and “M”).

So, Mr. Amateur Typographer, you might be thinking, what’s the correct typeface, then? The answer, I think, is that it doesn’t exist. Given the way that posters were produced in 1939 and the limited set of letters that “Keep Calm” employs, it’s more likely that the text was drawn by hand specifically for the job. This means that the only accurate type sample is on the original poster itself. I found one vender on eBay who had gorgeous, accurate prints for sale, but because I live in a disreputable neighborhood the print went missing somewhere between the confirmed delivery and my arriving home. Luckily enough, Wikipedia’s version of the poster appears to be a direct copy of the original, and even better, it’s in SVG format. This means that provided you have a suitable vector graphics application and a decent print shop, you can make your own crisp, typographically accurate copy in any color or size you like. As it happens, I have both, so today I’ll be able to present the Southerner with his long-overdue birthday gift. 24x36 inches big, violently red, and defiantly British.

A few years ago I had to go to the RMV to get my driver’s license renewed. This involved, aside from the paperwork and general atmosphere of human degradation, a quick eye exam. In Boston this is done by peering into what looks like a table-mounted View Master, only instead of slides of the Superfriends, this one has an eye chart.

“Read the letters above the green line, please.”

“X-O-Q-T,” I say. This is followed by a slightly too-long pause.

“And the rest of the line, sir?”

“Oh,” I say, quickly recognizing the problem. I need to turn on my right eye. I squint my left eye shut to give my right eye a jumpstart, and the rest of the line pops into existence. “R-P-V-M.”

Without another word she moves on to the rest of the paperwork. I didn’t get my license renewed that day, but that’s a different story. The point of my telling you this is to let you know that like many people born with cerebral palsy, I have a lazy eye. Or rather, I had a lazy eye, surgically corrected when I was about two years old. As with language, where there’s a sensitive period during which the brain can soak up a native language with ease, there’s a similar period for the wiring of depth-sensitive neurons. This period occurs at a very early time in development, so my depth-sensitive neurons didn’t develop in an ideal manner.

I’ve spent most of my life with this crippling visual disability. Unable to play catch or aim a frisbee. Terrible at estimating how far away I am from anything. And most damningly, utterly unable to shake hands or open doors without accidentally punching someone in the mouth or mashing my fingers against the wall. My hands, they ache from being bitten and bludgeoned so.

Or, you know. Definitely not.

This is why articles like “How 3D Works (And Why It’s Back!)”, by Erez Ben-Ari, never fail to tick me off. They inevitably equate depth perception with stereopsis (literally “solid sight”), a phenomenon experienced when the two slightly different images hitting your eyes merge to produce a sensation of depth (this process is also called binocular fusion¹). In reality, stereopsis is a minor contributor to depth perception, most useful within a range of five feet and essentially useless beyond twenty. The lion’s share of depth perception arises from monocular (one-eyed) cues. We tend to take these for granted since they seem so basic: the way solid objects overlap each other, the way things get smaller as they get farther away, changes in texture and other visible details, to say nothing of a little thing called motion, which always seems to get neglected in discussions of depth perception, academic or otherwise.

Mr. Ben-Ari’s article makes a mistake pretty early on when he claims that “3D imagery has been around for ages, mostly as a gimmick, but things have changed in the past few years.”

Well, sort of. Stereoscopy, or the process of creating a sensation of depth from a pair of 2D images, has been around since 1840. Sir Charles Wheatstone invented the first stereoscope (among a few dozen other things). In fact, Wheatstone’s stereoscope is still used in vision research today, as the apparatus is both cheap and easily adjustable for each observer. You can make one yourself, either with mirrors and cardboard or, if you’re feeling particularly American, with iPods. Even setting the research applications of stereoscopy aside, Ben-Ari’s claim that it’s mostly a “gimmick” is debatable. Any doctor who’s ever gazed into a professional-grade microscope will tell you how useful that extra depth cue can be. Of course, research into stereopsis eventually led Béla Julesz to the random dot stereogram, which in turn gave us the Magic Eye. That’s not just a gimmick, that’s torture. There is no Easter Bunny.

Ben-Ari can also be faulted for failing to do some basic research into the history of 3D movies. Discussing the various methods of projecting 3D movies he says, “…the most popular way, initially, was to use the notorious red-blue glasses…A few years ago, a new delivery method came about, based on polarizer glasses.”

Ben-Ari gives the impression that this polarization technique is all newfangled, arriving on the scene “a few years ago.” I suppose that’s true, if by “a few years,” you mean seventy-four. Polarized 3D movies were patented and marketed by the brilliant Edwin H. Land in 1936. In fact, he started a little Mom and Pop business called Polaroid, perhaps you’ve heard of it? Most of the 3D films shown during the “golden era” of 3D in the 1950s were projected using the polarized method, with the more well-remembered red-blue lens system being used for comic books and later TV adaptations.

All this is window dressing that hides Ben-Ari’s real whopper. After a discussion of the basics of binocular depth perception and before his inaccurate recounting of the history of 3D film, he casually says, “For this reason, people with a damaged eye cannot judge distances correctly.”

Oh, I beg to differ. So would cinematographers, surveyors, and snipers (and anyone who spends a lot of timing estimating distances with one eye shut, really), as well as Bryan Berad, the one-eyed professional hockey player. While we’re on the subject of sports, I found at least three Major League pitchers who are blind in one eye: Thomas Sunkel, who pitched for the Cardinals, the wonderfully named Whammy Douglas, who pitched for the Pirates, and Abe Alvarez, who pitched a few games for the Boston Red Sox during—get ready for it—the 2004 season.People with damaged eyes should be concerned more with their diminished field of view than anything else. Judging distances is not a problem.

Let it also be known that not all “damaged eyes” are equal. If you’re like me and you have some form of amblyopia then not all is lost. Evidence suggests that special visual exercises can restore an amblyope’s visual function to normal levels. At a large vision conference last year, I had the pleasure of meeting Dr. Sue Barry, who showed me that I can even restore my stereopsis, provided I’m looking at the right things. My recent experiences at 3D movies like Up and Coraline have shown me that I am indeed capable of perceiving stereoscopic effects, which suggests that with training I might be able to fully restore my 3D vision.²

So let’s review. Erez Ben-Ari wrote an article on the resurgence of 3D movies in which he botches the science, rewrites history, and fundamentally misunderstands why this resurgence is taking place. It’s not really about improved stereoscopic technology (although it’s certainly easier today than it was in 1936, when two reels of film had to be meticulously synchronized to prevent the audience from dying of eye strain). It’s more about 3D as an attraction. You still can’t get good 3D in your home, which means that the theater is the place to be. For this reason, I doubt we’ll ever see a usable home solution for full-color 3D. If the movie industry hasn’t already gummed up the works on that project, they really should. It’s where the money is. Just look at Avatar.

As games go, Tetris is hard to improve upon. Things like head-to-head play, “obstacle” Tetris, and 3D variations increase the novelty of the experience, but rarely make for a better game than the original 80s action puzzler. I had yet to see a modification of the original formula that actually makes for a better game, until now. Not only is this a pixel-perfect recreation of the classic Nintendo version, but it comes with a simple, brilliant twist that will make you laugh out loud, tear your hair out, and keep you coming back for more. I played Tetris—this exact version of it, no less—for hundreds of hours, and yet with this one simple change, the entire experience is fresh again. That’s quite an accomplishment.