When we’re in a crowded space, making visual judgments becomes more difficult. But it doesn’t take much to trigger a crowding effect. Clicking on the picture below will take you to a quick movie (QuickTime required) that should demonstrate the effect. Focus on the cross to the left, then start the movie (it may start automatically, depending on your browser). In two seconds, a “T” will flash briefly on the right side of the screen. Your job is to determine whether the T is upright or inverted (upside-down). After another two seconds, three Ts will appear. This time, you must judge only the middle T, which appears in the same place as the first T you judged.
If you don’t get the hang of it the first time you watch, go ahead and watch the movie one more time — but no more! Which T was more difficult to judge? Because the second T was “crowded” by the other two, it should be more difficult for most people. The two polls below should indicate whether we found the effect — I’ll give the correct answers at the end of this post.
It’s difficult, isn’t it? So, is there any way to improve our performance in these crowded situations? C.S. Green and D. Bavelier have conducted several studies on video games and vision (here’s one we’ve discussed), finding that action games improve vision in a number of different ways. Can games help on the crowding task?
Green and Bavelier tested 14 avid gamers and 14 non-gamers, all males, on a task similar to the one I demonstrated above. First they tested viewers on Ts alone, showing progressively smaller Ts until responses were no longer accurate. Even on this task, with no crowding, the gamers were able to respond accurately to smaller Ts than non-gamers. For the crowding task, each viewer was tested on objects at the center of the visual field, 10° from the center, or 25° from the center. The Ts used in this task were 1.5 times larger than the smallest T each individual viewer could accurately judge alone. The three Ts were moved progressively closer together until, again, respondents failed to answer correctly.
[Actually the researchers used a "staircase" design, which means that when an answer was correct, the next set of Ts would be closer together. When it was wrong, the next set was farther apart. Eventually each viewer settled in on a point where he was alternating between correct and incorrect responses]
Here are the results:
No matter how far from the center of the visual field the Ts appeared, the gamers could judge them in more crowded conditions than the non-gamers.
But perhaps people with better vision are simply more likely to become avid gamers, since good vision might make them more likely be be good at the games. So Green and Bavelier recruited 32 students who were non-gamers and gave them a shorter version of the same test. Then the students practiced either on Unreal Tournament or Tetris for a four- to six-week period, a total of 30 hours of game play. After training, those who had played Unreal Tournament scored significantly better on the test, while those who played Tetris showed no improvement. It appears that the video game training was indeed responsible for the improvement in vision.
Even though they’ve found similar results before, the researchers say this result is special because it shows that even when the location of the object viewers are tested on is known in advance, there’s still an improvement in visual ability associated with game play. Where previous studies focused mainly on visual search tasks, this study demonstrates the spatial resolution of vision can also be improved by playing video games. Green and Bavelier suggest that gaming might be used as therapy for older adults whose vision often fades in precisely this domain.
Now, how did our readers do on the crowding task? The first T was upside-down, and the second T was right-side-up, so if we’ve replicated the effect, then “upside-down” should be the most common response to the first question, while for the second poll, responses should be closer to 50-50.
C.S. Green, D. Bavelier (2007). Action-Video-Game Experience Alters the Spatial Resolution of Vision Psychological Science, 18 (1), 88-94 DOI: 10.1111/j.1467-9280.2007.01853.x