A new research study discovers that humans can improve their ability to see things in rapid succession.
Traditionally, psychologists believed humans were unable to perceive things in the very rapid succession of, say, less than half a second. They called this limitation the “attentional blink.”
For example, we will notice a car spinning out in our path, but maybe not register a second car immediately beyond it.
In the new study, researchers discovered we can overcome the blink with some training — an approach that was never been tried before.
“Attention is a very important component of visual perception,” said Takeo Watanabe, a professor at Brown University.
“One of the best ways to enhance our visual ability is to improve our attentional function.”
Experts learned that if they make the second target object a distinct color they could train people to switch their attention more quickly than they could before.
After that, they can perceive a second target object presented as quickly as a fifth of a second later, even when it isn’t distinctly colored.
In the first and most important experiment, the researchers sat 10 people down at a computer and showed them a rapid-fire sequence of many white-on-black letters and just two white-on-black numbers.
The characters would appear and disappear within a tenth of a second.
People were then supposed to type the numbers they saw. In one set of sequences the numbers were spaced only two characters, or a fifth of a second, apart.
In another set the numbers were spaced apart by six characters, or more than half a second. People performed hundreds of rounds of each task.
Before training, which also lasted hundreds of rounds, people were much more likely to get the second number right when it was presented more than half a second after the first. If it was presented less than half a second later, there was a measurable attentional blink effect.
To train people, Watanabe and his team made only one difference: they colored the second number red.
“A color change can be very conspicuous,” Watanabe said. “If all items are black and white and all of a sudden a color item is shown, you pay attention to that.”
After training, the researchers went back to presenting the subjects with the same kind of black and white letter-and-numbers sequences for two more days.
In the more rapid sequence, the trained subjects were able to get the second number right much more often, almost exactly as during the sequence with a longer time between numbers.
Amazingly, attentional blink was almost completely gone.
In subsequent experiments they found the perception performance increase was still in place as long as two and a half months after training.
Furthermore, the effects of training were shown in successive experiments to take hold even when the experimenters varied the time interval between the first and second target numbers, and when the numbers were masked not by letters, but instead by gibberish characters.
Investigators then performed the original experiment with nine volunteers in an fMRI machine to see what was going on in the brain before and after people received training.
The goal was to see if training helped them process quicker targets like they do with the more slowly spaced targets or whether they pay attention differently.
If the improvement came from processing, the researchers reasoned, they’d expect to see to brain activity when handling the more rapid sequence bear a greater resemblance to the brain activity during the slower sequence.
Instead they saw no such increased correlation in four parts of the brain.
This meant that people were deciding to switch their attention more quickly after training, rather than processing the visual stimuli faster.
“Attention is a cognitive component of visual perception,” Watanabe said.
“We have shown that even a higher cognitive component of visual processing can be improved.”
Watanabe and his team discuss their findings in a paper published in the Proceedings of the National Academy of Sciences.
Source: Brown University