Several studies have confirmed this bizarre proposition: If you’re taking a test of rote memorization, like words from a list, move your eyes from side to side for about 30 seconds before you start. Really.
Researchers have found, with relative consistency, that if you saccade from left to right and back several times before a test of simple recall, you’re likely to do better. Why? It may be that this quick activity helps facilitate interaction between the brain hemispheres. Since split-brain patients have more difficulty recalling words than people with normal brains, any activity that encourages communication between the hemispheres is likely to increase recall.
If improving communication between the brain’s hemispheres is at the root of this seemingly bizarre effect, then a team led by Keith Lyle reasoned that people who have poorer interactions between the hemispheres should benefit more than others. Who has less interactions between hemispheres? People who are strongly right-handed. Handedness is actually not binary: Many people eat with the left hand, for example, but do everything else right-handed. A simple test can give you a sense of how dominant one hand or the other is. You can try an online version of the test here. Go ahead, give it a shot.
The results are expressed from -100 (completely left-domininant) to +100 (completely right-dominant). How do our readers do? Let’s make this a poll:
Lyle’s team used the same scale to test 142 college students for handedness. Those who scored higher than +80 on the test were categorized as strongly right-handed. Everyone else was put in a non-strongly-right-handed group.
Then the researchers asked them to memorize a list of 50 words that were flashed up on the screen for 2 seconds at a time. Then half the students watched for 30 seconds as a dot flashed alternately on the left and right side of the screen (they were instructed to keep their head still and follow the dot with their eyes). The other half watched a dot change color in the middle of the screen. Then they were asked to write down as many of the words as they could remember. Here are the results:
Strongly right-handed students remembered significantly more words if they moved their eyes compared to keeping their eyes still. Non-strongly-right-handed students (including left-handers) remembered the same number of words regardless of whether they moved their eyes before the test.
But there’s another aspect to memory: how many words did respondents incorrectly think they had seen? Here are those results:
Once again, strongly right-handed students had significantly fewer false alarms after they moved their eyes back and forth. But for non-strongly-right-handed people, the reverse occurred; moving their eyes caused them to falsely remember more words. So overall, while the eye-saccade exercise helped right-handers, for lefties and for those who didn’t have a strongly dominant hand, the exercise actually harmed their performance.
A second study confirmed these results and added another bizarre twist. You might think that only side-to-side movement would improve performance, but Lyle’s team found that moving your eyes up and down caused the same effect. This might seem to strike a blow for the hemispheric connectivity argument: the right and left visual fields are represented in different hemispheres of the brain, but up and down are not. But the researchers say that other studies have shown that any eye movements increase bilateral activity in the frontal eye field, so it’s still possible that hemispheric connectivity can explain the improved performance after eye movements.
So why doesn’t the exercise work the same way for left-handers? Left handers (and ambidextrous individuals) already have a high level of hemispheric connectivity. Lyle’s team speculates that there might be such a thing as too much connectivity, which results in a decrease in performance.
But if you scored higher than +80 on the handedness questionnaire, the results seem quite compelling: on tests of simple recall, doing this simple eye exercise beforehand might improve your score.
LYLE, K., LOGAN, J., & ROEDIGER, H. (2008). Eye movements enhance memory for individuals who are strongly right-handed and harm it for individuals who are not Psychonomic Bulletin & Review, 15 (3), 515-520 DOI: 10.3758/PBR.15.3.515