Fist clenching could signal tension or default for fight mode but scientists actually wondered whether the act of clenching your fists relayed certain regions of the brain responsible for retrieving and encoding information to boost memory.

A new study suggests it does.

Psychologists gathered 51 right-handed participants and asked them to clench a rubber balls for 90 seconds prior to reading 36 words, then they were told to clench and write down as many words as they could remember.

They found that those who clenched with their right hand then clenched their left hand to write remembered more words, compared to those who squeezed with left then the right or just squeezed once.

"In total, these results are striking," the authors said. "Given that the manipulation used a total of 90 seconds of unilateral hand clenching pre-encoding and pre-recall is easily adaptable to a variety of experimental, clinical and real-world situations."

Previously, lead author and Associate Professor of Psychology at Montclair State University Ruth Propper studied improving the memories of soldiers, using unilateral gazing to determine whether the left or right side of the brain, even the combination of both, recollected language and location-related memories so the soldiers could recall places to safely navigate in unfamiliar territories.

"In practical terms, this means if you can't remember where you parked your car, our study suggests you could look to the left to activate the right side of your brain's spatial processing superiority or possibly look to the right to trigger the left side of the brain's verbal labeling superiority and retrieve that memory," Propper said about the past study.

"We are looking at how novel physiological markers might predict performance on various cognitive tasks-like remembering place names and locations. We're also looking at new ways to improve performance by altering physiological activity," she said. "Unilateral gaze is one way we investigate this. Another is to study unilateral muscle contractions to see if they might activate brain areas involved in memory retrieval."

This study, partially funded by the United States Army, revealed that fist clenching could specifically increase brain activity in the opposite hemisphere, which they measured using an electroencephalogram. Looking ahead, researchers hope to measure more brain activities to validate whether it could improve memory.

The research appeared in PLOS ONE journal on Thursday.