New research suggests making a fist with your hand is not necessarily a sign of exasperation, rather a memory recall method.
Investigators also discovered a differential between upper extremities as squeezing your right fist may help form a stronger memory of an event or action, and clenching your left may help you recollect the memory later.
The study, by Ruth Propper and colleagues from Montclair State University is published in the open access journal PLOS ONE.
During the research, participants were split into groups and asked to first memorize, and later recall words from a list of 72 words.
There were 4 groups who clenched their hands; One group clenched their right fist for about 90 seconds immediately prior to memorizing the list and then did the same immediately prior to recollecting the words.
Another group clenched their left hand prior to both memorizing and recollecting. Two other groups clenched one hand prior to memorizing (either the left or right hand) and the opposite hand prior to recollecting. A control group did not clench their fists at any point.
The group that clenched their right fist when memorizing the list and then clenched the left when recollecting the words performed better than all the other hand clenching groups. This group also did better than the group that did not clench their fists at all, though this difference was not statistically ‘significant’.
Researchers say the findings suggest that simple body movements – by temporarily changing the way the brain functions – can improve memory.
“Future research will examine whether hand clenching can also improve other forms of cognition, for example verbal or spatial abilities,” says Ruth Propper, lead scientist on the study.
The findings are preliminary as the authors call for future work to test whether their results with word lists also extend to memories of visual stimuli – like remembering a face, or spatial tasks, such as remembering where keys were placed.
Researchers believe this effect of hand-clenching on memory may result from cognitive overspill as clenching a fist activates specific brain regions that are also associated with memory formation.
