Recent research suggests that (in right-handed people) clenching your right hand might help you form stronger memories and clenching your left will help recall memories.
According to Dr. popper and her colleagues “unilateral hand clenching increases neural activity in the frontal lobe” and thus helps with memory forming and retrieval.
I asked Dr. popper if the same or the opposite sequence of clenching works for left-handed people. Her response:
There is some research showing that non-right-handers are not the opposite of right-handers. In fact, there is some possibility that clenching the same as righties would be harmful to non-righties memories, and no idea what would happen for opposite hand clenching. An educated guess would suggest there would not be help for memory.
Read the full article: “Getting a Grip on Memory: Unilateral Hand Clenching Alters Episodic Recall”