Document Type


Publication Date

Spring 4-3-2013

Journal / Book Title

Plos One


Unilateral hand clenching increases neuronal activity in the frontal lobe of the contralateral hemisphere. Such hand clenching is also associated with increased experiencing a given hemisphere’s “mode of processing.” Together, these findings suggest that unilateral hand clenching can be used to test hypotheses concerning the specializations of the cerebral hemispheres during memory encoding and retrieval. We investigated this possibility by testing the effects of a unilateral hand clenching on episodic memory. The hemispheric Encoding/Retrieval Asymmetry (HERA) model proposes left prefrontal regions are associated with encoding, and right prefrontal regions with retrieval, of episodic memories. It was hypothesized that right-hand clenching (left hemisphere activation) pre-encoding, and left-hand clenching (right hemisphere activation) pre-recall, would result in superior memory. Results supported the HERA model. Also supported was that simple unilateral hand clenching can be used as a means by which the functional specializations of the cerebral hemispheres can be investigated in intact humans.


DOI: 10.1371/journal.pone.0062474

Published Citation

Propper, Ruth E., Sean E. McGraw, Tad T. Brunye, and Michael Weiss. "Getting a grip on memory: Unilateral hand clenching alters episodic recall." PloS one 8, no. 4 (2013): e62474.