LEFT-HANDERS SMILES - ASYMMETRIES IN THE PROJECTION OF A POSED EXPRESSION

Asymmetries in the expression of a posed smile and in a relaxed facial expression were observed in 24 left-handers. Neither writing position nor familial sinistrality predicted the variance of the results. Left-handers were found to smile more with their left than right side of face; an asymmetry which had previously been observed in right-handers. If anything, left-handers' smiles were more asymmetric, though in the same direction, than right-handers. When relaxed, however, the left-handers' face was judged more unhappy on its right than left side — a reversal of the direction of asymmetry previously noted in right-handers' relaxed expressions. No single neurological or psychological theory accounts for these results; it is suggested that hand preference may exert a myotonic effect which is reflected in judgements of relaxed facial expressions. © 1979, All rights reserved.