The effects of hand preference side and hand preference switch history on measures of psychological and physical well-being and cognitive performance in a sample of older adult right-and left-handers

Claims have been made that left-handedness often arises from pathological causes, and that owing to this underlying pathology, the presence of sinistrality may entail disadvantages for both the length and quality of life. A prime implication of these claims is that left-handers, as a group, should display signs of poorer fitness than right-handers. This poorer fitness might take the form of an increased incidence of illnesses and/or accidents. In addition, it might also be predicted that left-handers would experience a psychological and, perhaps, cognitive quality of life that is inferior to that of right-handers. In the present study, we measured a large sample (N=1277) of older adults on four indexes of lateral preference (hand, foot, eye, and ear), on whether or not they experienced pressure to switch their preferred writing hand, and variables related to psychological well-being, physical health, and cognitive performance. The results revealed that the presence of left hand writing, in isolation, did not predict decreases in quality of life factors; however, in conjunction with left-handed writing, the presence of a hand preference switch report was shown to be important. In particular, one subset of left-handers - those who attempted to change their preferred writing hand but were unsuccessful - was found to have a lower quality of psychological and physical well-being on multiple measures.