Genetic vs. environmental contributions to human handedness: insights gained from studying individuals with unilateral hand injuries.

Four hundred eleven individuals who had suffered temporary unilateral hand injuries were assessed on five hand preference behaviors after their recovery. Measures of shifts to contralateral hand use experienced during and after the recovery period were taken. The best predictor of hand use shifts during the injury recovery period was whether the injury was to the preferred or nonpreferred hand. The incidence of postinjury contralateral shifts was low but was greater than that observed over a simulated injury period in a control group of 384 individuals who had not experienced a hand injury.