Reading and a balanced polymorphism for laterality and ability.

The idea that reading ability might vary with right-left hand skill, such that children with mild biases to the right hand have advantages for learning, while children at both left and right extremes have disadvantages, was supported by findings for a large sample of primary schoolchildren. Poor readers tended to have weak left hand skills, giving strong right hand preferences in many cases. Those with additionally poor right hand skills tended to be of low intelligence. Good left hand skills and raised incidences of mixed and left hand preference were found only in a small subgroup, "bright dyslexics".