Predicting from the right shift theory

Inter-limb Coupling in Coordinated Bimanual Movement: Attention and Asymmetries

Inter-limb coupling, a phenomenon whereby each of the upper limbs tends to take on characteristics of the intended movement of the other, represents a limitation on the ability to perform asymmetrical bimanual movements. Two experiments each employing 16 dextral and 16 sinistral normal subjects are reported. In the first experiment evidence of inter-limb coupling was observed during a continuous bimanual rotary task. This coupling appeared to be asymmetrical, with the nonpreferred hand contributing more to coupling than the preferred hand, especially in dextrals. In the second experiment asymmetries in inter-limb coupling were found to be modified by the conscious direction of attention to one or other hand. This suggests that the often reported strong inter-limb asymmetry associated with dextrality, and the weaker assymetry associated with sinistrality, may be partly due to an underlying inter-limb attentional asymmetry in the former, and a relative lack of attentional asymmetry in the latter.

Handedness in extremely low birth weight infants: aetiology and relationship to intellectual abilities, motor performance and behaviour at four and six years

Hand preference was measured in a total group of 71 ELBW children to determine patterns of hand preference at 4 and 6 years, possible aetiological factors leading to handedness, and whether left or non right hand preference were markers for intellectual, motor, temperament or behavioural differences. At both 4 and 6 years the prevalence of left handedness was increased, though this prevalence changed over the period of the study. Results supported brain injury as one mechanism leading to increased left hand preference, though this process did not adequately explain this increase. Possible reasons for this and the apparent change in prevalence with time are examined. Mixed handedness at 4 years was associated with lower intellectual abilities though otherwise children were similar in motor skills, temperament and behaviour independent of hand preference category.