“…Comparisons of manual and oral systems have suggested that in young (Jacobs, van Steenberghe, & Schotte, 1992;Loucks et al, 2010;van Steenberghe, Bonte, Schols, Jacobs, & Schotte, 1991) and middle-aged (Gentil & Tournier, 1998) adults, the oral effectors are optimized for speed, and the manual effectors for accuracy and load bearing. This differentiation is apparent even in preschool, but while children's strength and accuracy improve with age in both effectors, the variability of constant force production improves only in the hand (Potter, Kent, & Lazarus, 2009).…”