Guiard's Theory of Asymmetric Bimanual Action

Yves Guiard's 1987 model describing how the two hands typically take complementary, asymmetric roles in everyday manual tasks. The non-dominant hand sets a coarse spatial frame of reference that the dominant hand operates within, the non-dominant hand precedes the dominant hand in action, and the dominant hand works at a finer temporal and spatial scale. The theory has been foundational in human-computer interaction design and is particularly influential in accessibility research on tactile exploration, where it explains why BLV users benefit from one hand anchoring while the other traces contours, and why assistive tools that force both hands off the object collapse the user's spatial reference.