The purpose of this study was to determine whether tactile laterality effects can be attributed to an anatomical pathway-transmission model or to some hemispheric mechanism involved in the perception and/or mediation of activities in the contralateral hemispatial field. Hemispace is not the same as the visual half field, but refers to the external space to the left or right of body midline. To differentiate between these two hypotheses, 24 normal dextrals performed a tactile line bisection task using the left or right hand in each of three spatial conditions: at midline, in left hemispace and right hemispace. The findings indicated that both hemisphere-hemispace mechanisms and hemisphere-hand connections contributed to laterality effects. Furthermore, a pseudoneglect phenomenon was observed. © 1980.