“…Studies of spatial ability trace back to the 1920s, when a "practical" or "mechanical" aptitude separate from Spearman's general intelligence factor was first proposed (Smith, 1964). The multiplicity of spatial factors that resulted from early factor analysis studies (Slater, 1940;Guilford and Zimmerman, 1947;Guilford and Lacy, 1947;Thurstone, 1950;French, 1951;Guilford, Fruchter, and Zimmerman, 1952) was eventually reduced to two major factors: spatial orientation and spatial visualization (Michael, Guilfor, Fruchter and Zimmerman, 1957). Spatial orientation has been described as the ability to remain unconfused by changing orientations in which visual stimuli are presented, while spatial visualization invol-\tes the ability to mentally manipulate pictorially presented stimuli by a process which involves recognizing, retaining and recalling configurations in which there is movement of the figure or parts of the figure (McGee, 1979).…”