Journal for Geometry and Graphics Volume 8 (2004), No. 1, 117–126. A Mental Cutting Test Using Drawings of Intersections Emiko Tsutsumi School of Social Information Studies, Otsuma Women’s University 2-7-1, Karakida/Tama, Tokyo 206-8540, Japan email: tsutsumi@otsuma.ac.jp Abstract. In order to examine the role of information processing in recogniz- ing 3D-objects using 2D-projection drawings, a standard paper-pencil MCT was administered to female students, who were instructed to draw intersecting lines on the projection chart of a test solid before selecting alternatives. As a result, it is quite possible that the ability to draw intersections itself is related to the score of the MCT, as well as to spatial ability. However, it did not seem possible to stimulate the sense of recognizing 3D-objects through the process of drawing intersections directly on to the test solids. Thus we concluded that most of the subjects who made low scores in the MCT, couldn’t envision the space itself that contained three-dimensional objects when they observed projection drawings. Key Words: Mental Cutting Test, intersection, spatial ability MSC 2000: 51N05 1. Introduction In recent years, 3D spatial abilities have received much attention and the Mental Cutting Test (hereafter MCT), a sub-set of the CEEB Special Aptitude Test in Spatial Relations [1] (1939), has been used by Suzuki et al. [3] to measure spatial abilities in relation to graphics curricula. The ‘standard MCT’ consists of 25 problems. In each problem, subjects are given a per- spective drawing of a test solid, which is to be cut with a hypothetical cutting plane. Subjects are then asked to choose one correct cross section from among 5 alternatives. There are two categories of problems in the MCT [3]. Those of the first category are called ‘pattern recogni- tion problems’, in which the correct answer is determined by identifying only the pattern of the section. The other are called ‘quantity problems’ or ‘dimension specification problems’, in which the correct answer is determined by identifying not only the correct pattern but also the quantity in the section, e.g., the length of the edges or the angles between the edges. ISSN 1433-8157/$ 2.50 c  2004 Heldermann Verlag