Factors which influence the difficulty of the spatial path in Corsi's block-tapping test.

Spatial path in Corsi's test is defined as the ideal line joining the blocks tapped by the Examiner so the difficulty of the spatial path was analysed vis-á-vis the numbers of blocks tapped by the Examiner and the number of times the line criss-crosses itself through the spatial path. During an experiment with two different numbers of blocks and three different numbers of crosses, an analysis of variance showed that both factors, i.e., the number of blocks and the number of crosses, gave significant results. The experiment showed that it is possible to create a series with a decreased number of blocks, but with an increased number of crosses, which was more difficult than a series with a greater number of blocks but with a decreased number of crosses. Despite this, additional significant differences have been found among the series with the same number of blocks and crosses, meaning that the variables examined, although important, do not solve the problem with the complexity of the spatial path. At this stage, the length of the path, measured in millimetres, had to be considered as a further source of variance which could explain the difficulty of the spatial path. The correlation between path length and mean number correct achieved, through a single series of digits utilised in this research, was -.78. This value encourages further research.