Abstract
The suitable projection is important for students to misunderstand a drawing. The author has been carrying out the recognition tests to reveal the suitable direction of projection. In the present study, two results of cognizing test carried out in 2002 and 2016 are statistically analyzed to discuss the time dependency on the directivity of the visual recognition. Although the significant differences cannot be recognized between these tests, rather inappreciable differences can be observed especially on the parameterφof the random display test which includes the distribution shapes of the points. These differences may be caused by the reason that the subjects of two tests were not strictly the same and the tests were conducted by using the figures in which parameters θ and φ were chosen by 15° interval. Thus the directivity of the visual recognition is essentially independent of the time of testing. Moreover, normal distribution of the parameter of the figure indicates that the directivity of the visual recognition is dominated by the natural law.
