Construction errors as a key to perceptual difficulties encountered in reading technical drawings

A large number of subjects drawn from a variety of populations was required to build simple models in response to diagrams. Their responses were evaluated with especial reference to the errors made. It seems that the errors were largely due to misperception of the drawings and therefore show what difficulties people are likely to find when required to use technical drawings. These difficulties range from inability to perceive elementary units correctly (a weakness characteristic of the least educated/sophisticated subjects) to inability to group the relations among such units. Examples of errors made are discussed and their significance for training in the usage of technical drawings stressed.