Hull, C. L. (1928). Anatomical and Other Alleged Signs of Aptitude. In C. L. Hull, Measurement and adjustment series. Aptitude testing (pp. 111-155). Yonkers-on-Hudson, NY, US: World Book Company.
http://dx.doi.org/10.1037/11019-004
In the preceding chapter we have considered various types of aptitude tests. We have now the task of examining a number of approaches to aptitude prognosis which, while distinctly allied to tests, should probably be regarded more as signs. (PsycINFO Database Record (c) 2016 APA, all rights reserved)