It is argued that, what is needed for a test, is not necessarily
also what is measured by the test.
For most intelligence test problems, the sense of sight is needed,
But nobody would argue that, as a result, the test measures the
sense of sight. In a similar way, it is true that for most
intelligence test problems abstract reasoning is needed. But many
psychologist conclude, that, consequently, the test measures abstract
reasoning. Similarly, many tests require verbal comprehension, and
psychologists argue again that, as a result, these tests measure verbal
ability. A similar argument is used with regard to spatial
perception. Furthermore, the proposition is defended, that
the correctness of a response and the time needed is not necessarily
determined by an underlying quantitative ability
Giving an incorrect response could be the result of a lack of
knowledge or of the use of a certain test taking strategy, the latter
being determined more by motivation than by ability. The time needed
to solve a certain test item may be long due to a lack of familiarity
with the task or to casual blockings in the proces of memory search.
Finally, a completely new test paradigma is proposed, which guarantees
the measurement of unitary, quantitative factors, which determine the
speed and constancy of mental work. These factors stem from a theoretical
explanation of mental tasks, in which confounding factors, such as
knowledge, experience, and motivation are ruled out.