Many scholars in the field of individual differences believe that most of the real-life significance of ability tests derives from a single dimension of general intelligence, which sometimes takes the form of a g factor or a set of IQ scores.
In response to this, Foundation researchers have attempted to demonstrate that aptitudes involve more than a single continuum of talent. In Memory for Design: An Overlooked Mental Ability, Chris Condon and David Schroeder showed that the Foundation's Memory for Design test is related to a number of external criteria including years of education, quality of undergraduate institution, choice of college major, and choice of occupation. To address the issue of general intelligence, they derived a general-ability factor from the Foundation's standard test battery.
When they statistically controlled for this factor in the Memory for Design scores (that is, they removed the general-factor-related variance in the scores), the Memory for Design scores still showed important relationships with the external criteria. The relationship with choice of major is shown in the accompanying figure.
As can be seen, the portion of Memory for Design that is unrelated to general ability shows sizable differences among majors, with Engineering and Architecture scoring relatively high and Humanities and Foreign Languages & Literature scoring low. This analysis specifically speaks to the pertinence of aptitude measurement for college students.
An overall score for g or IQ may not provide any guidance regarding whether to major in, say, Engineering or Humanities, but as shown here, specific aptitude scores such as Memory for Design provide information that is important in making these choices.