I've long been a believer that educational/school psychologists need to pay more attention to non-cognitive variables (conative abilities) when discussing a student's aptitude for school learning. A major barrier to attending to these abilities has been a shortage of empirically based conceptual/theoretical models and practical measures.
Although there is still a clear void in the area of practical measurement tools, significant progress has been made the past 10 years in the development of theoretical models of important conative abilities. Two books are suggested for those who want to learn more.
First, and probably the most difficult read, is Remaking the Concept of Aptitude: Extending the Legacy of Richard Snow. This posthumously published book, in honor of Richard Snow, provides (in one place) a summary of the "state of the art" of Snow's work on aptitude...which, in simple terms, requires an integration of cognitive and conative abilities into a coherent theoretical framework. The reader is forewarned---this book shows the signs of being authored by committee. At times it is not coherent, material is not well linked, and it becomes difficult to see the forest from the trees.
The recently published Handbook of Competence and Motivation (Elliot & Dweck, 2005) represents a monumental integration of the emirical/conceptual progress made during the past few decades regarding to the most salient conative abilities (e.g., achievement goal orientation, self-theories, self-regulatory learning processes, etc.). Having recently spent the better part of 2 years searching for contemporary research in the diverse domain of conative abilities, I believe that this edited volume provides the best contemporary integration of this vast literature. An expensive book (yes, I know..."tell me something new"), but probably the best single integrative work I've seen to date.
Hopefully these books will stimulate the development of applied measures that can narrow the theory-practice gap.