When Machiavelli wrote The Prince, his stated goal was to distill useful information from history for his patron and, in a compact form, provide practical knowledge about how to govern effectively. Unfortunately, few textbook authors have Machiavelli’s talent for summary, let alone his ability to rise above his sources. Textbook presentations of grand old theories, necessary as they are, often amount to decontextualized lists, stripped of what made these works compelling in the first place. What is quickly presented, is too often quickly forgotten. Of course, like C.S. Lewis’s description of the power of myths, some theories are compelling no matter how dull the presentation.
At times I too present concise summaries of historical theories of intelligence but I think that there is no substitute for reading the historical sources for oneself. Pick just one old theory of intelligence, read the original sources thoroughly, and see what happens to your thinking.
I do not wish to give the impression that reading these works is the most efficient manner of learning useful information. If the goal is simply to find the most information-dense sources of practical knowledge available, one should probably stick to contemporary works of scholarship. Alongside the conceptual breakthroughs that made certain older works noteworthy, there are lesser ideas and also (sometimes charming, sometimes distasteful) informational clutter.
A difference kind of mindset and a patient, slower pace are required while reading these sources—but something hard to describe happens when they are encountered directly. The ideas we discover in our explorations of history—they are not only more memorable because they are embedded in personal stories and the overall narrative of the field—they become unforgettable because they work their way into our identity as psychologists.
In every culture, perhaps the most important function of history is to create a sense of group identity amongst otherwise unrelated people who need to cooperate for the common good. In the United States, for example, we tell tales about Washington, Jefferson, and other founders, and in so doing come to feel committed to the core ideas and ideals of our republic. When we come to know and care about Abraham Lincoln, Susan B. Anthony, and Martin Luther King, Jr., we refine and broaden our sense of group identity.
Although there are indeed heroes and villains from the history of our discipline, most contributors cannot so easily be categorized; there is both wisdom and folly embedded in their stories and in their ideas. When we learn who they were and what they thought, not only are we able to learn useful information, their values and their concerns inform our values and our concerns. Even their mistakes are instructive and help us acquire much-needed humility. When we know and cherish the stories of how individuals in our discipline have committed themselves to the betterment of our field, we are inspired to do likewise.
Even quirky old theories with deep flaws are worth studying. Usually, a quirky theory was developed by a quirky person with quirky concerns. However, just as we value demographic diversity in the classroom, there are good reasons to value diversity of thought in the theoretical domain. That is, with a bit of empathy, exposure to those odd concerns can often provoke creative thoughts relevant to currently overlooked problems.
These various theories, old and new, were and are rivals to some degree. But they also were and are part of a grand collaborative process in advancing our understanding of cognitive abilities. Typically, the differences between the theories are not so much due to mutually exclusive positions but mostly due to different emphases. We study diverse theories not so much to figure out which is the right one but we learn from each theory a new set of cognitive tools with which we can unlock new mysteries both at the broad theoretical level and at the point of contact with individuals who need our help.