Dewey's impact on American education is huge, particularly in the arena of teacher training. That said, the name "John Dewey" or "Deweyean" is really a synechdoche often used to refer to the larger field of "constructivism," of which Dewey was merely an adherent.

Just as Dewey stands among other pragmatist philosophers such as William James and CS Peirce and later WVO Quine and Richard Rorty, so too does he stand among a large group of pedagogical constructivist philosophers such as Lev Vygotsky, Maria Montessori, and (the grandpappy) Jean Piaget.

In many ways, the constructivist theory of knowledge is the epistemological wing of pragmatism. Constructivism holds that knowledge is built or compiled (i.e. "constructed") by knowers, rather than being an objective "thing" out there in the world waiting to be discovered or deduced. This aligns very closely with many of the pragmatic theories of truth and knowledge, particularly those promoted by William James in both Pragmatism and The Meaning of Truth. (An interesting note: James was a trained psychologist, as was Piaget. As such, both of their respective theories of knowledge emerged from observation of others, rather than speculation about themselves. In this way, one of the methodological assumptions of pragmatism -- i.e., discover stuff by looking at others -- flies in the face of Enlightenment and pre-Enlightenment-era epistemologies, most notably those present in Rene Descartes' Meditations, John Locke's Essay Concerning Human Understanding, and David Hume's Treatise of Human Nature. Both Locke and Hume did regard their work as psychological, rather than philosophical, though both used themselves as their "case studies.")

The tenets of educational constructivism emphasize student-centered learning, co-creation of knowledge, the teacher-as-facilitator or co-learner model, and so on. Dewey's contribution to these tenets is his personal emphasis on learning by doing. In his pedagogical magnum opus Democracy and Education, a point he iterates and reiterates is the importance of making the process of education as close to the process of living as possible. That is, education should not exist solely in the abstract. As such, he promoted what would be called today "project-based learning," though he didn't coin that term. By completing projects, students directed their own learning by collaborating with each other. The teacher steps back, only offering guidance when asked to do so. The pace of the learning is determined by the pace at which the students work in their attempts to complete the project. Assessment is holistic, considering both the relative success with which the project is completed, as well as the relative skills and knowledges the students develop during the course of completing the project.

This type of project-based, constructivist project is, as Dewey, Piaget, and any other educational constructivist will argue, the best way for education to happen because this is exactly how learning and knowing happen. And, up until about five or so years ago, this is what teachers throughout the states were taught was the best way to teach and learn.

Then, No Child Left Behind, and the re-introduction of standardized testing as a method by which student achievement is assessed. This has a ripple effect on teaching and learning practices. To be cartoonish about it, if assessment is no longer holistic, then learning can no longer be project-based. This is a return to a more didactic form of education, one in which knowledge exists out there in the world and it is the job of the teacher (read: expert) to clarify that knowledge and put it into the heads of her students.

Testing is by no means new. And I should be clear here that when I use the word "testing" I am referring to "standardized testing," and not the types of testing that an individual teacher uses in his or her own classroom. Standardized testing (hereafter "testing") is when some organization or person writes and administers a single test for everyone. In the early 20th century (when Dewey was in his heyday), psychologists wanted a way to figure out how to measure a person's IQ. (Really, according to Leon Kamin in The Science and Politics of IQ, these psychologists really just wanted to give the government a way to sort soldiers out in the run-up to World War I). Testing became vogue, not just in terms of determining IQ and whether or not a prospective soldier was "fit" for combat, but also in terms of evaluating students' and schools' success. Fortunately, as many of the theories about IQ and a person's inherent worth were debunked as eugenicist claptrap (did I mention that the same psychologists who developed the first IQ tests were eugenicists?), the popularity of standardized testing in schools waned.

In many schools (most notably in colleges and universities), however, the teaching methods most often associated with testing (lecturing, drill-and-kill, memorization, etc) held on, even as more and more evidence mounted that these methods weren't all that effective. Starting around the middle part of the twentieth century, educational constructivism started to take hold, and as I said up until about 5 years ago, no teacher training program worth its salt could be found that didn't educate its teachers in the principles of educational construtivism, often through the work of John Dewey.

So, how did Dewey become a stand-in for educational constructivism writ large? Blame Pat Robertson. When Robertson announced his candidacy for the 1988 presidential election, he called out the evil thinkers who had damaged America's standing. These included obvious choices such as Charles Darwin, Karl Marx and Sigmud Freud, but also (bizarrely) John Dewey. Specifically, in part of his educational plan, Robertson stated, "We will insure to [students] a return to a basic broad based phonics approach to reading. Our children must learn basic language and basic math. They must know the facts of history --the facts of geography -- the facts of science. The "progressive education" advocated by John Dewey and his followers is a colossal failure and must be abandoned."

In many ways, the anti-Dewey, pro-"facts are out there" position has been a key plank of the Republican educational platform ever since Robertson's statement. It's no wonder, then, that George W. Bush's brainchild, NCLB, would call for a return to testing, which is really a turn away from educational constructivism.