John Cleverley and D. C. Phillips place Locke's "Some Thoughts Concerning Education" at the beginning of a tradition of educational theory which they label "environmentalism". In the years following the publication of Locke's work, Etienne Bonnot de Condillac and Claude Adrien Helvétius eagerly adopted the idea that people's minds were shaped through their experiences and thus through their education. Systems of teaching children through their senses proliferated throughout Europe. In Switzerland, Johann Heinrich Pestalozzi, relying on Locke's theories, developed the concept of the "object lesson." These lessons focused pupils' attention on a particular thing and encouraged them to use all of their senses to explore it and urged them to use precise words to describe it. Used throughout Europe and America during the eighteenth and nineteenth centuries, these object lessons, according to one of their practitioners "if well-managed, cultivate Sense-Perception, or Observation, accustom children to express their thoughts in words, increase their available stock of words and of ideas, and by thus storing material for thinking, also prepare the way for more difficult and advanced study."