The project Mind-Bending Grammars examines change in mental grammars of 17th century individuals across their lifespan as attested in their writings. The project treats grammar as a self-organizing network of form-meaning schemas continuously fine-tuning itself, where activating one schema may prime formally or functionally associated ones. In analyzing multiple grammar changes in healthy adults it aspires to make a breakthrough in the cognitive modelling of grammar, and is expected to bear on views of cognitive plasticity and self-organizing systems (e.g. ecosystems). To reach these goals it will determine (i) how change in one part of an individual’s grammar relates to change in another; (ii) to what extent grammar change in individuals is possible and attested beyond childhood. This is still unsettled. Formal models hold that change occurs in language acquisition, social ones that it mainly results from adult interaction. The first ignore too much adult usage, the second grammar as a system.