Barnes-Holmes, Y., Barnes-Holmes, D., Roche, B., & Smeets, P. (2001). Exemplar training and a derived transformation of function in accordance with symmetry: I. The Psychological Record, 51, 287-308.
The authors, researchers at the National University of Ireland and Leiden University, set out to determine whether exemplar training would readily facilitate the transformation of function in accordance with symmetry. Across the four experiments, 13 out of 16 subjects failed to show derived object-action (Experiments 1-3) or action-object (Experiment 4) symmetry until they received explicit symmetry training. Overall data is congruent with RFT theory.