Williams, D.C., Hayashi, Y., Brewer, A., Saunders, K.J., Fowler, S. and Pitts, R.C. 2019. Transitions from Rich-to-Lean Schedules Increase Attack in a Laboratory Model of Social Aggression in Pigeons: I. Fixed-Ratio Schedules. Mexican Journal of Behavior Analysis. 45, 2 (Dec. 2019). DOI:https://doi.org/10.5514/rmac.v45.i2.75580.