The beginnings of ABA can be traced back to Teodoro Ayllon and Jack Michael's study "The psychiatric nurse as a behavioral engineer" (1959) that they published in the "Journal of the Experimental Analysis of Behavior" (JEAB). Ayllon and Michael were training the staff and nurses at a psychiatric hospital how to use a token economy based on the principles of operant conditioning for patients with schizophrenia and intellectual disability, which led to researchers at the University of Kansas to start the "Journal of Applied Behavior Analysis" (JABA) in 1968.