Four Ways Your Discrete Trial Is All Tied Up!


by Brohavior

Ogden Lindsley was a graduate of B. F. Skinner and had a knack for mixing things up.  The first human free-operant lab was at Metropolitan State Hospital in Waltham, MA, set up by Lindsley from a grant to Skinner by NIMH in the mid-50s.  During his professional career he became a strong proponent of behavioral fluency and a technology of process known as Precision Teaching. 

Lindsley defined Precision Teaching as an educational process in which decisions concerning educational interventions are based “on changes [observed] in continuous self-monitored performance frequencies displayed on ‘standard celeration charts’” (Lindsley, 1992, p. 51).  As such, one of the more beautiful, yet subtle, components of Precision Teaching is it’s reliance on free operants. 

A free operant is contrasted with a discrete operant in that discrete operants include teacher delivery of trials in which the opportunity for the student to respond is restricted to parameters primarily controlled by the teacher. The free operant, on the other hand, holds no such restrictions—hence its freedom.

Lindsley (1996) described four ways that teachers could free-up trials to more adequately accommodate for the fundamental datum of behavior analysis and Precision Teaching – rate of response (count/unit of time).  Lindsley called these the Four Free Operant Freedoms:

  1. The Freedom to Present Stimuli – Teach the learner how to present trials to themselves at their own pace.
  2. The Freedom to Repeat Responses – Create your instructional materials such that your student can practice again and again.
  3. The Freedom to Form Responses – Design your materials to allow for enough flexibility such that the learner can select a comfortable response form – one that is correct, but doesn’t lead to boredom or fatigue easily.
  4. The Freedom to Speed Responses – Create your instructional materials and measurement systems to allow the student to perform the response forms as many times as possible within a specified timing period (10 seconds, 30 seconds, 1 minute, 1 day, etc.).

Lindsley (1996) assures his readers that these four freedoms are “crucial to developing and maintaining fluent performances.” (pg. 202).  Have you had experience with the four freedoms or Precision Teaching?  Let us know in the comments below!  Also be sure to subscribe to bSci21 via email subscription to receive new articles directly to your inbox!


Lindsley, O. R. (1992). Precision teaching: Discoveries and effects. Journal of Applied Behavior Analysis, 25, 51-57.

Lindsley, O. R. (1996). The Four Free Operant Freedoms. The Behavior Analyst. 19, 199-210.

About the Author:

brohaviorFollowing graduation from Master’s programs many behavior analysts find themselves in a cold dark world where they are searching for the light of peers that share their approach to the subject matter of behavior. One online group called Brohavior (derived from “brotherhood”) has recently created a refuge for behavior analysts looking for the light in order to continue their own development. The group aims to create a collaborative environment where students of behavior analysis are exposed to and pursue behavior analytic literature, philosophy and research that is outside of the scope of the BACB-approved course sequence.

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