We can distinguish between two kind of operational definitions, experimental and measured (Kerlinger, 1973). Experimental operational definitions explain the meaning of independent variables; these definitions define exactly what was done to create the various treatment conditions of the experiment. An experimental operational definition includes all the steps that were followed to set up each value of the independent variable. Schachter gave experimental operational definitions of high and low anxiety. The high-anxiety condition was defined in terms of the electronic equipment set up in the room, the ominous behaviour of Dr. Zilstein, and the explicit statement that the subjects should expect painful shocks. The low-anxiety condition was defined by the absence of equipment, Dr. Zilstein’s more relaxed manner, and the explicit statement that the shocks would not be painful. If we were to replicate Schachter’s experiment, we would be able to follow all these procedures in setting up each of the two treatment conditions. Note that if Schachter had merely said, “I set up a high-anxiety condition and low-anxiety condition,” we would not know how to go about repeating his experiment. We would also have difficulty interpreting his findings because we would have no way of judging just how “anxiety producing” his conditions may have been.