In concurrent schedules of reinforcement [a mouse has a choice between pressing a button to get sugar or pressing it to get cheese], the choice or preference between the two alternative response is calculated by the relative rate of response and is represented by the quotient: Ra ___ Ra + Rb Where Ra and Rb represent the rate of response in option a and option b, respectively. [I guess they mean option a is pressing the sugar and b is the cheese] ~~~~~~ Does this make sense to anyone? I don't understand why you divide those things into each other or what sort of use the answer you get could possibly be. Let's say he presses the button for sugar 5 times and for cheese twice 5/(5 + 2) =0.7 Ok now he presses the button for sugar twice and for cheese 5 times. 2/(2+5) =0.1 What the goose use is that to anyone!? Is there something missing? Should it say something like "anything over .5 means a is preferred and anything under .5 means b is preffered? Would that make sense? Maybe it's just so obvious they can't be bothered to mention it . I translated this, here's the original, in case i messed up: Volviendo a los programas concurrentes, la elección o preferencia entre las alternativas de respuesta se calcula por la tasa relativa de respuesta y se representa por el cociente: Donde Ra y Rb representan, respectivamente, la tasa de respuesta en la alternativa a y la tasa de respuesta en la alternativa b.