The experiment investigated the effect of manipulating time of detention on nonreward trials in 2 sizes of goal box on the frustration effect (FE). A double-runway apparatus was employed. The variables under investigation were manipulated in the 1st goal box (G1) and the effects of the experimental conditions were observed in Runway 2 in terms of starting, running, and goal-entry times. Magnitude of the FE was greater following 3 or 15 sec. detention than following 90 sec. detention on nonreward trials. During both pretest and test trials, the effects of G1 size and of detention differ greatly depending on the response measure employed, starting and running times showing quite different pictures.