An experiment is reported in which variation was made of number of magazine training trials perceding barpress training in a discrete-trial situation. Some support was observed for the prediction that less rather than more response vigor would occur early in extinction for the group with the most extended magazine training (12 days), but the failure of an overtraining extinction effect (OEE) to occur limits the generalizability of these results. The hypothesis upon which the prediction is based, that an affective factor declines with extended training, is contrasted with the more familiar frustration-disruption account of the OEE, from which the obtained results are not readily predictable. The data also provide evidence for a frustration-vigor effect (FVE) but only with regard to the referent (barpress) response itself, and the implications of this result are discussed.