Drive and reward in an acquired-fear paradigm

Either five minutes or 48 hours following classical fear conditioning (CS paired with inescapable shock) four groups of rats were trained to jump a hurdle from the conditioning box into an adjoining box. During hurdle jumping one-half of the Ss in each delay condition had the CS present in both boxes, while for the remaining Ss it was absent (NCS). CS Ss performed better than NCSSs (p less than or equal to .005) and five-minute Ss performed better than 48-hour Ss (p less than or equal to .001). The results suggest (a) that there is a need for a drive concept in behavior theory, (b) that drive and reward combine additively, and (c) that there is a loss over 48 hours of fear conditioned to apparatus cues, but not of fear conditioned to the CS.