Effects of shock source and method of contact upon runway escape behavior

Rats performed better in a shock-escape apparatus with L-shaped metal strips as a runway when a constant-current (CC) shock source was used as compared to a matched impedance source. CC source superiority disappeared when the shock surface was wet (saline solution). Several additional demonstrations strongly suggest that the superiority of the CC source was not related to aversiveness per se but to responses peculiar to particular shock sources.