Punishment in the goldfish as a function of electrode orientation

For each response to a nipple from which they were trained to take liquid food, goldfish were punished with a brief ac shock administered through a pair of stainless steel electrodes placed either to the right and left of the animal, over and under it, or in front and back of it. As anticipated, on the assumption that the aversiveness of shock is a function of the potential difference across the animal's body, the right-left orientation of the electrodes was found to produce the least suppression of feeding and the front-back orientation the most.