So, imagine the pig has a heavy collar and to reward the pig for walking forward you might remove the heavy collar.

所以，想象这头猪带着很重的项圈,作为对这头猪向前走的奖励,你可以把项圈拿掉。

耶鲁公开课 - 心理学导论课程节选

So, you reinforce the pig for walking forward and you punish the pig for walking backward.

那你就对这头猪向前走的行为给予强化,如果它向后退，你就惩罚它。

耶鲁公开课 - 心理学导论课程节选