That's going to presumably be given--mathematically if we gave it a number, we'd slap a zero on that.

如果用数学解释,给它一个数字，给它一个零。

耶鲁公开课 - 死亡课程节选

It only works within species. So, in another experiment they put a rabbit in the other room and the chimpanzee would slap the lever repeatedly to make the rabbit scream in pain and jump.

这种结果只出现在同种动物上，在另一个实验里,他们在另一个房间放一只兔子,结果黑猩猩不停地拍杠杆,让兔子痛得上跳下窜，大声尖叫。

耶鲁公开课 - 心理学导论课程节选