would happen. But I carried out the procedure anyway, reassured by the ethically spurious but psychologically reassuring principle that it was standard practice.
The resonance with certain episodes of 20th-century history is too close for comfort, and in the next chapter I will expand on the psychological lesson I learned that day. The reason I bring up this blot on my conscience is to show what was standard practice in the treatment of animals at the time. To motivate the animals to work for food, we starved them to 80 percent of their freefeeding weight, which in a small animal means a state of gnawing hunger. In the lab next door, pigeons were shocked through beaded keychains that were fastened around the base of their wings; I saw that the chains had worn right through their skin, exposing the muscle below. In another lab, rats were shocked through safety pins that pierced the skin of their chests. In one experiment on endorphins, animals were given unavoidable shocks described in the paper as “extremely intense, just subtetanizing”—that is, just short of the point where the animal’s muscles would seize up in a state of tetanus. The callousness extended outside the testing chambers. One researcher was known to show his anger by picking up the nearest unused rat and throwing it against a wall. Another shared a cold joke with me: a photograph, printed in a scientific journal, of a rat that had learned to avoid shocks by lying on its furry back while pressing the food lever with its forepaw. The caption: “Breakfast in bed.”
I’m relieved to say that just five years later, indifference to the welfare of animals among scientists had become unthinkable, indeed illegal. Beginning in the 1980s, any use of an animal for research or teaching had to be approved by an Institutional Animal Care and Use Committee (IACUC), and any scientist will confirm that these committees are not rubber stamps. The size of cages, the amount and quality of food and veterinary care, and the opportunities for exercise and social contact are strictly regulated. Researchers and their assistants must take a training course on the ethics of animal experimentation, attend a series of panel discussions, and pass an exam. Any experiment that would subject an animal to discomfort or distress is placed in a category governed by special regulations and must be justified by its likelihood of providing “a greater benefit to science and human welfare.”
Any scientist will also confirm that attitudes among scientists themselves have changed. Recent surveys have shown that animal researchers, virtually without exception, believe that laboratory animals feel pain.240 Today a scientist who was indifferent to the welfare of laboratory animals would be treated by his or her peers with contempt.
The change in the treatment of laboratory animals is part of yet another rights revolution: the growing conviction that animals should not be subjected to unjustifiable pain, injury, and death. The revolution in animal rights is a uniquely emblematic instance of the decline of violence, and it is fitting that I end my survey of historical declines by recounting it. That is because the change has been driven purely by the ethical principle that one ought not to inflict suffering on a sentient being. Unlike the other Rights Revolutions, the movement for animal rights was not advanced by the affected parties themselves: the rats and pigeons were hardly in a position to press their case. Nor has it been a by-product of commerce, reciprocity, or any other positive-sum negotiation; the animals have nothing to offer us in exchange for our treating them more humanely. And unlike the revolution in children’s rights, it does not hold out the promise of an improvement in the makeup of its beneficiaries later in life. The recognition of animal interests was taken forward by human advocates on their behalf, who were moved by empathy, reason, and the inspiration of the other Rights Revolutions. Progress has been uneven, and certainly the animals themselves, if they could be asked, would not allow us to congratulate ourselves too heartily just yet. But the trends are real, and they are touching every aspect of our relationship with our fellow animals.
When we think of indifference to animal welfare, we tend to conjure up images of scientific laboratories and factory farms. But callousness toward animals is by no means modern. In the course of human history it has been the default.241
Killing animals to eat their flesh is a part of the human condition. Our ancestors