There is evidence that humans are not the only animals capable of making moral decisions. As an example, the original article quotes a passage from Carl Sagan and Ann Druyan’s book Shadows of Forgotten Ancestors, describing an experiment with rhesus monkeys.
In a laboratory experiment, monkeys received food only if they voluntarily pulled a chain that electrocuted another monkey, whose distress they could see in a one-way mirror. After learning the connection, many refused to pull the chain and went hungry. In one experiment, only 13 per cent did so; 87 per cent chose to remain hungry. One monkey went almost two weeks without eating rather than hurt its companion. Monkeys that had previously been shocked were even less willing to pull the chain. The monkeys’ social rank and sex had little effect on their reluctance to harm the others.
The authors contrast the monkeys with the human experimenters who offered them this choice, and suggest that the monkeys showed a willingness to sacrifice for others, including those unrelated to them. By conventional human standards, the monkeys seemed morally exemplary and courageously resistant to doing harm.
The original article then asks whether human prisoners would behave the same way if researchers offered them the same choice. It refers to Stanley Milgram’s work on obedience to authority and observes that people can be disturbingly willing to cause pain for rewards smaller than food. Human history also honours individuals who sacrificed for others, while many people did nothing.
Reflecting on the monkeys who chose hunger rather than hurting another, Sagan and Druyan ask whether we might feel more optimistic about humanity’s future if our ethics matched theirs.
I would add that this is not a hypothetical choice for us. Each time we decide whether to eat meat, we choose whether to cause suffering to others for a reward much smaller than food was to the hungry monkeys.
Unlike the monkeys, we can satisfy hunger without pulling a chain: we can choose vegetarian or vegan food, which is in fact much healthier for us. So whenever we choose to eat meat, we choose to cause suffering and even death for the pleasure of its taste. Few forms of suffering in this world could compete with what is caused on modern farms.
Unlike the monkeys, we are not forced to watch the terrible suffering of our victims through a one-way mirror.
More answers: Vegan Ethics FAQ.