This week’s podcast is about selective outrage — why we get so upset over some things, and then not over others. It’s called “Which Came First, the Chicken or the Avocado?” (You can subscribe to the podcast at iTunes, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.)

We start with Marius the giraffe. Marius lived at a zoo in Copenhagen. Zoo officials said he was a “surplus” animal: too genetically similar to other giraffes, and therefore he couldn’t breed. It was kinder, they said, to kill him. So they fed him some rye bread (“his favorite food”), shot him in the head, and dissected him in front of a crowd of onlookers, including kids. Next they fed his corpse to the lions. Perhaps not surprisingly, the world reacted with outrage.

How did this compare to the outrage expressed over the killing of more than 146,000 people during the ongoing civil war in Syria? Not quite commensurate. Ammiel Hirsch, senior rabbi at the Stephen Wise Free Synagogue in New York, noticed this disparity, and he talks about it with Stephen Dubner:

HIRSCH: If you recall there was saturation coverage of a Danish zoo that killed a giraffe in front of dozens of schoolchildren and fed it to the lions. And it struck me that that received so much attention and so much publicity — not that I’m in favor of killing giraffes, in general, or killing any animals, let alone in front of children — but it was at the time when there was such savagery around the word, and in particular, hundreds of people in that week were butchered in Syria, and there was such little coverage about that event, and so much coverage about the killing of one giraffe that it simply struck me that that probably says something about how we think and about the nature of our society.

Steve Levitt says that outrage over Marius’s death, and the increased level of compassion people have for animals, is overall a positive sign for society:

LEVITT: I think being nice to animals is a luxury good. I remember when I first went to China 14 years ago to adopt my daughter and we went to an open-air market. And the animals they had to eat and the circumstances of these animals were just, to a Westerner, outrageous… And then when I went back about five years later, to the same open-air market, what just amazed me is that suddenly they had a big section of the open-air market that was devoted to fish tanks. In just five years, China had boomed in wealth. [They went] from literally eating anything they could find, to deciding it was fun to have animals for pets.

You will also hear from Wall Street Journal reporter Jose de Cordoba, whose article about the Mexican avocado trade perhaps should have outraged people but didn’t. De Cordoba explains how most avocados eaten in the U.S. are “blood avocados,” made to pass through a criminal cartel that extorts, kidnaps, and kills.

And finally, big thanks to listener Rebecca Pearce. She wrote to us with a question that gets Levitt and Dubner wondering what’s more valuable: the life of a polar bear or the life of an economist.

Addendum: We made a mistake in this episode when we said Marius the giraffe was killed in front of a group of people. He was dissected in front of a crowd, but euthanized in private. We regret the error.