Take the question of whether we are the only species to care about the well-being of others. It is well known that apes in the wild offer spontaneous assistance to each other, defending against leopards, say, or consoling distressed companions with tender embraces. But for decades, these observations were ignored, and more attention was paid to experiments according to which the apes were entirely selfish. They had been tested with an apparatus to see if one chimpanzee was willing to push food toward another. But perhaps the apes failed to understand the apparatus. When we instead used a simple choice between tokens they could exchange for food—one kind of token rewarded only the chooser, the other kind rewarded both apes—lo and behold, they preferred outcomes that rewarded both of them.
The one historical constant in my field is that each time a claim of human uniqueness bites the dust, other claims quickly take its place. Meanwhile, science keeps chipping away at the wall that separates us from the other animals. We have moved from viewing animals as instinct-driven stimulus-response machines to seeing them as sophisticated decision makers.
— The Brains of the Animal Kingdom, The Wall Street Journal.