In the old model, dopamine is released when an animal gets a food reward. But in this new model, dog essentially looks back and reflects and its brain tags the sound with dopamine as a cause of the food reward. John Defterios: This matters a lot to neuroscientists who spend their careers thinking about this. It still hasn't quite settled, I would say, in the world of neuroscience. He says researchers are already exploring it.
The response to the death of the 29-year-old has differed from that of previous cases of police killings; we ask what the tragedy indicates about how America deals with police violence. Our correspondent says a lawmaker’s murder in Afghanistan highlights the misery of women under the Taliban. And why a decades-old model of animal and human learning is under fire.
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