n 1999 a postdoc in my lab, Karim Nader, walked into my office with an idea for a new experiment. He outlined his plan to test a controversial theory in neuroscience called memory reconsolidation that contradicted what we had learned as a field about how memories were stored. The experiment he proposed seemed like such a reach that I told him not to bother doing it. As luck would have it, Nader wasn't a particularly obedient postdoc.
A month later, Nader came back into my office and said, "It worked." I looked at him surprised. "What worked?" I asked. "The reconsolidation experiment," he told me. I was amazed. Most neuroscientists, myself included, believed that a new memory, once consolidated into long-term storage, is stable. It's as if every long-term memory had its own connections in the brain. Each time you retrieve the memory, or remembered, you retrieved ...