but clever us and clever other chrisers. we've figured out how to -- chrisers, we've figured out how to activate it artificially. we didn't evolve to take a tobacco plant and set it on fire in our mouth andinhale the fumes, but it turns out the nicotine can activate the pleasure circuit. as can alcohol and cannabis and heroin and cocaine and am fete mean. some of these drugs work directly on the dopamine signaling mechanism. other ones work indirectly through more complicated electrochemical cascades. but they all have a property in mob, that they increase dopamine in the pleasure circuit and make your feel pleasure. you might think, well, that was a long list of drugs. i get it. any psychoactive drug is going to turn on your brain's pleasure circuit. but it turns out that actually isn't true. so drugs like mescaline and lsd, ssri antidepressants, antihistamines, these are all drugs that are psychoactive that don't activate the pleasure circuit. so some do and some don't. and it turns out, we'll return to the topic of addict