yaba? that's thai for methamphetamine tablets. no. heroin, do you want heroin? no. his voice back to normal. i can take you to a cock fight, you can gamble. i'll pass. just a little bitter traited now, so, what do you want? those little peppers, i want tom tom -- some good, spicy dinner. my driver, not surprisingly, is kiss appointed, and -- disappointed, and i'm left wondering aside from various shades of illegality, what do all his offers have in common? what is it exactly that makes a vice? now, there are lots of ways to approach this question of what makes a vice. you can approach it with cultural anthropology or social history, and these are valid and useful endeavors. but i'm a biologist, so what i'm looking for is a more cross-cultural, biological explanation, something a little blunter but perhaps more fundamental. and the key observation here is that we all have in our brains an anatomically and biochemically-defined pleasure circuit. we call it the medial fore brain pleasure circuit, medial just means it's in the middle of your brain, and fore brain means