Dopamine is an artistic and occasionally overreaching study of the causation of love -- namely, whether it's something profound and intangible, or whether it's just chemical impulse. Mark Decena's film never figures out the answer, but it leaves one with the sense that a useful discussion has been tapped. It's not that Rand, the computer programmer played with quiet understatement by John Livingston, is incapable of romanticism; it's that he's been conditioned to note his physical reactions upon feeling attraction (the adrenaline bursts from the smell of perfume, for instance). As a clear line of demarcation from the scientist, Sabrina Lloyd is the free-spirited teacher who paints on canvas rather than on a computer screen and considers love strictly mental and emotional. Add in Koy Koy the computerized pet as a stand-in for the closed-off programmer, and Dopamine has some fairly obvious metaphors and methodology. But it's effective because it uses these symbols to provoke thought in the audience, even if that thought doesn't coalesce into clear conclusions. (How could it, when the topic is so fertile?) Digging at the heart of the dichotomy are the chemistry-themed voice-overs from Rand's father, a husband dealing with his wife's Alzheimer's, who has retreated to his dispassionate explanation of love out of bitterness. Because it exists on this intellectual and sometimes remote level, Dopamine should please the scientists in the audience a bit more than the romantics.