The Crier

Love Potion No. 9

Someday, love potions may be possible. Until then, stick with Yeats

Eugene Morrow · The Empiricist · Mar 22, 2007

A young woman sits in the Arb listening to her boyfriend recite Yeats. Her palms are sweaty, her heart is racing. It’s springtime in Ann Arbor, and she’s in love.

The sweat on her palms and the feeling in her heart aren’t exactly the same, but you can bet they’re related. Scientists separate emotions into two distinct parts: states and feelings. States are the physical part — perspiration, heartbeat, dilated pupils. But those butterflies in her stomach? That’s a feeling.

Emotional states are obviously controlled by your brain. They’re a direct response to emotional stimuli in your environment: a stimulating scent, a violent movie, or a tearful goodbye. Your amygdala — two small balls of neurons at the base of the brain — controls most of these responses, especially fear.

The amygdala coordinates emotional states in response to your environment in a few ways. First, it stores basic emotional information. Nothing quite so complex as “Beauty is power; a smile is its sword,” but enough for your brain to know that when you see your lover’s smile, you ought to be smiling too.

Shock a mouse at the same time you play a tone and the mouse will learn to fear the tone.

Next, your amygdala receives basic sensory information. Based on this sensory information, and its stored emotional information, your amygdala mediates the proper physiological response (like sweating palms or a furrowed brow). It does this implicitly: no processing is needed, per se. Remember the old telephone-switchboard operators? If the inputs are your senses, and the outputs physiological responses to emotion, then the switchboard is your amygdala.

Most of these connections are pre-made. Fire is linked with fear, smiling with happiness, death with sadness. Newer, more complex connections are made when different, unconnected stimuli accompany connected stimuli. Shock a mouse at the same time you play a tone and the mouse will learn to fear the tone. Ring a bell before you feed a dog and the dog will salivate not just for the food, but the bell itself (remember Pavlov?). This is fine for emotional states, but what about emotional feelings?

Allow me to introduce you to the switchboard operator: your neocortex (colloquially referred to as the “seat of consciousness”). Your neocortex is about the most advanced structure in your brain. Whenever your amygdala directs an emotional response, it also tells the neocortex what’s going on. In fact, when the amygdala is stimulated electrically, test subjects often report feelings of fear and anxiety when surrounded by emotionally neutral objects. So the amygdala “talks” to the neocortex. And it seems the neocortex talks back.

Love potions may be possible someday, but only when we know enough about conscious experience.

The neocortex is connected with many parts of the brain, including the amygdala. These connections are reciprocal, and therefore allow the cortex and amygdala to hold a kind of conversation. Your neocortex, while receiving information from your amygdala, is also privy to all your sensory information. So while physiological-emotional responses don’t require the neocortex, they can be influenced by it.

Your neocortex can “correct” your amygdala. It can identify the shadow you mistook for a bear as being just a shadow after all. It can also tell your amygdala to create new, more complex emotional connections: Pollock and pleasure, Frege and fear, Schindler and sadness. This is how emotional memories are formed. Your amygdala tells your cortex you’re afraid, and at the same time your eyes tell your cortex you’re looking at a flashing light. The next time you see that flashing light, you’re likely to be afraid of it.

But if emotions are just the result of interplay between brain centers, does that mean we could artificially create emotions by getting the right neurons to fire? Maybe, but that’s easier said than done. Humans have all kinds of mood altering chemicals at our disposal, from Selective Serotonin Reuptake Inhibitors (i.e. Prozac) to Psilocybin (e.g. Magic Mushrooms). But so far all we can do is affect the activity of neurons in certain regions of the brain.

By playing with specific neurotransmitters, we can change which neurons fire when. But in order to elicit specific, complex emotional responses to individual objects, we need to be able to alter neuronal firing patterns with greater accuracy. Moreover, our understanding of emotions and their processing is predicated mainly on an understanding of fear — and even that isn’t as complete as we’d like. Love potions may be possible someday, but only when we know enough about conscious experience, and synthetic biochemistry, to make them. Until then, stick with Yeats.