Eternal Sunshine

In the 2004 film Eternal Sunshine of the Spotless Mind, Kate Winslet's character Clementine decides to shed her memories of a former boyfriend Joel (Jim Carrey) "on a lark." She hands over all of her possessions that have a link to their romance to a company that specializes in erasing memories. When her ex-boyfriend seeks out Clementine the next day to try to make up, Joel finds out that she has no knowledge of who he is. Joel also opts to have his mind wiped of all memory of Clementine, too. He hands over all the items he believes have something to do with his relationship with her.

Eventually, Joel realizes that his memories of Clementine are being erased in reverse order. As he experiences in his mind the earlier, happier times with her, he realizes that he wants to stop the procedure and keep the memories. He decides he wants to remember Clementine. The rest of the movie is a comedic struggle between Joel to keep his memories, and the technicians at the company to continue with the procedure. In the end, Clementine and Joel decide to keep their memories and get back together.

All of this seemed like wonderfully impossible science fiction until last year, when researchers at the SUNY Downstate Medical Center in Brooklyn, New York, figured out how to delete memories in rodents. The researchers initially taught the rats to negotiate a chamber that shocked their feet if they chose the wrong path. Then, after the rats had learned the right path to take, their brains were injected with a drug called ZIP, which caused the rats to quickly forget their hard-earned knowledge regarding safe routes through the chamber.

It's a tough life -- that of a laboratory rat's.

It turns out that the science behind Eternal Sunshine isn't too far from reality. The brain stores negative emotional memories very differently from unemotional, or even positive ones. Negative emotional memories, for instance, tend to capture more details about the experience than positive ones. While most memories are kept only in one area of the brain, the brain uses two separate parts to capture particularly traumatic memories.

One of those areas is the hippocampus, the normal seat of memory, where all other memories are kept. The other area is the amygdala, one of the brain's emotional centers. This explains the "negative haunches" and "bad vibes" we sometimes feel about people or events even when we have no memory associated with them. It also explains why people who are incapable of forming long-term memories can nonetheless form subconscious memories of traumatic events.

Obviously, the possibility that we will someday soon be able to scrub the brain of bad memories raises ethical questions. And, predictably, an internecine battle will arise within the bioethics community. On one side, naysayers will warn about sinister government campaigns to control the masses. On the other side, idealists will promise an end to post-traumatic stress disorder and Alzheimer’s. But the reality is that both will miss the big picture, and memory deletion will probably be most used for reasons like the one in Eternal Sunshine.

Most people fear new technology until the neighbor down the street starts using it, at which point it becomes a commodity rather than a horror. Contraception, in-vitro fertilization, antidepressants, the Internet, Facebook have all followed this track. Most present-day uses of these technologies are consensual and matter-of-fact, and memory deletion will probably be no different.

I don't doubt that memory deletion could be used to erase truly traumatic memories. We could erase memories such as those one might form while fighting in a war. It seems unethical to condemn people who have experienced terrible trauma to suffer when we have the means to eliminate that suffering. But would this treatment contribute toward the "dehumanization" of soldiers? Acts committed within the context of war are often quite horrendous, and it's that knowledge that deters us from going to war for frivolous reasons. Perhaps a better alternative would be a world in which these acts rarely or never happened at all rather than one in which they are simply accepted as necessary.

The desire for people not to suffer is not a bad thing, but it must be balanced by the need to learn from our experiences. This applies to traumatic experiences as well as our own awareness of unpleasant thoughts. What if everyone, everywhere suddenly "forgot" about their own mortality? There would be no impetus to live responsibly or to enjoy every moment. Neither would there be motivation to find cures for cancers and other diseases, since nobody would have any concept in the first place that they might die. Whether the aim is to treat a war-battled psyche or a broken heart, an ethical drug therapy should alleviate suffering, but not to the point where the we cease to care about what we experience.