为什么会觉得处理过的污水还是脏?

DAVID GREENE, host: Oklahoma is only one of several states experiencing drought conditions. Water is being recycled in many places for use in parks and gardens. But there's one type of water reuse that is still hard for people to accept. NPR's Alix Spiegel explains.

ALIX SPIEGEL: Brent Haddad is a professor of environmental studies who researches water in a place where water is often in short supply. He works in California - UC Santa Cruz.

Dr. BRENT HADDAD (Environmental Studies, University of California, Santa Cruz): There's just an issue of, well, where are we going to get the next gallon of water. New water supplies are needed.

SPIEGEL: Now, in the late '90s, Haddad started getting really interested in water reuse. At the time, a number of local water agencies in the West were proposing to build plants which would clean local waste water so that it could be reused for drinking water. But, says Haddad, these proposals were consistently shot down.

Dr. HADDAD: The public wasn't really examining the science involved. They were just saying no, and the water agencies felt that these responses were irrational. And that's what I would hear at these water agency meetings. These very frustrated water engineers saying, my public is irrational. They're irrational. They simply won't listen.

SPIEGEL: For those of you who don't know, the water reuse we're talking about is when water that's been used in your toilet or shower is cleaned through a variety of technological processes that make it so clean you can drink it. And then it's reused in the same location: to water fields, to put in reservoirs（.水库，蓄水池）, for drinking water.

Now, from the perspective of the water engineers Haddad was meeting reuse was a no-brainer. The science indicated that the water cleaned this way could be made safe. Clean Water Action, an environmental activist group, also supports reuse for drinking water, though they think that there should be national regulatory standards.

But according to Brent Haddad, no matter what the scientists or environmental organizations said, the public saw it differently. Former sewage(污水;污秽物) water was gross.

Dr. HADDAD: A scientific answer is not going to satisfy someone who's feeling revulsion(嫌恶;强烈反感). You have to approach it in a different way.

SPIEGEL: And so Haddad got funding from a noNPRofit called The WateReuse Foundation to do a study that might untangle what exactly was behind the public's revulsion. He knew just who he wanted to help him with this research. This was a job, he concluded, for psychologists.

Dr. CAROL NEMEROFF (Social and Behavioral Sciences, University of Southern Maine): I'm Carol Nemeroff. I'm trained as a psychologist.

SPIEGEL: Carol Nemeroff is a professor at the University of Southern Maine. And though she had no experience with water per se(【拉】就其本身而言), she did have experience with the issue of psychological contagion(传染；蔓延). For a living, she researches the habit we all have of thinking that once something has had contact with another thing their parts are in some way joined.

Dr. NEMEROFF: It's a very broad feature of human thinking. Everywhere we look you see contagion thinking.

SPIEGEL: Now to be clear contagion thinking isn't always negative, for example...

Dr. NEMEROFF: If I have my grandmother's ring versus an exact replica(.复制品) of my grandmother's ring, my grandmother's actual ring is better. Because she was in contact with it, she wore it's her, it's a real actual true ring. So we act like objects - their history is part of objects. And their history of contact is particularly potent.

SPIEGEL: And, says Nemeroff, there are very good reasons why people think like this.

Dr. NEMEROFF: As a basic rule of thumb for making decisions, when we're uncertain about realities in the world, this has probably served us very well.

SPIEGEL: Still, Nemeroff and Haddad wanted to figure out more about our beliefs about contagion in water. And so, together with two other psychologists, they recruited over 2,000 people and gave them a series of very fine-grained questionnaires. The questionnaires sought to break down exactly what you would have to do to wastewater, to make it acceptable to people to drink. Here's what their research found.

Dr. NEMEROFF: It is quite difficult to get the psychological, the cognitive sewage out of the water even after the real sewage is gone.

SPIEGEL: Around 60 percent of people are unwilling to drink water that has had direct contact with sewage. And Nemeroff will point out that from the perspective of a water engineer, there is a certain irony to this. After all, looked at a certain way, we are all kind of drinking water that has at one point been sewage. You know.

Dr. NEMEROFF: We are all downstream of somebody else, absolutely. And even the nice, fresh, pure spring water, you know, birds and fish poop in it. So there is no water that has not been pooped in somewhere. And I hope I didn't just freak out a whole bunch of people.

SPIEGEL: But since she knows that people are usually freaked out by this, she says you have to make a fundamental change so that people see the water differently.

Dr. NEMEROFF: You have to change the identity of it so it's not the same water. It's an identity issue not a contents issue. And so you have to break that perception. The water you're drinking has to not be the same water in your mind, as that raw sewage was going in.

SPIEGEL: The best way to do that, says Nemeroff, is to have people cognitively co-mingle the water with nature.

Dr. NEMEROFF: We had them imagine the water going into an underground aquifer(含水土层,地下蓄水层), and sitting there for either one year or 10 years. And we find that sitting in an underground aquifer for 10 years is actually helpful. It budges even those unwilling folks.

SPIEGEL: This, says Brent Haddad, is why people often find it acceptable to get their water supply from their local river, even though it once was part of the sewage of the town upstream; because they see river water as natural. But, in fact, Haddad says, putting treated water back into nature might actually make it dirty again.

Dr. HADDAD: Well, that's an interesting twist to all of this is that, in fact, when you do introduce a river or even ground water, holding water in the ground, you run the risk of deteriorating the water that's been treated. It might actually make the water quality worse.

SPIEGEL: Then reused water has to be cleaned a second time. So you see, our psychological relationship to water and our beliefs about contagion have an enormous impact on water policy in this country. We spend millions and millions of dollars. Consider what we spend on bottled water alone, for water that is cognitively free of contamination.

Alix Spiegel, NPR News, Washington.

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