the difference between drinking from 7 by sja20118


									                                 by industry professionals to track movie in-          explains this effect as the result of a “substitu-          swamped in the short run (the evening and
                                 formation. They also used,           tion of foregone activities.” In other words,               night after the movie). DellaVigna explains,
                                 a website that rates movies on a ten point            even though violent individuals are no longer               “You’ve got two opposing effects. You have a
                                 scale along three axes—sex/nudity, violence/          fixed on the edges of their seats, they have                movie like Hannibal causing more aggression,
                                 gore, and profanity—to separate movies into           initiated a less raucous evening and may just               but it’s also taking people out of bars. It’s the
                                 strongly violent (Wanted), mildly violent (The        go to bed after a late movie. And even if they              second effect that dominates.”
                                 Incredible Hulk), or non-violent (Wall-E).            do go out after the film, they simply have less                  DellaVigna is quick to caution against
                                 These were combined with crime data from              time to drink themselves to belligerence. “It’s             jumping to political conclusions. Like the
                                 the National Incident Based Reporting Sys-            the difference between drinking from 7 pm to                laboratory studies, this study cannot com-
                                 tem to study the correlation between violent          1 am and drinking from 11 pm to 1 am,” says                 ment on the long-term effects of media vio-
                                 crime levels and attendance at violent films.         DellaVigna.                                                 lence. A better take-home message from the

                                                                                                                                                                                                       BRIEFS Wine country salmon
                                      DellaVigna and Dahl found that for every               These findings may appear to dispute                  study is that any policy addressing a particu-
                                 one million theater attendees, violent crime—         evidence from other research that does imply                lar activity must address the next best activity
                                 defined as reported assaults and intimida-            a relationship between media violence and                   as well. Perhaps violent video games increase
                                 tion—decreases by 1.1 percent for mildly              crime. Indeed, laboratory studies in psychol-               aggression, but they also keep a potential
                                 violent films and 1.3 percent for strongly vio-       ogy have shown an increase in aggressiveness                offender fixed in his seat. Happily incapaci-
                                 lent films between 6 pm and midnight. The             in individuals upon viewing violent video                   tated, the young ne’er-do-well foregoes his
                                 effect per million viewers between midnight           clips, although these studies don’t address                 next favorite activity, which could be cow tip-
                                 and 6 am (well after the theaters close) was          actual violent crime. Other studies show that               ping, or worse. “Can we think of activities for
                                 larger: a decrease of 1.9 percent and 2.1 per-        survey respondents who view violent media                   youth that are more attractive than commit-
                                 cent for mildly and strongly violent movies,          are more likely to be involved in self-reported             ting crimes?” asks DellaVigna. “That’s some-
                                 respectively. This equates to about 1,000 few-        violent crime, although the direction of cau-               thing we should keep in mind when design-
                                 er occurrences per weeken, and an estimated           sation in these studies is unclear. DellaVigna              ing policies on entertainment.”
                                 $695 million saved per year in avoided costs          himself found evidence supporting the claim
                                 associated with violent crime. No statistically       that an increase in violent behavior does fol-
                                 significant effect was observed for attendance        low exposure to violent films relative to ex-               Paul Crider is a graduate student in physical
                                 at nonviolent movies.                                 posure to nonviolent films; the effect was just             chemistry.
                                      Ideally, a scientist interested in the effects
                                 of movie violence might randomly assign
                                 half of a random group of people to watch
                                 a violent film and the other half to watch a
                                 nonviolent one and then observe what hap-
                                 pens. The randomness of the groups averages
                                 out other possible explanations for any dif-
Image courtesy of Tim Crawford

                                 ferences in observed behavior. “In the movie
                                 theater, we’re not randomized. We choose to
                                 watch violent movies,” explains DellaVigna.
                                 This makes analysis more difficult, and other
                                 possible influences on the data were consid-
                                 ered and corrected for, like occasions of high
                                 television viewership (think Superbowl), pos-
                                 sible seasonal effects, and inclement weather.
                                      To explain the counterintuitive results,          Land use changes, like the transition from forests to housing developments, threaten wine country salmon.
                                 DellaVigna developed a model in which
                                 consumers choose between attending a vio-
                                 lent movie, attending a nonviolent movie,             Swimming                                                    Department of Environmental Science, Policy
                                 or doing some alternative social activity. The                                                                    and Management at UC Berkeley, is trying to
                                 model, once fit to the data, suggested that           Upstream                                                    predict how continued development near
                                 violence-prone individuals are dispropor-                                                                         the Russian River in Sonoma County will de-
                                 tionately attracted to violent films, and while       Wine country salmon struggle                                grade native salmon habitat. Merenlender’s
                                 in the theater, they are “voluntarily incapaci-       for survival                                                lab recently developed a statistical model that
                                 tated.” That is, they’re watching a movie and                                                                     uses patterns of land use and stream quality
                                 eating popcorn instead of engaging in other           The classic California meal of salmon and                   from the past ten years to predict how habitat
                                 activities associated with violent behavior,          Chardonnay may also come with a side of                     degradation will continue. Sonoma is an ideal
                                 such as drinking at a bar.                            irony. The recent rise of vineyards and coun-               place for this research because, as Meren-
                                      That violent crime decreased even more           try homes in Sonoma County may be con-                      lender explains, “there are lots of immediate
                                 during the late night hours, after theaters are       tributing to the decline in population of the               pressures on the environment there.”
                                 empty, was a more curious result. DellaVigna          pink-fleshed fish. Adina Merenlender, of the                     According to Merenlender, water man-

                                                                                                                                              access to sewer and water service, and, most
                                                                                                                                              importantly, quality of salmon habitat associ-
                                                                                                                                              ated with a given piece of land. They used
                                                                                                                                              all this information and more to predict the
                                                                                                                                              likelihood that a given parcel’s land use will
                                                                                                                                              change salmon habitat quality in the future.
                                                                                                                                                    Using their model, the researchers pre-
                                                                                                                                              dicted that in ten years rural-residential de-
                                                                                                                                              velopments and vineyards will cover more
                                                                                                                                              than ten times as much land as urban areas.
                                                                                                                                              To boot, the model predicts rural-residential
BRIEFS Wine country salmon

                                                                                                                                              developments and vineyards are more likely
                                                                                                                                              to occur in places where good-quality salmon
                                                                                                                                              habitat remains. Merenlender says of vineyard

                                                                                                                                                                                                Image courtesy Bill Mitchell
                                                                                                                                              and rural-residential land owners, it’s “not
                                                                                                                                              just the flowpaths on their property, but the
                                                                                                                                              cumulative effect also.” Those cumulative im-
                                                                                                                                              pacts are precisely what the forecast indicates
                                                                                                                                              are the biggest threat to salmon habitat.
                             Salmon species native to the Russian River in California’s wine country are running out of breath as they swim         Merenlender’s model is especially useful
                             upstream to spawn. Sedimentation from vineyards is depleting the river’s oxygen.                                 because it incorporates land value. It identi-
                                                                                                                                              fies parcels that, if conserved, would most
                             agement and the number and size of build-                tographs, they categorized land use into three          cost-effectively preserve salmon habitat. Me-
                             ings, collectively known as the “development             types: urban, rural-residential, and vineyard.          renlender explains that habitat conservation
                             footprint,” have the greatest influence on the           The researchers classified a piece of land as           groups can help salmon the most by invest-
                             habitat quality of nearby streams. Develop-              “urban” if it had at least one building per acre        ing in “places that aren’t completely degraded
                             ment footprint includes structures, roads,               and as “rural-residential” if a single building         but are likely to become degraded.”
                             and other areas where the ground surface is              occupied between one and forty acres. A                       To curtail the expansion of rural resi-
                             packed so hard that it is no longer perme-               piece of land was categorized as “vineyard”             dences and vineyards, Merenlender suggests
                             able to rainfall. The water aggregates and the           if at least ten percent of its area was covered         a shift in supply and demand. She suggests
                             runoff becomes like a fire hose, accelerating            by grape vines.                                         that planners consider the environmental
                             flow and increasing sediment deposition into                   They discovered that all three land use           impacts of expanding vineyards and resi-
                             nearby streams. “The big issue that most do              types are associated with degraded spawn-               dences, and that people who invest in them
                             not appreciate,” Merenlender explains of                 ing habitat. Per unit area, urban develop-              consider those impacts as well. Simply put,
                             vineyards and other types of development, “is            ment casts the most ominous shadow. But                 she says, “You have to get everyone to reduce
                             the rerouting of water that causes fast moving           that’s old news––scientists proved long ago             their footprint. What you want to do is pull
                             water can cause excessive erosion.” That ex-             that dense urban development leads to poor              everybody in.” Creating incentives for high-
                             cessive erosion eventually accumulates in the            habitat quality for sensitive fish like salmon.         density development, she says, is essential
                             spaces between river stones where salmon lay             What’s novel about this research is that it             to saving salmon habitat. Perhaps one day
                             their eggs, depriving the eggs of oxygen. As a           identifies a strong correlation between poor            soon, people will envision the ideal develop-
                             result, adult salmon have difficulty produc-             quality salmon habitat and the abundance of             ment as a place where they can walk around
                             ing abundant and healthy offspring.                      nearby rural-residential developments and               their neighborhood, shop, and stop into a
                                  Before predicting how land use will                 vineyards.                                              restaurant to enjoy their wine and salmon—
                             change salmon habitat quality over the next                    The researchers used this strong rela-            without the irony.
                             ten years, researchers first had to quantify             tionship, in conjunction with the mountain
                             how land use is affecting salmon habitat                 of existing evidence about imposing urban
                             quality in Sonoma today. Merenlender and                 developments, to forecast how changes in                Liza Ray is a staff member in integrative
                             her team, including the lead author and for-             land use over the next ten years will affect            biology.
                             mer postdoctoral fellow Kathleen Lohse, and              salmon habitat quality. Unlike suburban
                             former graduate student David Newburn,                   sprawl, rural-residential development does              Want to know more? Check out:
                             used habitat quality and land use data to                not grow adjacent to the urban center. In-    
                             establish this relationship. Field crews from            stead, it’s prone to “leap frog” all over a re-         php?I=546
                             the California Department of Fish and Game               gion, and like a leaping frog, it is difficult
                             collected habitat quality data from 922 sites            to predict. The researchers in Merenlender’s            and
                             in streams and rivers of Sonoma County. The              group built a statistical model that included
                             UC Berkeley scientists gathered land use data            past growth patterns, regional plans, zoning  
                             available from existing county tax assessor              laws, proximity of lands to major employ-               details.asp?people_id=684
                             records. From those records and aerial pho-              ment centers, availability for development,


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