Seven surprising truths about the world: a lot of the bad news you think you know is wrong.

• Author: Bailey, Ronald
• Position: Cancer rates; pornography and rape; life expectancy and population growth; IQ tests; international trade and job creation; increasing biodiversity; markets and human social interaction

DID YOU KNOW that the incidence of cancer in the United States has been declining for nearly 20 years? That the spread of pornography correlates with a decline in rape? That average IQs are going up substantially all around the world? These are just some of the truths that are well-known to the scholars who study those subjects but generally come as a surprise to even the best-educated among us.

As reason reflects on how the world has changed since the magazine's founding in May 1968, here are seven surprising pieces of unalloyed good news.

Cancer Rates Are Going Down

A 2007 American Cancer Society poll found that seven out of 10 Americans believed that the risk of dying from cancer is going up. In fact, not only have cancer death rates been declining steeply, age-adjusted cancer incidence rates have been falling for nearly two decades. That is, in nearly any age group, fewer Americans are actually coming down with cancer.

Advances in modern medicine have increased the five-year survival rates of cancer patients from fro percent in the 1970s to 68 percent today. That much you might expect. More surprising is that the incidence of cancer has been falling about 0.6 percent per year since 1994. That may not sound like much, but as John Seffrin, CEO of the American Cancer Society, explains, "in recent years, about 100,000 people each year who would have died had cancer rates not declined are living to celebrate another birthday."

Why is cancer becoming more rare? Largely because fewer Americans are smoking, more are having colonos-copies in which polyps that might become cancerous are removed, and many women stopped hormone replacement therapy in the early 2000s, all behaviors that prevent the onset of cancer. Advances in genetic screening for cancer risks will further reduce cancer incidence as empowered patients take preventive actions like actress Angelina-Jolie's double mastectomy, which reduced her lifetime risk of heritable breast cancer from around 90 percent to 5 percent.

The news is not all good. Rising levels of obesity have been associated with increases in cancers of the kidneys, esophagus, pancreas, and elsewhere. But falling mortality and incidence rates do indicate real progress in the War on Cancer.

More Porn, Less Rape

Over the past two decades, as pornography has become much more easily accessible over the Internet, the rate of rape and sexual assault has declined by about 60 percent, according to the Department of Justice's Bureau of Justice Statistics (BJS).

The BJS conducts an annual National Crime Victimization survey of more than 100,000 households, asking if anyone has been the victim of various crimes in the past year. In 1995, the rape/sexual assault rate was reported as 5 per 1,000 American women over age 12. In 2011, the rate had fallen to 1.8 rapes/sexual assaults per 1,000.

Meanwhile access to pornography has dramatically increased. "It is a truth universally acknowledged, that a person in possession of a fast Internet connection must be in want of some porn," the journalist Sebastian Anthony joked last year on the website Extremetech. Dozens of porn platforms are among the top 500 sites in terms of traffic, according to Google's Doubleclick Ad Planner. The largest, Xvideos, draws 4.4 billion page views per month--three times more than CNN or ESPN, and twice as many as Reddit.

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A comprehensive 2009 review in the journal Aggression and Violent Behavior by the Texas A&M International University psychologist Christopher Ferguson and the University of Texas at San Antonio criminologist Richard Hartley concluded that easy access to porn does not cause rape. "Considered together, the available data about pornography consumption and rape rates in the United States seem to rule out a causal relationship," Ferguson and Hartley wrote in their summary of the academic literature. "One could even argue that the available research and self-reported and official statistics might provide evidence for the reverse effect; the increasing availability of pornography appears to be associated with a decline in rape."

The Clemson economist Todd Kendall, in a 2006 study supported by the National Bureau of Economic Research, concluded that "Internet access appears to be a substitute for rape; in particular, the results suggest that a IO percentage point increase in internet access is associated with a decline in reported rape victimization of around 7.3 percent." Kendall found that "there is no statistically significant relationship between internet access and any individual FBI index crime (other than rape), including murder, robbery, aggravated assault, robbery, larceny, and auto theft." Crime rates are plummeting all over, but it's only rape that appears to be pegged to online connectivity.

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