The idea of people scared to death is nothing new. At the turn of the 20th century, Sir Arthur Conan Doyle wrote "The Hound of the Baskervilles." In this mystery, Sherlock Holmes investigates the case of a man who had a heart attack seemingly caused by fear of a ghostly dog haunting the area. The man, Charles Baskerville, was particularly susceptible to the stress of the deadly dog because of his heart condition. Doyle was also a practicing physician, and a century after the tale's publication, researchers from the University of California at San Diego set out to see how much of his real-life work might have informed his fiction.
To examine what they termed the "Baskerville effect," or dying of a heart attack brought on by intense psychological stress, the researchers examined death certificates to see if a cultural fear brought on death. In Chinese and Japanese cultures, the number four has extremely unlucky connotations, because the pronunciation of it is so similar to the word for "death." Even in the United States, some Chinese and Japanese people try to avoid travel on the fourth of each month; you might occasionally see a menu without fours or a building without a fourth floor.
Researchers hypothesized that if Chinese and Japanese people were unnerved by the date, then there could be a spike in cardiac-related deaths on that day caused by stress. They examined the death certificates of about 200,000 Chinese and Japanese people over a period of 25 years, with a control group of 47 million white people [source: Phillips, et al.].
The researchers found that Chinese and Japanese mortality was indeed higher on the fourth of the month as compared to the white control group. For the Chinese and Japanese group, there were 13 percent more cardiac deaths than expected on the fourth of each month, and the numbers only went up in California, where large populations of those ethnic groups are located, indicating that more people are raised with a cultural fear of four [source: Phillips et al.]. The researchers examined nine alternatives that might explain why deaths would be higher on the fourth, including a superstitious person avoiding hospitalization on that day, but they found no compelling links.
The study of the Baskerville effect is significant because it represents one of the few ethically responsible ways to conduct research on being scared to death; it isn't, after all, appealing to sign up for a study in which researchers will present you with your worst fear only to see if you're still standing afterward. But this study primarily considered people with existing cardiac conditions; what of those who walk around perfectly healthy? Could a scary encounter send them 6 feet under? Go to the next page to find out.