||Philosophy 203: Scientific Reasoning
Quiz: The General Pattern of Scientific Research
Directions: In the passage below, identify the major steps in the pattern of scientific research and describe them in the spaces below.
"One by one, infectious diseases that once ravaged society and preyed especially on children have been quelled by better sanitation, antibiotics, and vaccinations...
A growing number of scientists now suspect that stamping out (of) ... innocuous organisms (as well) is weakening some parts of children's immune systems, allowing other parts to grow unchecked. Such an imbalance, they theorize, triggers a host of illnesses, including asthma, allergies, and even such autoimmune diseases as rheumatoid arthritis and the most server type of diabetes.
This notion, called the hygiene hypothesis, arose from scientists' inability to explain the rising prevalence of asthma and allergies in many developed nations ...
Pollution and allergens--such as mold and pollen--can take some of the blame, but not all of it. "One needs an explanation" for these trends, says Graham A.W. Rook of the University College London Medical School, who is one of the chief advocates of the hygiene hypothesis...
Swiss researchers reported that hay fever was less common for farm children than for urban children or for rural children who didn't live on farms. Several years ago, scientists found that children in large families--particularly the younger siblings of brother--had fewer allergies than children in small families. Researchers speculated that exposure to the germs brought home by older siblings protected the younger children from allergies.
According to the hygiene hypothesis, the immune system (has two responses). One arm....deploys specialized white blood cells, called Th1 lymphocytes (to) direct an assault on infected cells throughout the body. (The) other arm...produces antibodies that block dangerous microbes from invading the body's cells...(these are called) Th2 lymphocytes. The Th2 system also happens to drive allergic responses... According to the hygiene hypothesis, The Th1 system can grow stonger...through fighting infections or through encounters with certain harmless microbes. Without such stimulation...the Th2 system flourishes and the immune system teeters toward allergic responses.
...Bolstering that idea, a study in the ...Lancet found that children from small families who entered day care before age 1 were less likely to develop allergies than those who entered day care earlier.
...Some researchers are already trying to create vaccines that mimic potentially crucial immune effects of the microbes that society has banished.
...Encouraged by the epidemiological studies that support the hygiene hypothesis, some investigators are now trying to prevent illness by pumping up the Th1 system artificially ... A team ... is conducting human trials of a Th1-inducing vaccine to counter asthma."
Adapted from Siri Carpenter, "Modern Hygiene's Dirty Tricks," Science News, Vol. 154, 108.