Biology Now, 2e

A Critical Choice ■ 27

1998. The Lancet is a well-known peer- reviewed

medical journal and therefore a reputable source.

The paper was unremarkably titled “Ileal-

Lymphoid-Nodular Hyperplasia, Non-specific

Colitis, and Pervasive Developmental Disorder

in Children.” It was a study of 12 children rang-

ing in age from 3 to 10 years old who had expe-

rienced a loss of language skills—a symptom of

autism spectrum disorders—as well as diarrhea

and abdominal pain. Parents of 8 of the 12 chil-

dren said the onset of symptoms occurred shortly

after the child’s immunization with the measles,

mumps, and rubella (MMR) vaccine.

The authors of the paper, a team of 12

researchers, concluded that more research was

needed to study a possible relation between the

observed brain dysfunction, bowel problems, and

the MMR vaccine. In a press conference when

the paper was published, one of the authors, a

British doctor named Andrew Wakefield, stated

that he believed single vaccines, rather than the

MMR triple vaccine, were likely to be “safer”

for children. The study and press conference

sparked widespread fear among parents that the

MMR vaccine could cause autism.

The study was published around the same time

that officials began documenting an increase in

rates of autism. Since the early 1970s, when orga-

nizations started counting the number of people

with autism for the first time, the incidence of

autism has increased 20- to 30-fold in the United

States and other countries. In 2002, the estimate

was that one in 150 children aged eight years (the

age of peak prevalence) had the disorder. In 2004,

that number had risen to one in 125. In 2006, one

in 110. By the year 2012, the most recent year with

available data, an estimated one in every 68 eight-

year-olds had an autism spectrum disorder. The

CDC has said that the rise in rates is likely due

to heightened disease awareness, more screening

Increasing confidence of scientific claims

Increasingly challenging to read

Social media Secondary literature Primary literature

Figure 2.5

Scientific claims in the media and literature

It is easy to find and read scientific claims in social media. However, this is not a good source of

scientific information. For help in making important life choices, it is important to go to the secondary

literature or even the primary scientific literature for accurate and reliable information.

Q1: Why are we less confident of scientific claims made over social media?

Q2: Where would you place a blog in this figure? Would it matter whether or not it was written

by a practicing scientist? Explain your reasoning.

Q3: Give an example of when you would rely on secondary literature to evaluate a scientific

claim and an example of when you would go to the primary literature. What is the basis of that

decision?