Scientists, on the other hand, are often very skeptical of work that appears in the scientific literature. They treat most papers as tentative results that need to be confirmed. The most obvious flawed papers will be refuted by further work, as in the recent arsenic in DNA paper or earlier work on cold fusion. Usually, flawed papers will just be ignored and they will die a quiet death.
Not all scientists agree when healthy skepticism is appropriate. The junk DNA controversy is a good example of when scientists differ in their evaluations of the difference between good science and bad science. Proponents of junk DNA are skeptical about papers claiming that most DNA has a function even though the science in the paper seems sound. Opponents of junk DNA, on the other hand, treat such papers as real data and they are skeptical of papers that support junk DNA.
The point is not that individual scientists are always appropriately skeptical. The point is that science as a way of knowing works collectively and in the long run healthy skepticism is crucial to advancing knowledge.
How do you explain healthy skepticism to students? It's relatively easy to assign a paper to undergraduates and have them write up a summary for subsequent discussion. Sometimes you pick a paper that you know is probably wrong but it's extremely rare that the students will recognize this on their own. You can explain why you are suspicious and skeptical but what it really boils down to is experience. Mature scientists just have a "instinct" for what's right and what's not. I think it depends on whether the conclusions differ from your current model of how things should work. (Different scientists have different models.)
Experience can't be taught. That's one of the reasons why I'm a bit skeptical about having undergraduates delve into the primary literature.
Here's an example of a paper I just read (Ahola et al., 2012). There doesn't seem to be anything wrong with the science but I just don't believe the suggestion is true. I can't really tell you why. What do the rest of you think? Should scientists be skeptical of this work?
Work-Related Exhaustion and Telomere Length: A Population-Based Study
Psychological stress is suggested to accelerate the rate of biological aging. We investigated whether work-related exhaustion, an indicator of prolonged work stress, is associated with accelerated biological aging, as indicated by shorter leukocyte telomeres, that is, the DNA-protein complexes that cap chromosomal ends in cells.
We used data from a representative sample of the Finnish working-age population, the Health 2000 Study. Our sample consisted of 2911 men and women aged 30–64. Work-related exhaustion was assessed using the Maslach Burnout Inventory - General Survey. We determined relative leukocyte telomere length using a quantitative real-time polymerase chain reaction (PCR) -based method.
After adjustment for age and sex, individuals with severe exhaustion had leukocyte telomeres on average 0.043 relative units shorter (standard error of the mean 0.016) than those with no exhaustion (p = 0.009). The association between exhaustion and relative telomere length remained significant after additional adjustment for marital and socioeconomic status, smoking, body mass index, and morbidities (adjusted difference 0.044 relative units, standard error of the mean 0.017, p = 0.008).
These data suggest that work-related exhaustion is related to the acceleration of the rate of biological aging. This hypothesis awaits confirmation in a prospective study measuring changes in relative telomere length over time.
[Hat Tip: Mike the Mad Biologist]
Ahola, K., Sirén, I., Kivimäki, M., Ripatti, S., Aromaa, A., et al. (2012) Work-Related Exhaustion and Telomere Length: A Population-Based Study. PLoS ONE 7(7): e40186. [doi:10.1371/journal.pone.0040186]