Science Searches for the Truth
How do we know what is true? This is a fundamental question in science.
Some items are simply facts (things that are verifiable, that we all agree on). However, many claims in science are not facts but rather explanations, and these must be supported with evidence.
For example, the statement that polar bears live only in the arctic is a fact based on extensive observation. However, a question a scientist might ask is, why do polar bears live only in the arctic, and not also in the Antarctic—or on Mt. San Jacinto? There are many possible explanations for the fact that these bears only live in the arctic. Perhaps they used to live in other places but died out everywhere but in the arctic. Perhaps they originated in the arctic and never left. Perhaps something in their diet or physiology prevents them from living elsewhere, or perhaps they could live elsewhere and simply have not spread to other places yet. There are many possible explanations for why polar bears live only in the arctic.
How can we tell which explanation is true? This is not an easy question. The way most humans determine what is true is to let ideology guide them. That is, they have a preconceived notion of what they believe is true, which often derives from an authority or a source they trust, and they find evidence to support their beliefs (and ignore evidence to the contrary). Unfortunately, while this sort of thinking tends to make people happy, especially when they share their beliefs with a community, it is not likely to actually reveal what is true.
Some people follow a different strategy. They advocate that we look at the evidence for ourselves. This is a good idea in principle, but it has some problems too.
Aristotle (who was once considered the authority on most things) claimed that women have fewer teeth than men.
Many years later, simple observations revealed this to be incorrect. This is a case where you might look at the evidence for yourself. Now consider this image.
This is the sort of information generated by physicists, using the Large Hadron Collider. By smashing protons together, scientists can reveal the existence of the elementary particles like the Higgs boson. It is not likely most of us can interpret the four muons shown in the image, which provided evidence for the elusive Higgs boson. There are many areas of science (perhaps most area) where it is not really possible for most of us to consider the evidence directly for ourselves. We just don’t have the background knowledge to make sense of the evidence.o what do we do?
We listen to experts! Ultimately, we simply have to trust experts. But, we can still apply critical thinking. First, we have to determine who is actually an expert. Many people claim expertise, but are not truly experts. Then we have to consider if there are any indicators of bias or conflicts of interest. We can try to determine if an expert represents a view that is widely accepted (a consensus) or is an outlier. Finally, even when listening to experts, we have to stay relentlessly vigilant, demand that they back up their claims with evidence. Science does not rely on expertise or authority except as much as people who have these traits are likely the best people to show us with the best evidence. And, of course, we ourselves have to remain as unbiased as possible too.Both at the same time! Not easy. To be clear, experts may well be trusted sources, but science, unlike many human institutions, is very egalitarian and does not respect authority alone. Rather, we expect even the best experts to show their work. We trust them to marshal and present evidence, not simply to tell us to believe them because they are an expert.
As we explore life in our biology class, I hope you have become a more critical consumer of information—both more skeptical and more open-minded. What follows is an exploration of a few important aspects of being scientifically literate.
Causation vs. Mere Correlation
If you want to know the truth, you have to be able to determine what the cause of various events or phenomena are. To do this means you have to be able to distinguish causation from association for other reasons (which we also call correlation).
Popular interpretations of science often get this issue wrong. Consider this graph: (GRAPH IS UPLOADED ON FILES)
1. What conclusions can you draw from this graph? I am not asking you to speculate on the meaning of the graph. Rather, the question is, what does this graph actually tell us?
2.Here is a rare example of math humor. Explain how this comic is humorous?
Scientists often remind people that, “correlation is not causation”! However, correlation is not without value in science. Often correlations point to where more research is worthwhile. In fact, there are several broad types of evidence in science, including association (correlation) and causation.
Hard evidence of causation is a precious commodity in science, and there is only one type of research that gives us solid evidence of causes. This type of research involves a study design known as a randomized controlled trial (RCT). It is the gold standard for research because it can show a causal connection.
RCTs are set up to be double-blind if possible. This means neither the subjects nor the researchers know who is getting which intervention until after the experiment is over. This reduces bias. RCTs typically have a control group, and a big enough sample to be statistically valid as well.
RCTs also have some drawbacks. They are often very expensive to do, so they usually have small sample sizes. Another issue is that they often not very generalizable. This means that, for example, if you did an RCT testing an herb for lowering blood sugar in male diabetics, you cannot be certain from your results if the herb would also cause lower blood sugar in female diabetics too. If you study Americans, you cannot generalize your results to Italian people. If you study animals, which is commonly done, you cannot assume the results hold for people.
Finally, as far as evidence for what is true, we never take a single study, even a well done RCT that definitively shows causation, as the final word. We need strong evidence that is repeatable. To adequately support an explanation or claim in science, we need:
Direct evidence (from RCTs if possible)
A plausible mechanism that makes sense
Associations that support the causal relationship (from observation studies or from case reports)
Multiple studies (replication), along with multiple lines of evidence
So, for example, you may read a claim that a certain food reduces or increases the risk of a particular disease. Should you accept that claim? If the claim is well supported, it should have:
RCTs showing a measurable effect of the food on the disease
Observational studies showing correlation of consumption of the food with lowered risk of the disease in question
A reasonable biochemical mechanism by which the food might work to reduce the disease
Studies with animals, cell cultures, or even computer simulations, confirming a plausible connection between the food and the effect.
Only then, will scientists accept the claim as true.
Flag question: Spacer
Does the Headline Accurately Describe the Research?
Now try your hand at interpreting studies.
Read the following descriptions of research. Assume the studies were peer reviewed and published in a journal. So assume good scientific practices in all of these studies. You do not need to critique the studies themselves–you only need to determine if the headline accurately describes the research.
Keep in mind that headlines are by nature short and attention-grabbing. So a headline that does not including all the details of the research is not necessarily inaccurate. Headlines may be accurate without being exhaustive or complete. For example a small study of olive oil consumption in Greece that showed a reduction in cancer risk might say: “Olive oil reduces cancer risk”. The fact that this claim comes from one small study of a particular group of people in Greece are not inaccuracies of the headline. The details would presumably be given in the article.
Do you think that the headlines below accurately describe the research?
Es_Estefanyyy
2 hours ago
3. Here is a study:
Participants were a group of 42 teenagers 12-17 years old who played an average of 26 hours of violent video games per week. They were compared to another group of 35 teenagers also 12-17 years old who played non-violent video games for a similar amount of time each week. All participants were males living in Florida.
The subjects were followed for 2 years.
The violent video game group was found to have had 64% more arrests or disciplinary actions at school for violent behavior than the non-violent video game group.
Here is a headline from a news story about the study:
New study reveals playing violent video games leads to violent behavior in teenagers
Does the headline accurately describe the research?
Explain why or why not
How could you reword the headline to be accurate if you do not think it is accurate?
4.Here is a study:
Diet data spanning 20 years was collected from a group of over 100,000 people in China. Subjects had reported their diet twice monthly for the entire period.
Medical records cataloged cardiovascular events over the study period.
The people who ate the most broccoli had the lowest incidence of cardiovascular disease.
People who ate the least broccoli had the highest incidence of cardiovascular disease.
Overall the high broccoli consumption group had 88% fewer cardiac events (heart attacks) than the lowest broccoli consumption group.
Here is a headline from a news story about the study:
Broccoli consumption significantly reduces the risk of cardiovascular disease
Does the headline accurately describe the research?
Explain why or why not.
How could you reword the headline to be accurate if you do not think it is accurate?
5.Here is a study:
A total of 82 people in Massachusetts with mild to moderate cardiovascular disease were randomized into a control or experimental group.
The experimental group was given broccoli sprout extract capsules daily for 1 year. The control group received a placebo.
The broccoli extract group had 38% fewer cardiovascular events (heart attacks) and 23% fewer deaths than the placebo group after 1 year.
Here is a headline from a news story about the study:
Broccoli sprout extract reduces cardiovascular mortality in people with cardiovascular disease
Does the headline accurately describe the research?
Explain why or why not.
How could you reword the headline to be accurate if you do not think it is accurate?3. Here is a study:
Es_Estefanyyy
2 hours ago
A Strategy
What people need most when confronted with a claim that may or may not be true is a strategy to assess reliability of the source. Michael Caulfield of Washington State University has developed what he calls “four moves”. These are:
Check for previous work: Look around to see if someone else has already fact-checked the claim or provided a synthesis of research.
Go upstream to the source: Go “upstream” to the source of the claim. Most web content is not original. Get to the original source to understand the trustworthiness of the information.
Read laterally: Read laterally. Once you get to the source of a claim, read what other people say about the source (publication, author, etc.). The truth is in the network.
Circle back: If you get lost, hit dead ends, or find yourself going down an increasingly confusing rabbit hole, back up and start over knowing what you know now. You’re likely to take a more informed path with different search terms and better decisions.
In general, you can try these moves in sequence. If you find success at any stage, your work might be done.
When you encounter a claim you want to check, your first move might be to see if sites like Politifact, or Snopes, or even Wikipedia have researched the claim (Check for previous work).
If you can’t find previous work on the claim, start by trying to trace the claim to the source. If the claim is about research, try to find the journal it appeared in. If the claim is about an event, try to find the news publication in which it was originally reported (Go upstream).
Maybe you get lucky and the source is something known to be reputable, such as the journal Science or the newspaper The New York Times. Again, if so, you can stop there. If not, you’re going to need to read laterally, finding out more about this source you’ve ended up at and asking whether it is trustworthy (Read laterally).
And if at any point you fail–if the source you find is not trustworthy, complex questions emerge, or the claim turns out to have multiple sub-claims–then you circle back, and start a new process. Rewrite the claim. Try a new search of fact-checking sites, or find an alternate source
Es_Estefanyyy
2 hours ago
6. Here is an interesting issue on which to apply the four moves.
Many websites and other sources claim that simple carbohydrates (carbs) are digested faster than complex carbs, which make you feel full longer as they are digested more slowly.
Find a source that claims simple carbs are digested more quickly than complex, and assess its reliability.
[Extra credit if you actually find evidence this claim about carb digestion is true.]
Wikipedia is usually among the top results of an online search. You most likely use Wikipedia.
Wikipedia has this to say about Wikipedia:
Wikipedia is a multilingual online encyclopedia, based on open collaboration through a wiki-based content editing system. It is the largest and most popular general reference work on the World Wide Web, and is one of the most popular websites ranked by Alexa as of June 2019. It features exclusively free content and no commercial ads, and is owned and supported by the Wikimedia Foundation, a non-profit organization funded primarily through donations.
Wikipedia was launched on January 15, 2001, by Jimmy Wales and Larry Sanger. Initially an English-language encyclopedia, versions in other languages were quickly developed. With 5,903,725 articles, the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias. Overall, Wikipedia comprises more than 40 million articles in 301 different languages and by February 2014 it had reached 18 billion page views and nearly 500 million unique visitors per month.
Is Wikipedia a reliable source? Is it good quality source, whether or not it is reliable?
Let’s consider an article on Wikipedia relevant to biology and look at how reliable it really is.
Imagine you had to write a paper on endosymbiotic theory.
You will not be writing a paper on endosymbiotic theory! Rather you will be evaluating sources of the sort you would use if you had to write a paper on this subject.
7.Investigate what endosymbiotic theory claims about the origin of eukaryotic cells, like our own. Your textbook mentions endosymbiosis and there is lots of information elsewhere as well.
Use any source except the Wikipedia article.
Describe the claims of endosymbiotic theory.
8.Go to the Wikipedia article on Endosymbiotic theory https://en.wikipedia.org/wiki/Symbiogenesis
and evaluate it critically.
With any source, there are at least two considerations:
Is the source good quality (i.e., is it likely to be correct)?
Is the source academically appropriate? (i.e., has indicators of scholarly reliability, so that you could cite it in a paper you wrote in college)
A source that is academically appropriate is very likely (but not absolutely certain) to be good quality. However, this does not necessarily go the other way. For example, a blog by a world-class expert in a topic is probably great quality, but is not academically appropriate.
Discuss the quality and reliability of the Wikipedia article. Do you see any positive aspects? Do you see any flaws? Your response should be about 250 words
9.Find an alternative high quality, reliable source that provides a college-level overview of endosymbiosis.
Give the URL of the source and an explanation of why you think it would be a better source for a college paper than the Wikipedia article.
