Author Archives: Katie Wilkinson

Fun Activity to Teach Correlation vs. Causation

One of the common arguments that anti-vaxxers use to support their cause is that as vaccination rates have increased so have autism diagnoses. People will even trot out pretty graphs showing a steep increase in autism rates following the introduction of the MMR vaccine. There is no medical evidence that vaccinations lead to autism as I discussed in a previous post. Making the leap from correlation to causation is fairly common, even among science majors, though. One of the first activities I do in my Neurophysiology class is a Correlation vs. Causation assignment (full activity: NeuroscienceSociety1_CorrelationVSCausation_2). I have students describe what conclusions they can draw from the graph below. I then have them design an experiment that would actually test whether organic food sales/consumption causes autism.

AutismOrganicFood

http://imgur.com/1WZ6h
This activity is a good way to review things like independent and dependent variables, controlled experimental design, and to challenge them to come up with reasons why two things may be correlated. I also challenged the students to find news articles that improperly conflated correlation with causation and they came up with some doozies. For instance, people who have more sex make more money and kids who eat lots of candy are more likely to be jailed for violent offenses. No discussion of bad science would be complete without a mention of everyone’s favorite ‘Dr.’, Dr. Oz. He had a woman on his show claiming that carrying your cell phone in your bra could lead to breast cancer since she had developed a tumor at the exact location where she carried her cell phone. Some other fun correlations (that were reported as such) included decreased highway fatalities with increasing Mexican lemon imports and increased margarine in the house with increased divorce rates. My absolute favorite correlation (reported in a New England Journal of Medicine study with a proposed, although not directly tested mechanism) was that increasing chocolate consumption correlates with the number of Nobel Prize winners per capita. So, skip those late nights in the lab and eat more chocolate (or not if you learned something about correlation)!

Science in the State of the Union Address

Two major science themes were emphasized in tonight’s State of the Union: a call to action on climate change and the announcement of a new Precision Medicine Initiative (relevant excerpts from the speech shown below).

In my favorite part of the whole speech Obama chastised those who have used the ‘I’m not a scientist’ line to preface a denial of climate change: Well, I’m not a scientist either. But you know what? I know a lot of really good scientists at NASA and at NOAA and at our major universities, and the best scientists in the world are all telling us that our activities are changing the climate…” Obama highlighted his administration’s action on climate change including the recent agreement with China to decrease emissions, but didn’t offer specifics on any additional climate change policies.

Obama also announced a new Precision Medicine Initiative to try to harness the advances in genetic sequencing to specifically target treatments to subgroups of patients. One of the guests at the State of the Union was a cystic fibrosis patient that benefited from the drug Kalydeco, which treats the ~5% of cystic fibrosis patients with specific mutations in the CFTR protein. It remains to be seen how this initiative will be structured and whether it comes with increased funding for medical research.

Climate Change

“And no challenge, no challenge, poses a greater threat to future generations than climate change.

2014 was the planet’s warmest year on record.

Now, one year doesn’t make a trend, but this does: 14 of the 15 warmest years on record have all fallen in the first 15 years of this century.

I’ve heard some folks try to dodge the evidence by saying they’re not scientists, that we don’t have enough information to act. Well, I’m not a scientist either. But you know what? I know a lot of really good scientists at NASA and at NOAA and at our major universities, and the best scientists in the world are all telling us that our activities are changing the climate, and if we don’t act forcefully, we’ll continue to see rising oceans, longer, hotter heat waves, dangerous droughts and floods, and massive disruptions that can trigger greater migration and conflict and hunger around the globe. The Pentagon says that climate change poses immediate risks to our national security. We should act like it.

That’s why, over the past six years, we’ve done more than ever to combat climate change, from the way we produce energy, to the way we use it. That’s why we’ve set aside more public lands and waters than any administration in history. And that’s why I will not let this Congress endanger the health of our children by turning back the clock on our efforts. I am determined to make sure American leadership drives international action.

In Beijing, we made a historic announcement: the United States will double the pace at which we cut carbon pollution, and China committed, for the first time, to limiting their emissions. And because the world’s two largest economies came together, other nations are now stepping up, and offering hope that, this year, the world will finally reach an agreement to protect the one planet we’ve got.”

Precision Medicine Initiative

“21st century businesses will rely on American science and technology, research and development. I want the country that eliminated polio and mapped the human genome to lead a new era of medicine: one that delivers the right treatment at the right time.

In some patients with cystic fibrosis, this approach has reversed a disease once thought unstoppable. Tonight, I’m launching a new Precision Medicine Initiative to bring us closer to curing diseases like cancer and diabetes and to give all of us access to the personalized information we need to keep ourselves and our families healthier.”

Full transcript of the State of the Union speech can be found here.

Talk to Your Friends and Family About Science: Vaccines Edition

The number of people who have contracted measles from an outbreak started in Disneyland has topped 50 this week, making it a very good time to talk to your friends and family about the importance of vaccination. Vaccines are one of the most successful public health advances, practically eliminating such awful diseases as polio and smallpox. Since 2000, vaccines have been credited with decreasing the number of worldwide childhood deaths by 3.6 million, even though the population has increased by 1 billion in the same time frame. Sadly, the success of vaccination may be contributing to the current outbreaks of diseases, like the measles, that we thought were a thing of the past. Without the memory of closed public pools and rows of iron lungs in hospital wards it is easier to weigh the perceived risks of vaccination as the scarier option. Below are ways you can answer some common questions about vaccination as well as some resources about the safety and efficacy of vaccination.

 Is a Measles Outbreak Really That Bad?

Short answer: YES! In 1980, before widespread vaccination 2.6 million people died of the measles. In 2012, with 84% of babies vaccinated that number was only 122,000 worldwide. About 1 or 2 in 1,000 babies who contract the measles will die, whereas the worst vaccine side effect, a severe allergic reaction, only occurs in 1 in 1,000,000 babies. The measles are one of the most contagious diseases known. Measles spread through the air and an unvaccinated person can still contract the disease if they enter the room 2 hours after the infected person has left. The Ro, or average number of people one sick person will infect, for measles is 18! For comparison, the Ro for Ebola is 2. This is why it is important to quarantine unvaccinated people potentially exposed to the measles. A measles outbreak is also incredibly costly, with contact tracing and other measures costing ~$33,000 per person infected.

 Shouldn’t It Be My Choice Whether To Vaccinate My Children?

Many of the health decisions that we make, like what foods we eat, are choices that mainly affect us as individuals. The choice to refuse vaccination, though, affects society at large since the success of vaccines rests on herd immunity. Transmission of a disease can be prevented if the majority of people are immune. Herd immunity protects those who cannot be vaccinated because they are too young or have a compromised immune system that prevents them from being vaccinated. Herd immunity also protects the minority of people vaccinated that don’t gain protection (most vaccines are ~80-85% effective, which is pretty darn good, and the measles vaccine is ~95-98% effective.). As long as between 83-94% of the population is vaccinated, it is highly unlikely that a disease will spread. US vaccination rates are now ~91% on average, lower than half the countries in the world, and even lower in certain areas, including Marin County, CA where only 83% of kindergartners were vaccinated in 2010. If only a few families opt out of vaccinations, they still receive protection from herd immunity. Once too many people opt out, the rest of us are placed in danger, just like the 2 babies too young for vaccination that contracted the measles at Disneyland. It is in society’s best interest to start making the cost of refusing to vaccinate higher, especially since the safety of vaccination has been shown repeatedly (serious side effects from vaccines are very rare). For instance, unvaccinated children are barred from entering many daycare facilities and we could make it much harder to receive vaccination exemptions for children in public schools. Similarly some pediatricians are refusing to treat unvaccinated children, which will protect their other patients.

But Don’t Vaccines Cause Autism?

No, vaccines do not cause autism. This idea was started thanks to a fradulent, now retracted paper by Andrew Wakefield (who has since had his medical license revoked). Since the publication of that paper, many studies including over 14.7 MILLION children have found NO LINK between autism and vaccination. Anti-vaxxers will trot out figures showing increasing autism rates as vaccination rates have increased. Don’t fall for this, that is simply correlation, not causation. In fact, there is a similarly good correlation between autism rates and organic foods sales, which I’m sure we can all agree is a highly unlikely cause of autism.

AutismOrganicFood

 

http://imgur.com/1WZ6h

Some Great Resources About Vaccines

Wonderful cartoon by the Nib explaining how vaccines work, how shady the Wakefield study was, and how important vaccinations are.

Upworthy infographic sponsored by the Bill and Melinda Gates Foundation showing the evidence that vaccines do not cause autism.

Business Insider video explaining herd immunity and why ‘If you don’t vaccinate your kid, please don’t ask me not to judge you.’

Skeptical Raptor’s explanation of the mumps outbreak in the NHL and why vaccinated players can still get the mumps.

Journal article for clinicians refuting 3 common anti-vaxx arguments (behind a paywall).

 * *Updated on 2/8/15 to include risk of death from measles vs risk of severe allergic reaction to MMR vaccine, efficacy rate of MMR vaccine, and clarification that I am in no way suggesting the sale of organic food causes autism.**

Advocacy Webinar for Early Career Scientists

Are you interested in advocacy but not sure where to start? Join the Society for Neuroscience (SfN) for “Becoming an Early Career Advocate” on January 9, 2015 at 11:00 a.m. (2 p.m. EDT) to hear from members of the 2014 class of Early Career Policy Fellows (including me) about how they became effective science advocates. Listen as they share their successes over the past year and learn about activities you can implement in your own institution or SfN chapter. Finally, find out how to apply for the 2015 class of Early Career Policy Fellows. If you register for the webinar you can ask questions in real time. A recording of the webinar will be posted for those that can’t attend on Jan 9. Even if you are not a neuroscientist, you can still get some ideas about how to advocate for science.

The Science of Eyewitness Testimony: An Example of How to Incorporate Current Events and Science Policy Into Your Classroom

One of the reasons to invest in scientific research is to gather evidence that can inform policy so that our government can act more effectively, efficiently, and fairly. Of course, for that to happen we need informed citizens to pressure their politicians to enact reforms.  According to the AAAS Vision and Change report one of the core competencies that all undergraduate biology students should have is the ability to understand the relationship between science and society. To help students practice this competency, I have been trying to incorporate more discussions about how findings in neuroscience can be used to understand and hopefully help solve societal problems.  Of the 40ish students that take my Neurophysiology class every year, likely only a handful of them will need to directly use the knowledge they gain about the ionic basis of action potentials. I hope the rest of them will take away from the class the ability to discriminate correlation from causation, how to find good sources of information, and what a well designed experiment looks like.  This year’s events in Ferguson have highlighted issues that could be used to start discussions in many different classes, but below I have a suggestion for an activity that could be used in a Neuroscience or Psychology course.

Neuroscience & Society Activity: Why were there conflicting eyewitness accounts of the shooting of Michael Brown?

One of the biggest news stories of the year was the shooting of an unarmed black teenager, Michael Brown, by a white police officer in Ferguson, Missouri. Eyewitnesses reported that Brown had his hands raised signifying surrender when he was shot. This led to sustained protests following the shooting and the decision by a grand jury not to indict the police officer. The prosecutor released the evidence seen by the grand jury, including the testimony of all eyewitnesses and the police officer. Even though all 22 witnesses viewed the same event, not all eyewitnesses agreed about whether Brown was kneeling or his hands were up during the final shots (a nice summary of statements can be found here).

Seeing something with your own eyes is considered the best proof that it happened and eyewitness testimony can be quite persuasive. Memories are not unchangeable video recordings, though. They can be influenced by your past experiences and emotions as well as by what you hear from others, including police officers when they are taking your statement, your friends, and/or the media. In fact, the Innocence Project reports that 72% of convictions overturned by DNA evidence involved inaccurate eyewitness testimony.

I have designed an activity (full assignment and suggested readings and video can be found here: NeuroscienceSociety_Eyewitness Testimony) to explore whether the science of memory and perception supports our faith in eyewitness testimony or whether it can explain the disparity between witness statements in the Brown case. All students will read a short blog post and watch a TED talk by psychologist Elizabeth Loftus that discuss how memories can be subject to manipulation. Groups of students will be assigned additional readings that they will summarize for the rest of the class. This activity could be easily tailored depending on the goals and level of your students. For instance, you could assign readings that discuss molecular mechanisms of memory formation, readings on implicit biases, or even conduct your own experiment about the fallibility of memory (see this example experiment suitable for K-12 classrooms). Below are the discussion questions I plan to ask students to complete before we discuss their answers in class.

Discussion Questions:

 1)       In your own words describe how multiple people could give such differing accounts of the shooting of Michael Brown.

2)      What are some ways that memories can be altered?

3)      Many people, including Michael Brown’s family, have advocated for the use of body cameras by police. What are at least 3 pros and 3 cons of requiring all police officers to wear body cameras?

4)      From what you have read/seen, what procedures would you suggest for law enforcement to use when collecting eyewitness statements?

5)      What was one thing you were surprised by or learned from this assignment?