Relative Genetic and Environmental Influences Differ by Location

A fascinating new study [press release here, full text freely available here] out of the Institute of Psychiatry at King's College London shows that the relative contributions of genetic and environmental influences on various cognitive and behavioral traits differ by location. In other words, if you live in location A, trait X might mostly depend on your genetic makeup, whereas if you live in location B, trait X might be more susceptible to variation in your environment regardless of your genes. Pretty neat stuff!

The authors assessed 6,579 pairs of 12-year-old twins in the UK on 45 different characteristics. Monozygotic ("identical") twins share all of their genes and dizygotic ("fraternal") twins share, on average, half of their segregating genes. There are components of the environment that are shared by both twins and components that are unique to each twin. By using these different correlations, we are able to determine how strongly each part of the equation affects a given trait by seeing how much more similar monozygotic twins are on that trait than dizygotic twins. 

Although most researchers know better, we tend to talk about these estimates of genetic and environmental influence as if they are static and fixed. This study serves as a great reminder that this is not the case. A trait can appear more genetic or more environmental depending on the genetic makeup of the sample used or the environment the sample lives in. 

The authors focused on just one of the 45 traits that they collected for this paper: a composite of teacher-rated classroom behavior problems. I've copied a portion of their figure below. It shows the strength of the influence of the non-shared environment on classroom behavior problems. The warmer (pinker) colors represent a stronger environmental effect and the cooler (bluer) colors represent a weaker environmental effect. As you can see, there is a trend toward Londoners' classroom behavior problems being more affected by the environment than those in outlying areas. 

Figure 3a. Unique environmental influences on teacher-rated classroom behavior problems

So what is it about London that makes the environment more potent for this particular trait? The authors posited it could be income variability. In other words, London has more people who are very rich and more who are very poor, while the rest of the UK is more evenly distributed. An environment that is more variable and extreme can have more of an effect than an environment that doesn't change much from person to person. When they plotted income variability, the resulting map looks very similar to the one above. This correlation doesn't prove that income inequality itself causes classroom behavior problems. It just provides a hint about what other mediating variables to look into more closely in the future.

You can download the files and scripts to explore the rest of the rich dataset yourself here. It's free, very quick and easy, and there's even a video to show you how to manipulate the program. I played around with it a little bit tonight to check out some of the autism data. The results of my brief exploration are below.

They administered the Child Asperger Syndrome Test to the twins' parents and teachers. In addition to an overall total, the measure has subscales for social, nonsocial, and communication. There are maps for the genetic component, common environment, unique environment, and overall variation. All of that means that there are 32 maps for autism alone! That's a lot to digest. I quickly realized that I could easily get sucked down a long rabbit hole of analysis and interpretation, so I had to limit myself (for now, at least). I looked at the parent-reported social subscale and overall autism score for each component. You can see my great image manipulation skills below.

My quick maps for some of the ASD data

Both the social subscale and the overall autism score seem to follow a similar pattern to the classroom behavior problems reported in the paper: the nonshared environment is more influential in London and genetics is more influential in outlying areas. The difference is certainly more subtle for the social subscale, though. 

We already know that income variability is one factor that could potentially mediate this relationship. In general, it seems that the relative contributions of genetic and environmental influences on the development of autism differ by something that differentiates the UK's urban and rural areas. This is an exciting avenue for future research.

In addition to the important findings and implications of the data themselves, the authors are hopeful that this paper will help propel an already-developing "trend towards integrating visualization into the analytic process, instead of approaching it as a way to effectively communicate the outcome of a completed study." In other words, we scientists should take advantage of our ability to spot patterns by making various sorts of images of our data for our own exploratory purposes. Don't wait to make a pretty graphic until it's time to publish! 

In order for this to happen, we need to forge collaborations with people who specialize in this sort of thing. I'm not an expert in generating effective visualizations and I'm never going to be the best one to write the code for it, so apparently I need to start making some new friends... [edit: ew I accidentally used the wrong too before :( ]

O S P Davis, C M A Haworth, C M Lewis, & R Plomin (2012). Visual analysis of geocoded twin data puts nature and nurture on the map Molecular Psychiatry DOI: 10.1038/mp.2012.68

Teaching, Learning, and Writing! Oh, My!

I've been carrying around a set of papers for a few weeks now intending to blog about them eventually. Well, this morning I managed to spill coffee on them, and if that's not a sure sign that today's the day to actually do it and get them out of my bag I don't know what is.

This summer I attended the UW Teaching and Learning Symposium. By far the best breakout session I went to was Writing Across and Beyond the University: Innovative Writing Assignments that Foster Deep Learning in All Disciplines. I also participated in the first in a series of Writing Across the Curriculum workshops on Teaching with Writing in SBE and STEM Courses; part 1 was about Designing Writing Assignments to Help Students Learn. The main organizer of both these excellent sessions was Brad Hughes, Director of the UW Writing Center. Major props to him for consistently running efficient, engaging, informative workshops. 


Much of this entry is adapted from resources developed by Brad and others at the Writing Center. Check out their site for more innovative ideas and resources. I learned way too much to fit into one post and I don't want writing to become the main topic of my blog, so I'll stick to mostly bullet points for now. I'd be more than happy to flesh anything out in the comments if people have specific questions or interests, though!


Getting students to write is one of the best ways to promote learning in any class. (Yes, this applies to everything from engineering to music, not "just" English courses.) An abridged list of reasons why writing is effective, from writing "experts" and the brainstorming session of other brilliant grad students/ TAs/ professors/ instructors at the workshop:

• It requires deeper knowledge than multiple choice questions or other forms of assessment.
• It involves organizing and synthesizing knowledge.
• It demands explicitness.
• There's more chance for feedback (if done well...).
• It engages students with the material over a prolonged period of time.
• It slows down your thought process and concentrates your attention.
• It's hard!
• It can teach methodological practices of the discipline along with the content.
• It helps improve other forms of communication (speaking, writing) too.
• It allows for reflection and metacognition.
• It can force a new perspective.
• It can give you a chance to try on a new intellectual identity.
• It provides variety compared to other standard assignments.
• It's an active form of learning.
• It can help you discover what you don't know.

So you've decided writing is important and you want to incorporate it into your course. Now what? One of the most important things I learned from these sessions is the true diversity of writing assignment possibilities. We don't have to be bound by the standard few options! Lit review and lab report just not cutting it for your class? Here's a sampling of what else is out there:

• freewriting
• discussion points
• journal/ learning log
• microtheme
• summary/ precis/ brief
• literature review
• book/ article review
• argument/ position paper
• experimental/ lab report
• proposal/ prospectus for research
• annotated bibliography
• theory paper
• parody
• blog
• problem-based writing
• letter to the author
• course dictionary
• Wikipedia entry
• your own creative idea!

Another crucial lesson is to develop writing assignments mindfully. This will make the experience more pleasant and fruitful for everyone. A few key questions to consider:

• What is the pedagogical goal? 
• Is the assignment Writing to Learn or Writing in the Discipline? 
• What is the writer's role, who is the audience to be addressed, and what is the central task? 
• What are likely difficulties students will face and how will you address them? 
• How will the assignment be integrated into the classroom? 
• On what criteria will you evaluate the final products? 
• How will you make these criteria transparent (e.g., using a detailed rubric)?

So in sum: I want to attend every Writing Center workshop ever (part 2 of the Writing Across the Curriculum series is coming up soon!), student writing is an effective technique to promote learning in any class, there are many kinds of writing assignments possible (get creative!), and it's important to think about the assignment carefully before sending it out to your students. Happy writing!

Where have I been? Or, science outreach's place in science.

It's been a few weeks since my first post. Oops. Between home internet and computer problems, political and birthday celebrations, medical stuff, wedding planning, attempting to get in shape... you get the idea.

Oh, and, you know, doing my science. Despite popular perception, universities don't just lie dormant over the summer. In some ways, academics are actually more busy during these "breaks" because we're trying to fit in the many activities that are near-impossible during the school year. As just a sampling, I'm currently writing four manuscripts, training to code videos, getting an undergrad's project up and running, preparing for prelims, and writing a grant.

So when I read Scicurious's blog post on outreach and how "something's got to give," I found myself cheering along. She is just oh-so-right-on! Seriously, go read the post (many of the comments are also very worthy). I'll wait...

And for those of you who didn't click through, here's the part that grabbed me the most:

Outreach is not what we're paid for. Outreach is not what we're awarded things for...And in the scientific world of getting grants, of publish or perish, well, that doesn't fly. If you seem overly interested in outreach (or even in college teaching in some fields), you are not just odd. Your priorities are out of whack. No one ever got a faculty position based on outreach. I have seen colleagues get dinged in promotion meetings for too much time spent doing outreach. The unspoken implication is clear: if you're doing outreach, you must not be doing science.

You don't have to be a psychology graduate student to realize that people respond to incentives. Scientists--people, after all--generally aren't incentivized to do outreach (though the situation is different at liberal arts institutions) so outreach generally doesn't happen. As Kate Clancy points out (based on Katie PhD's comment on Sci's post), this becomes a chicken and egg problem: "we need people to step forward and do outreach, but we also need to make it worth their while...which will only be recognized and understood when more people do outreach." The issue is deeply structural, down to things that seem unrelated at first blush, like how universities are funded and how many grad students are admitted each year.

So most academics don't gain visible, quantifiable, tangible, external rewards for doing outreach about their research. I think that should change. But one thing that's absolutely crucial to keep in mind is that outreach comes with its own intrinsic rewards! Commenter Suzie on Sci's post put it perfectly: "outreach is a profile raising activity, why does no-one ever mention that?... the personal and career-related benefits are more than worth it." Two specific examples of the less-visible-but-still-valuable benefits science outreach can provide: building relationships with peers and senior faculty alike, and building a reputation as a good communicator.

I might not blog as regularly as I'd like to, and I might only get to explain visual illusions to elementary school kids twice per semester, and I almost certainly won't get any meaningful kind of payment or promotion from these activities. But I will continue to make time for them when I can. I'm gaining valuable skills, developing a network, and I enjoy communicating new findings and general excitement for the scientific process! When we feel down on the lack of external rewards for outreach, we should try to remember the many intrinsic benefits it provides as well.