How do babies learn words?

My 10-month old daughter just proved that she understands some words. Now, when we tell her to “clap your hands”, or even just talk about clapping, we get a round of applause. Pretty cute! This wasn’t one of the things we were actively trying to teach her, like “daddy”, “mommy”, “dog”, or “milk” – I haven’t seen evidence that she knows those yet.

It just goes to show how learning works: motivation trumps deliberate efforts to teach. Clapping is just plain fun.

It’s spooky to think about what else she might come to understand without us knowing.

Peacock Day

Saturday, March 25 was Peacock Day at the Los Angeles Arboretum. I was looking forward to giving a talk at this event for months because it was a chance to return to my stomping grounds at the best time of year.

The event had guided peacock walks, peacock-themed art activities, sitar music, and an Indian food truck (because the species is originally from India). It was a hit – when I arrived in the afternoon there was a huge lineup at the park gates. Total attendance was over 4,400, the biggest day of the year for the Arboretum. There was even a bump in attendance the following day (2,800), because of people who missed the peacocks on Saturday.

My talk was in Ayres Hall (the same building we used to trap many of the females 7 years ago), with 170 people in the audience. I suggested that if we want to give credit where credit is due, we should really call it Peahen Day, because peahens are responsible for the evolution of the peacock’s amazing display.

I also talked about why I think the species does so well in California (and other places). I think it’s because peafowl are social (they stick together as an effective defense against most predators), because they are quick learners, and because the chicks spend a long period of time following mom – around 9 months, actually. That’s a long time for a bird! It provides many opportunities for mom to transmit skills that allow her offspring to handle new environments, like what to eat, how to hide, and even how to cross the road.

I think the main thing we’ve learned from our research on peafowl is the importance of dynamic signals during mate choice. i.e., it’s not just what a peacock has that makes him beautiful, but also how he uses it. A major theme in evolution research today is whether sexual selection speeds or hinders adaptation. Although we don’t yet know whether sexual selection has promoted adaptation in peafowl, we can say that they have spread around the world because of their sexually-selected traits. We brought peacocks to California, Hawaii, Florida, New Zealand, and many other places, because they are beautiful in our eyes as well as those of the peahen.

Troubleshooting and iteration in science

The scientific method is taught as far back as elementary school. But students almost never get to experience what I think is the best part: what you do when something goes wrong. That’s too bad because self-correction is a hallmark of science.

In ecology and evolution, most graduate students don’t get to experience iteration firsthand, because they are often collecting data right up until the end of their degree. I didn’t experience it until my postdoc, when we failed to repeat a previous experiment. It took several experiments and a lot of time  – two years! – to figure out why. In the end, it was one of the most rewarding things I’ve done.

Wouldn’t it be great if undergraduate students actually got to do this as part of their lab courses (i.e., revise and repeat an experiment), rather than just writing about it?

One thing that can come close – teaching you how to revise and repeat when something doesn’t work – is learning to code.

How to mentor

Yesterday I was asked about how I mentor in research. This is an area where I still have a lot to learn, however, there are at least four things that I think are really important:

1. Confidence**.
Instilling confidence is probably the most important thing a mentor can do. Science is about unknowns and learning how to become an expert. And that requires confidence.

So how do you instill confidence?

2. Basic programming and learning how to “script”.
This was a real catalyst for me and a huge boost to my confidence. Once I had mastered some basic programming in R, it allowed me to start treating data like an experimental subject. Want to understand what happens when you ignore pseudoreplication in your data? What about how collinearity might influence the results of your analysis? It’s not too hard to write a simulation to figure that out. A lot of basic programming is troubleshooting, a useful and transferable skill. Acting like an experimenter also comes naturally – I see it all the time with my 4-month-old daughter!

Learning how to write scripts is also key to making your workflow efficient and reproducible. Filtering, tidying, and graphing your data is 90% of the work. Doing that through code is way more efficient and leaves a record of what you did, making it easier to correct errors later on. And if you can generate publication-quality graphs purely through code, it will save you a huge amount of time making tweaks. And believe me, you will need have to make a lot of tweaks. Finally, scripting means your work can be used by others (including, and perhaps especially, your future self).

3. Students are scientists, too.
There is nothing I’ve done that couldn’t be done by an undergraduate, if they had enough time. One of the best things grad school was our weekly seminar series. We’d have an MSc exit seminar one week followed by a distinguished visiting professor the next. As a student, your work is every bit as important.

4. Treating feedback as an opportunity.
I think it’s important to provide students with lots of constructive feedback – and also, to help them develop an ability to deal with it. In science (and in life), rejection happens. I got another huge boost when I stopped worrying about negative feedback and started looking at it as a problem-solving opportunity. This is a broadly transferable skill.

Taken together, the points above are pretty circular: it takes confidence to handle feedback, but also dealing with feedback forces you to gain confidence. So “fake it until you make it” really works. As a mentor, I think it’s important to treat students as fellow scientists, to provide them with lots of opportunities to act as peer reviewers and reviewees, and to model the process of using feedback to solve problems.

Update to #1 above, on confidence: I also try to emphasize that the value of science is based on the quality of the data collected and clear dissemination of the results – and not whether it supports a particular hypothesis, or has a p-value < 0.05. I think this is a major stumbling block for a lot of students. Your thesis does not hang on the results of one test! The cure to this kind of thinking includes a better understanding of what p-values really mean and the limitations of null hypothesis statistical testing (NHST), and a focus on reporting the data (including effect sizes, confidence intervals, and individual variation).

** Related: I think a lack of confidence is a major cause of the leaky pipeline for women in STEM (and perhaps other under-represented groups). Many women choose careers outside of science despite aptitude (see for example this 2009 study by Ceci et al.). There’s some very recent evidence that gender stereotypes about aptitude – which could shape children’s interests as well as their confidence – begin as early as 6 years old (see here).

Learning to science

From Alison Gopnik’s The Gardener and the Carpenter:

Imagine if we taught baseball the way we teach science. Until they were twelve, children would read about baseball technique and history, and occasionally hear inspirational stories of the great baseball players. They would fill out quizzes about baseball rules. College undergraduates might be allowed, under strict supervision, to reproduce famous historic baseball plays. But only in the second or third year of graduate school, would they, at last, actually get to play a game.

The currency on campus

My article on the behavioural economics of grades is out, and it’s the cover story this month in University Affairs magazine!

I had a blast doing interviews for this story. I tried to pick profs with a reputation for being great teachers in classes that are popular despite being tough. I learned a ton talking to them, but I have to say I was disappointed that I couldn’t take this story further. I was hoping for something more conclusive about how behavioural economics could be applied to grades. We know that humans aren’t particularly rational when it comes to incentives, and grades perform a dual feedback/incentive role – and yet we have no idea how students respond to grading schemes, or whether some of the most common practices might be entirely counterproductive. In the end, I think the incentive effect of grades is something that we should be studying experimentally.

Quirks, quarks and quantum sailboats

An old mystery from my days as a sailor resurfaced this week. Does air on one side of the sail somehow know what the air on the other side is doing? Sounds strange, but it happens to be a key part of explaining how boats, birds and airplanes work, and it stumps a whole lot of people who should probably know better – including most pilots.

I was reminded of this by Bob McDonald from CBC’s Quirks and Quarks radio show. He was in town to give a talk on “The Science of Everyday Life”. It was clear that this was going to be a show for kids, but I dragged Charlie along for two reasons. First, I was planning on presenting some of my peacock research at a family science festival on Saturday; I thought it might be useful to see a master of this sort of thing in action. Fandom came into it too – the Quirks show is one of a handful of radio programs that got me through my troglobite period of 8 hour days in the darkroom last summer.

I was pretty sure what we were in for – baking soda and vinegar magic for the edification of the grade school set – but I wasn’t prepared for how quickly McDonald would put me under his spell, too. Sitting there cold and hungry in the dingy auditorium, I had forgotten all about my surroundings by the time McDonald was whirling a mop around and keeping a kid trapped in his chair using only his thumb to demonstrate centre of gravity. And he was just getting started. Although the talk was too long at nearly 2 hours, it was worth the wait to see video of McDonald’s adventures in weightless flight at the end. His imaginative pitch for the space tourism industry was another highlight. I was hooked at his concept for a giant rotating space hotel. If we put a cylindrical swimming pool smack in the middle, the water would stick to the outer walls by centripetal forces. You could literally fly around in the air at the zero-gravity centre and dive down in any direction to the water below.

McDonald mentioned something in his explanation of how to make a better paper airplane that brought up an old problem for me.

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To kill bias, gather good data

I hate myself for this: I have the worst sense of direction.

For the entire year when I was living in my first apartment in Kingston, I would take a circuitous route along King Street and then up Princess on my way home from the Kingston Yacht Club. Nearly two kilometers, when walking up West Street would have got me home in half the time. As Charlie said when I revealed this to him, “Two sides of a triangle is always greater than one.”

It’s not that I didn’t know grade school geometry, or that I wanted a more scenic route. I just stuck to the path I knew would get me there.

I felt a bit triumphant when I realized how long it can take Charlie when you ask him to pick up the milk. The last time I dragged him to the grocery store, I left him alone for a few minutes to use the bathroom, and returned to find him loading pineapple after pineapple after pineapple – painfully slowly, into the cart. We laughed, but I don’t ask him to come with me anymore. Alone, I can collect a week’s worth of food in less than 20 minutes.

I’m not ashamed to admit my navigational failings, either. My field assistant Myra and I happily agreed that our best strategy driving around Los Angeles was that we should always do the opposite of whatever we both thought was correct. It worked.

What I hate is my sneaking suspicion that I’m just a lame stereotype. Maybe I’m a terrible navigator because of biology; female brains are just not suited for getting around.

Hunter, gatherer

Modified from this cartoon. Original source unknown.

Recently, psychologists looked at this sex difference in what seemed like a neat field study of human foraging behaviour – in a grocery store1. Joshua New from Yale University, and his coauthors from UC Santa Barbara, set up a unique experiment in a California farmers’ market: they led men and women around the market, giving them samples like apples, fennel, almonds and honey. Then they brought the subjects back to a central location and asked them to point in the direction of those same food items.

These researchers wanted to test the idea that women outperform men at certain kinds of spatial tasks: while men are thought to be better at vector-based navigation, women might excel at remembering the locations of objects, because of the way foraging roles were divided up when our brains were evolving. It’s thought that in our hunter-gatherer past, big game hunting meant that men had to figure out how to bring heavy prey home by the most direct route. Women foraging closer to home needed a much different set of spatial adaptations2. It’s not that men are better at spatial reasoning in general, you just have to choose the right task3.

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Wherefore the mustache?

Ears, palms, toes, neck, and nose. In that order.

These are the grossest places for humans to have hair, according to Queen’s students. Ok, there were a few others that I didn’t mention. The upper lip, however, did not receive a single vote.

Last fall a number of men in the biology department grew competitive mustaches for “Movember” prostate cancer research fundraising. This required mass beard shaving on the first of November. Martin Mallet, known for his thick coat of fur, emphatic hand gestures and all-around intensity, suddenly transformed into a meek imposter. For the first time Martin had no probing questions for the speaker at the EEB seminar. I can’t help but wonder: if he did, would anyone have noticed?

I started to recognize Martin again when the hair on his upper lip attained visibility. Other men of Movember fared less well. It can’t be a good thing when the people who work in the same office as you don’t even notice your new, mustachioed face.

But what, if anything, is it for? My experience suggests that human facial hair serves as a male status signal. Is this why we evolved mustaches in the first place?

Inca Tern

Why do mustaches evolve? Inca tern, from Wikimedia Commons.

In class the other week we discussed Stephen Jay Gould and the trouble with adaptationism. Gould famously criticized the proliferation of sloppy adaptive reasoning in his 1979 paper “The Spandrels of San Marco and the Panglossian Paradigm1. He took aim at scientists who apply adaptive “story-telling” to nearly anything – from the colour of our skin to the size of our noses – in an unverifiable, unfalsifiable way.

It can be easy to jump on the adaptationist bandwagon, since these stories are often quite plausible. This may have been especially true when “Spandrels” was written, due to the rise of some revolutionary ideas about how to apply evolutionary biology to the study of social behaviour. There was plenty of new research to be done. Of course, many of the people doing this research disagreed with Gould’s characterization2. At its worst, adaptationist thinking might lead to some bad science, especially when it comes to human behaviour (where confounds are especially hard to control). But speculation is a necessary part of the scientific method, and adaptive reasoning can be a good place to start.

It is worth noting that Gould’s paper has been enormously influential. “Spandrels” has been cited well over 3500 times. I’m still waiting on citation number 3 for my Master’s research.

And yet, the response of the research community to the “Spandrels” critique has largely been, “That’s well said, but let’s get back to our field work.”2 In that spirit, consider the mustache. Can we speculate about it in a reasonable way, avoiding the big adaptationist pitfalls?

First of all, is this question worth asking?

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Science fictions

Fakery is not just for Hollywood films anymore.

Nature documentaries are full of it, from elegant narratives to some downright dirty tricks. This tradition goes back a long way: the myth that lemmings commit mass suicide to save their brethren from overpopulation was spread widely as as result of the 1958 Disney film White Wilderness. This is not trivial. The film won an Oscar for Best Documentary. The lemming story made it as far as a philosophy course I took in university (Science and Society PHIL203), where the instructor used it as an example of why we should doubt evolutionary explanations of human behaviour. The myth just won’t die, even though CBC exposed the lemming scam back in 19821. Journalists on The Fifth Estate proved that the mass suicide scene was actually filmed in downtown Calgary, not in the Arctic as Disney had claimed. The Disney crew used a rotating platform to push captive lemmings into the Bow River.

More recently, the BBC has come under fire for using captive animals to film some of the scenes in the Blue Planet series1. This seems justifiable to me, but some truly ugly practices have also been exposed, like baiting corpses with M&Ms to get footage for an IMAX documentary on wolves2.

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Field biology goes to Hollywood

One of the weirder things about my field site is that it is also a Hollywood set. A number of movies, TV shows and commercials have been filmed at the LA Arboretum, going back to Tarzan Escapes in the 1930s.

The Arboretum had a regular appearance in the popular 1970s show Fantasy Island. In the opening credits, a midget rings the bell in the Queen Anne Cottage. This is a historic building on the Arboretum grounds that was built in the by the same wealthy California businessman who started the peafowl population in the area.

You can catch the Arboretum in many other films, since it provides a convenient stand in for the jungle a short drive away from downtown Los Angeles. Examples: The Lord of the Flies, Anaconda, The Lost World, Congo, Terminator 2, The African Queen, and too many campy horror flicks to count (Attack of the Giant Leeches?).

Several things were filmed during my three seasons there, leading me to realize that making a movie is a lot like doing field biology. Here’s how:

1. The hours. Field biologists often have to keep the same hours as their study species, working for as long as the animals are active. For some ornithologists, this can mean starting at 4 am. We were lucky with peafowl. They are late risers, coming down from their roosts around 7-8 am. They also tend to take a long siesta in the middle of the day. This meant that we had to work two shifts, coming in for several hours in the morning and returning after lunch until sunset. It made for some long days.

Film crews also seem to work long hours based on the amount of light, since our schedules would often coincide.

2. Tedium and futility. Most of the time spent watching animal behaviour is watching them do very little. Here’s an example: we saw about 20 mating events in 2010, in 500 man-hours of observation time. That’s over 24 hours of sitting quietly for each copulation.

Catching the beasts can be a little bit more active, but you still feel completely useless 90% of the time. Your main activities include: waiting for the animals to show up, looking for the ones you haven’t caught yet, waiting around for your traps to work, and worrying about all the reasons why they aren’t.

A lot of jobs in Hollywood might not be so far off. When AT&T filmed a commercial at the Arboretum last year, we met a guy whose sole responsibility was to keep the peacocks away from the set. His boss gave him a bag of bird seed. It was the cusp of the breeding season, and the crew had decided to place their set right in the middle of one particularly dedicated male’s territory. The poor guy was literally playing tag with that bird all day.

3. Costumes. Important in Hollywood, but also useful when trying to catch birds. After a few weeks in the field, most tend to settle in to a uniform, wearing the same thing nearly every day. If it works and you’ll just be getting dirty again tomorrow, why change?

Field clothes

Waterproof jackets come in handy when catching large birds. From left: Will Roberts, Myra Burrell and Roz Dakin. Photo by Bonny Chan.

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How to raise a science major

The newspapers have been abuzz lately about a controversial book: Battle Hymn of the Tiger Mother, by Amy Chua, is a memoir on the rewards and perils of stereotypically strict Asian-American parenting. This week I asked students in my 4th-year biology class to tell me about their earliest memory of being fascinated with something biological, information that could be useful for parents hoping to form their children into university science majors.

And so, some lessons learned:

1. Worms work. Let your kids get close to the ground, outside. At least two students listed earthworms appearing after the rain as their most important early memory. A large portion of the class described similar encounters with tadpoles, snails, caterpillars, ants, spiders and their webs, and other minutiae found on the lawn. Larger examples of charismatic megafauna barely got a mention. Perhaps opportunity plays a role. For instance, one student remembers being particularly enamoured with deer in the backyard.

2. Pain. A wise teacher once told me that “learning hurts”. The converse might also be true: harmful organisms can be educational. An encounter with razor-sharp zebra mussels was particularly salient for one student. Another recounted a family vacation in the New Mexico desert, where a first-hand experience with cacti led to an early lesson in adaptation.

Well-armed cacti

Hidden Valley, Joshua Tree National Park, California.

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What should Stephen Harper know about biology?

I’m teaching again this semester, this time in Bob Montgomerie’s fourth-year course on the history and philosophy of biology. My job is to moderate group discussions and seminars in the tutorials. It will be a lot of work, since tutorials happen every week, but I’m excited at the prospect of using our debate as fuel for this blog.

I started by asking the class to answer three questions in an anonymous survey. First, I wanted them to tell me the most surprising thing they had recently learned about science.

My example of this was the nocebo effect. it’s the opposite of the placebo effect, with a bit of voodoo-witchcraft thrown in: apparently just believing in a negative outcome can be bad for your health. What I found surprising about it initially were the spooky anecdotal accounts of people diagnosed with terminal illness, and then dying within a few months just as the doctors predicted – only to have pathologists later realize that the original diagnosis was in error. Can we think ourselves to death?

But maybe this was a bad example. In general, the power of negative thinking isn’t all that surprising. Why shouldn’t there be a flip side of the coin for the placebo effect? After all, the negative effects of stress and anxiety on health are well-documented by the medical community. For example, this Washington Post article describes a study on blood thinning drugs where doctors showed that just by giving patients a warning about gastrointestinal side effects, you can make it much more likely that they will experience those negative symptoms. Other documented nocebo effects in the Skeptic’s Dictionary range from headaches to allergic reactions. Again, the power of thought to affect us via our own immune systems is perhaps not so surprising.

Voodoo may have lost its magic too: according to this article from Salon, there is some debate as to whether examples of death by curse in tribal societies are really due to starvation and dehydration, since feeding the doomed individual is often seen as a waste of scarce resources. And of course, the medical anecdotes of death by false diagnosis are good stories, but probably not much more than eerie and highly memorable coincidences.

What do the students find hard to believe? Out of 28 responses, 4 had to do with the paradoxical nature of modern physics. There was 1 response on lemmings that was certainly hard to believe, because it was just plain wrong (more on that later, but lemmings do not jump off of cliffs in a form of altruistic mass suicide. That is a myth). The majority, at 14, were on marvels of adaptive evolution (e.g., the complexity of the brain, venomous mammals like the platypus, bowerbirds, examples of rapid evolution).

This is proof that majoring in biology does not diminish the sense of wonder we have about living things. If anything, it probably enhances it. Here are two student responses that sum it up nicely: the “diversity that surrounds us” and “just how much there is out there to learn”. It may be the hardest thing about biology to really wrap your mind around, but it sure is fun to try.

The second question: What should Stephen Harper know about biology?

The most popular category here was the environment, with 13 students listing principles of ecology and environmental science that Harper could use. After that, 4 wanted Harper to have a basic grasp of evolution and natural selection, especially given the strange opinions of his science minister Gary Goodyear. There were 2 shameless requests for more research funding. Sadly, 2 left this one blank – hopefully not because they think Harper doesn’t need any biology. At the other extreme, 1 complained that there is a lot Harper should know about “any matter really”. One student wants him to have “a dangerous idea like Charles Darwin”.

I would tell Stephen Harper that Taq polymerase comes from Yellowstone National Park. Everyone should know this one – I’m sure I learned it during undergraduate, but forgot, only to be reminded of it again recently.

Here’s the story: Taq polymerase is a chemical we use to study DNA. A workhorse of the modern genetics lab, this enzyme makes it possible to turn a minuscule amount of DNA into a much larger sample by rapidly copying the molecules at high temperatures in the polymerase chain reaction (PCR). Countless techniques are made possible as a result: forensic DNA fingerprinting, diagnosis of genetic diseases, unraveling gene functions, sequencing whole genomes, and filling in the branches on the tree of life that describes how all living things are related to one another.

Taq polymerase works at high temperatures because it comes from Thermus aquaticus, a heat-loving bacteria. Up until the 1960s, the temperature threshold for life was thought to be around 73 degrees Celsius (which is the limit for photosynthetic bacteria). However, in 1967 Thomas D. Brock and Hudson Freeze reported finding bacteria that could withstand temperatures a lot higher than that in the hot springs of Yellowstone. This was revolutionary. Years later, when people were working out the chemical procedures necessary for DNA analysis, it was knowledge of the earlier Yellowstone discovery that made efficient DNA copying at high temperatures possible.

I also asked the students what they hoped to get out of the course. Only 1 claimed a good mark, which was surprising for an anonymous survey. Some emphasized novelty: to learn “something new in biology for once”, “something stimulating and eyebrow raising” and “ideas never thought of before”. Others hope to learn some personal and biographical details of the iconic figures in science: “what inspired them” and “what was going through their heads when their ideas were opposing the popular belief of their time”. I hope I can learn from this group about what goes on in the heads of students and the public in Canada.

Biology 210 Magazine Article

Popular science writing style

Olivia Judson’s blog for the New York Times is an excellent example of the sharp-but-accurate style you should aim for, although the posts are much shorter and don’t into as much detail as you will for the assignment. Here are a couple of quick reads for inspiration:

An Evolve-By Date

Laboratory Life

Judson also lists her primary sources at the end, as further readings.

Feature-length articles

Examples of longer feature articles. This one from the New York Times covers research from the lab of Meredith Chivers, a Queen’s professor in the Psychology Department who works on sexuality and gender:

What Do Women Want?

More examples from New Scientist magazine. The first article is on sexual conflict down to the level of gametes, and the second is on same-sex behaviour in animals:

Dad vs. Mom: The Ultimate Battle of the Sexes

Homosexual Selection

And finally, another feature-length piece from Science News magazine covering the latest research and opinions about sex differences in science and math aptitude:

Showdown at Sex Gap