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.

Nest in the city

One of the most incredible things about peafowl is how well these birds thrive in the suburbs. There were hundreds in Arcadia, CA, where I studied them, and every once in a while I hear about some other town where they’ve taken over – Orange County, Palos Verdes, Miami – they even disperse and occasionally pop up somewhere new (like here, or here). I’ve been told that in India (where the species is originally from), flocks also tend to settle down in villages. (And the name for a group of peafowl? A muster!) And peacocks are now on the cover of a book on urban birds1.

So what makes peafowl so much better at urban living than other, similar species?

It could be that they’re catholic about their diets, or that they’re tolerant of a broad range of environmental conditions2. Other research has suggested that, in mammals at least, successful invaders tend to have relatively large brains3 – possibly because a large brain confers the ability to respond flexibly to new situations. American crows fit this theory, as an urban success story with relatively large brains. But peafowl are some of the smallest brained birds out there, when you consider brain size relative to body size – and pigeons, starling and house sparrows aren’t particularly well-endowed, either. So what if it has more to do with how they use their brains to adapt?

A new study points to an intriguing benefit of city life for some birds, and it has me wondering about learning as a mode of urban adaptation. Apparently, some urban birds use cigarette butts to build their nests – and researchers have now shown that the cigarette butts actually improve the living conditions for young birds.

Continue reading →

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.

Very superstitious

The Shark Worlds came to Kingston last month – not a fish thing, but rather the world championships for the Shark class of sailboat. My friend Martin was competing (his boat name? Cloaca. Martin is a biologist who takes taxonomic accuracy seriously).

As he was recounting some of his adventures, he mentioned that he had done quite well in the preliminary practice race. Memories flooded back from my former life as a sailor: “Did you finish it? Never finish the practice race!”


I explained that it was bad luck, especially if you win the practice race. Better to duck the finish line instead of crossing it. Our friend Chris, another evolutionary biologist, dismissed my advice. What did luck have to do with it? We’re rational scientists, right?

I struggled to explain it. “It’s like wearing the conference T-shirt during the conference.” It marks you as new and vulnerable. And if you do well, it does nothing for your mental game. Why set yourself up to have something to lose before the event even begins?

Chris was not convinced, and I’ve been thinking about it ever since – especially since today is a near-miss Friday the 13th. Can someone be rational and superstitious at the same time?

Continue reading →

Monkeys draw from memory

We’re a little bit closer to understanding what it’s like to be a monkey, and it’s thanks to the same technology that powers your smartphone: the touchscreen.

The latest victory for touchscreens is in the field of memory research. Scientists have been studying this ability in animals for decades – some birds, for example, are remarkably good at keeping track of the little details they use when foraging. Florida scrub jays collect thousands of acorns in the fall, hiding them as reserves to help get through the winter. Proof that scrub jays can keep track of multiple pieces of information about their caches – including the type of food, its perishability, and how long it ago it was stored – came from some clever experiments where jays learned to store worms and peanuts in sand-filled ice cube trays in the lab1. Rufous hummingbirds perform a similar feat. They can keep track of flowers on their daily foraging routes, including when the nectar for each one should be replenished, and time their visits accordingly. How do we know? Biologists taught hummingbirds in the Alberta Rockies to feed at artificial flowers that could be refilled on schedule2.

There is also a long history of research on the mental capacities of our closest animal relatives, primates. Rhesus macaque monkeys, a lab favourite used in countless studies of pharmacology and physiology, can easily keep track of a set of objects and spot the difference if you show them an altered version later on3. Not surprisingly, primates seem to have better memories than birds. Baboons can learn thousands of different photographic images and retain these memories for years – incredibly, when this particular study went to press, the baboons were up to 5000 and still hadn’t maxed out their capacity4.  Pigeons, on the other hand, hit a memory wall at roughly 1000 images4. These abilities might prove useful to primates like the chimpanzees living in the Taï National Park of Côte d’Ivoire, Africa. They make extensive use of their vast forest habitat, visiting hundreds of fruit trees that ripen on different schedules5. The Taï chimps can apparently remember where the especially productive trees are, and will often travel longer distances just to get there5.

But there is something missing from this research. It has to do with a subtle distinction in the way memory works: the difference between recognition and recall. Recognition is the ability to identify something because you’ve experienced it in the past. Recall, which can be more difficult, involves retrieving that memory on demand. Ben Basile and Rob Hampton liken it to the difference between a police lineup and talking to a criminal sketch artist. To recognize something is to see it and sense familiarity; to recollect is to create that experience in its absence.

So far all we have been able to study in animals is recognition. Without language, we can’t get them to describe their memories – until now, that is. Basile and Hampton, two scientists from the Yerkes National Primate Research Center in Atlanta, have figured out how to get monkeys to act like criminal sketch artists6.

Continue reading →

I can haz toxoplasmosis

In which you will learn why online cats are so attractive, and discover a new way to lose hours to the internet.

First, the cats. Charlie and I were hashing out the finer points of Facebook, memes and internet superstars, when, in frustration, I brought up his most hated animal.

“Look. Cute baby videos and LOLcats are popular because people send links to their friends. Nobody sits down and says, ‘Well it’s quarter to 10, the same time I always drink my coffee and look for the latest cute cat photos on the–’ ”

Self defeat and laughter mid-sentence, when I remembered living with my friend Jessica in Toronto. She had a brutal job in psychiatric research north of the city. After a hard day, that was exactly what she did. Nothing cheered this woman up like online cat research.

Felis catus is a polarizing species. Some people despise them. Ancient Egyptians and cat ladies have made a religion out of them. The story goes that wild cats were first domesticated in ancient Egypt for useful things like keeping rats out of grain stores and killing poisonous snakes, but this might be more myth than reality. Cats were probably kept around as tame rat-catchers much earlier, certainly before recorded history, and very likely around the beginning of agriculture itself. People were depicting cats on pottery 10,000 years ago1. Cyprus can boast the first Stone Age cat lover. A 9,500 year old burial site on the island is the earliest evidence of humans bonding with these animals, since a cat was intentionally buried alongside a human body there2. The fact that the cat was not butchered, and the inclusion of decorative seashells and stones in the grave, prove that cats had achieved cultural importance beyond their agricultural utility back then.

European wildcat

The European wildcat Felis silvestris is a close relative of the earliest domesticated species. Photo by Péter Csonka from Wikimedia Commons.

But could the cat haters be right – is there something off about feline love? After all, cats aren’t really that useful, at least not when compared to dogs. Dog people might be pleased to hear that when you consider all living and extinct canid and felid species, dogs have bigger brains than cats – probably because they tend to be the more social animals3. Indeed, dogs adapted readily in response to domestication, evolving a number of cognitive abilities that make them particularly good at understanding human gestures – much better, even, than chimpanzees4. Naïve 4-month old puppies will quickly learn what it means when a human points, without any training or close contact with humans beforehand5. Cats can do this too, but they require a lot more effort to learn how6. Dogs can detect certain forms of cancer in humans by smell, and they are often the first ones to notice that something is wrong with their owners7. I have yet to find any high profile studies on feline pathologists. Which raises the question: if cats could do it, would they care enough to try?

And in a bizarre twist, there’s reason to think that our magnetic attraction to cats might be the result of a real parasitic disease.

Continue reading →

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.

Continue reading →

Mind hacks for athletes and the rest of us

For a change of pace, I thought I’d cover two recent neuroscience findings in today’s post. It’s not all academic, either, since both of these studies might help improve your everyday life. Just sit back, suspend your disbelief and fire up the expectation and reward centers of your brain. You might be able to unleash your inner endurance athlete – or epicure, if so inclined – all through the power of the mind.

I’ll start with a surprising finding that I’ve tried to explain to other long-distance runners, who often take a small snack to eat in the middle of a run. I’ve seen the gamut, from orange slices to salty sports drinks and space-age energy gels. The rationale is that these foods quickly replenish the glucose available as blood sugar, the fuel for muscle contraction.

But if you are running for less than an hour, it is biologically impossible for these snacks to improve your performance. For one thing, the amount of carbohydrate that can be effectively absorbed from the stomach to muscle cells in an hour is too small to make any real difference1. And besides, our muscles can hold vast stores of energy in the form glycogen, more than we can possibly use in that span of time, anyway. Spend an hour on a stationary bike, cycling all-out, and you still won’t fully deplete the glycogen in your muscle tissue – so long as you were charged up to begin with2. And yet the snacks work, even in controlled laboratory tests of exercise performance3. No wonder athletes everywhere continue to use them.

Incredibly, this energy boost has nothing to do with caloric consumption, and everything to do with the act of eating.

Continue reading →

A case of mistaken celebrity

They all look the same to us. Celebrities, that is. And by us, I mean academics.

The proof starts with peacocks. Last fall, I was working on some measurements I took of the crest ornament in these birds. Peafowl have this funky little fan of feathers on top of their heads, and though it’s not that small in the grand scheme of fancy bird plumage ornaments, the peacock’s five centimetre crest looks a bit ridiculous next to the metre-and-a-half long train.

Why bother having a crest when you also have a big train? And why do females wear crests too? In this species, the crest appears to be the only plumage ornament shared by both sexes. Here are some of my pictures from the field, taken on the cusp of the breeding season:

Crest ornaments of male and female peafowl

Crests of (a) male and (b-c) female peafowl. Scale bars are 10 cm. Photos by Roslyn Dakin.

Over the years, I’ve measured the crests of close to 150 birds. These data lend some support to the idea that the crest is a signal of health in both males and females, although it might work in slightly different ways for the two sexes1. As you can see from the picture above, there is a lot of variation in how the crests look – and it’s mostly on the female side of the equation. Almost all adult males have tidy looking crests like the one shown in (a), but females often have crests with a lot of new feathers growing in (c). It turns out that males in better condition tend to have fuller, wider crests. The healthiest females, on the other hand, have crests that look most like those of males, with all feathers grown out to the top level (b).

The extreme variability among females leads to an additional hypothesis, and it’s one that I can’t rule out at this time. Perhaps the crest is a signal of individual identity that the birds use to sort out who’s who in their social groups – just as faces do for us. A clue that this could potentially work for peahens is that my field assistants and I can do it. Once you spend enough time hanging around with these birds, you find yourself recognizing certain females that haven’t been captured yet (and that therefore lack identifying leg bands). Your first clue? Usually a unique pattern of crest feathers.

Continue reading →

A royal waste?

Giant pandas are in the news again, this time for their annual date night at the Smithsonian National Zoo in Washington DC. But hardly a day goes by without a report somewhere on the latest captive panda birth, strategic breeding attempt or panda relocation.

A blogger at the London Review of Books compared the bears to members of the British royal family: both are suffering from shrinking ecological niches and in serious danger of extinction, hanging on by virtue of their marketing potential. The similarities don’t end there. Giant pandas, like royals, are expensive to house, with a fee of over $1 million per year for a zoo to lease a pair from China. Naturally, the breeding activities of giant pandas are as intensely scrutinized as those of Prince William.

This entails some surprising efforts when it comes to the pandas. The history of captive breeding for Ailuropoda melanoleuca is no sordid royal affair. It’s long, and for the most part, pretty unfortunate; zoos have been failing to produce heirs to the panda legacy for decades.

For starters, it’s nearly impossible to get the bears to mate in captivity, and it’s not just their deficiency in the looks department, as comedian Mike Birbiglia suggests. Captive pandas can’t seem to figure out a working sexual position1. Females often start things off all wrong by lying down, but the males are just as clueless. This led to panda porn: zoos started making videos of pandas achieving copulatory success, as training tools for the more hapless bears2. Other attempts to use Viagra on pandas were less encouraging, but the porn worked – for females as well as males – leading to a boom in captive births in recent years3.

Giant panda cub

Visitors can pay to see the cubs at the Chengdu giant panda breeding centre. File photo modified from

Continue reading →

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.

Continue reading →

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.

Continue reading →