Why are so few foods blue?

Why are so few foods blue?

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Although blue foods exist, they're rare enough compared to other foods for food preparers to use blue plasters as a convention. The natural colour of a given food is due to pigments that have some biological origin. Is there any evolutionary reason why these are rarely blue?

Short answer
Blue color is not only rare in edible organisms - Blue color is rare in both the animal and plant Kingdoms in general. In animals, blue coloring is generated through structural optic light effects, and not through colored pigments. In the few blue-colored plants, the blue color is generated by blue pigment, namely anthocyanins. The reason for the scarcity of blue pigments remains unknown as far as I know.

The vast majority of animals are incapable of making blue pigments, but the reason appears to be unknown, according to NPR. In fact, not one vertebrate is known to be able to. Even brilliantly blue peacock feathers or a blue eye, for example, don't contain blue pigment. Instead, they all rely on structural colors to appear blue. Structural colors are brought about by the physical properties of delicately arranged micro- and nanostructures.

Blue morpho butterflies are a great example of a brilliant blue color brought about by structural colors. Morphos have a 6-inch wingspan - one side a dull brown and the other a vibrant, reflective blue. The butterflies have tiny transparent structures on the surface of their wings that scatter light in just the right way to make them appear a vibrant blue. But if you grind up the wings, the dust - robbed of its reflective prism structures - would just look gray or brown.

Similarly, the poison dart frog is blue because of the iridiphores in its skin, which contain no pigment but instead feature mirror-like plates that scatter and reflect blue light (source: By Bio).

Morpho and poison dart frog. sources: Wikipedia & LJN Herpetology

Similarly, in the Kingdom of plants less than 10 percent of the 280,000 species of flowering plants produce blue flowers. In fact, there is no true blue pigment in plants and blue is even more rare in foliage than it is in flowers. Blue hues in plants are also generated by floral trickery with the common red anthocyanin pigments. Plants tweak, or modify, the red anthocyanin pigments to make blue flowers, including pH shifts and mixing of pigments, molecules and ions. These complicated alterations, combined with reflected light through the pigments, create the blue hue (source: Mother Nature Network).

But why the blue pigments are so scarce, seems to be unknown as far as I know (MNN, NPR, Science blogs)

- Photobiology

Although @AliceD's answer is a great simple demonstration of the rarity of blue in our natural world, there's likely a more nuanced/technical reason.

Short answer

Blue light was the most available wavelength of light for early plants growing underwater, which likely led to the initial development/evolution of chlorophyll-mediated photosytems still seen in modern plants. Blue light is the most available, most high-energy light that continues to reach plants, and therefore plants have no reason not to continue taking advantage of this abundant high energy light for photosynthesis.

Different pigments absorb different wavelengths of light, so plants would ideally incorporate pigments that can absorb the most available light. This is the case as both chlorophyll a and b absorb primarily blue light. (Absorption of red light likely evolved once plants moved on land due to its higher efficiency).

Pigments appear as whatever color is not absorbed (i.e, they appear as whichever wavelength(s) of light they reflect). Because blue pigment would reflect the majority of light that modern plants rely on for their chlorophyll-mediated photosystems, blue pigments remain scarce in plants.

  • Photosynthetic organisms would not remain competitive if they failed to absorb the readily available, high-energy blue light, and so therefore evolution has likely very infrequently favored the generation (or propogaiton) of blue pigments.

Long Answer

Atmospheric Transmission

As this page from Humboldt State University demonstrates, blue and green light pass through the atmosphere to the earth's surface better than almost all other wavelengths of light:

transmission is when electromagnetic energy is able to pass through the atmosphere and reach the surface. Visible light, largely passes (is transmitted) through the atmosphere.

This means that blue and green light are the most available wavelengths of light.

  • Note that blue/green are followed closely by the rest of the visible spectrum and NIR (near infrared).

  • Also note that a large portion of ultraviolet is largely absorbed by atmospheric gases (primarily ozone), and therefore poorly transmitted.

Wave Properties

It's important to understand that (from U. Wisconsin):

More energetic waves have shorter wavelengths while less energetic waves have longer wavelengths.

As a result, blue light (being the most available highest energy wavelength of light), seems to be the optimal wavelength of light for photosynthesis.

  • Note that although available UV light is more energetic and can power photosynthesis, it's often a tad too energetic and can cause damage to cells. So it's often best for organisms to reflect UV.

  • More info about the physics behind light energy can be found here.


Photosynthesizing organisms contain pigments (typically heme/porphyrin-based chlorophylls and various carotenoids) that absorb light energy. Basically, the energy from a photon of light raises an absorbant pigment to a higher energy state (called an excited state), and then the pigment releases that unstable energy to return to it's ground state -- this excess energy is what powers the biochemical reactions of photosynthesis. See here for more details.

Here's two example graphs (from here and here) showing the absorption spectrum of typical plant pigments:

As you can see, plants have evolved to have pigments that absorb primarily blue light (followed by red light). These pigments reflect green light and so therefore appear green.

  • Presence of blue pigments (i.e., those that reflect highly abundant blue light), on the other hand, would be in direct contrast to these photosynthetic efforts. As a result, blue pigments remain rare in photosynthetic organisms powered primarily by chlorophyll-driven photosystems.

However a number of sources (e.g., Mae et al. 2000, Brins et al. 2000, and here) suggest that although plants absorb more blue light than other wavelengths, the most efficient photosynthesis does not occur using blue light. Instead, red light results in the highest photosynthetic efficiency.

  • One of the reasons that they (in this case Brins et al) found was that xanthophylls were dissipating the excess energy associated with blue light causing a rate decrease in blue-light photosynthesis.

  • This NIH page suggests that high-energy light isn't even necessary for plants:

    Chlorophyll a also absorbs light at discrete wavelengths shorter than 680 nm (see Figure 16-37b). Such absorption raises the molecule into one of several higher excited states, which decay within 10−12 seconds (1 picosecond, ps) to the first excited state P*, with loss of the extra energy as heat. Photochemical charge separation occurs only from the first excited state of the reaction-center chlorophyll a, P*. This means that the quantum yield - the amount of photosynthesis per absorbed photon - is the same for all wavelengths of visible light shorter than 680 nm.

However, all of this may be for nought, because there is ample sunlight available to plants. Again from the NIH page:

However, even at the maximum light intensity encountered by photosynthetic organisms (tropical noontime sun, ≈1.2 × 1020 photons/m2/s), each reaction-center chlorophyll a absorbs about one photon per second, which is not enough to support photosynthesis sufficient for the needs of the plant. To increase the efficiency of photosynthesis, especially at more typical light intensities, organisms utilize additional light-absorbing pigments.

In other words, plants are not entirely photosynthetically efficient and do not typically use all of the light available to them. From Wikipedia:

Photosynthesis increases linearly with light intensity at low intensity, but at higher intensity this is no longer the case (see Photosynthesis-irradiance curve). Above about 10,000 lux or ~100 watts/square meter the rate no longer increases. Thus, most plants can only utilize ~10% of full mid-day sunlight intensity.

So in summary:

  • Blue and green light are the most available wavelengths of light.
  • Blue light is the most energy-rich of the high-availability wavelengths of light
  • Plant pigments absorb mostly blue light
  • BUT plants don't necessarily need the high energy of blue light for efficient photosynthesis.

So what gives?…


So given all of that, the question still remains: why absorb mostly blue light and not green light?

The answer, though still somewhat conjectural, is likely due to the light availability of early plants. Early plants evolved, like all life, under water.

It turns out, just like the variability in transmittance of different wavelengths of light through the atmosphere, certain wavelengths of light are more capable of penetrating deeper depths of water. Blue light typically travels to deeper depths than all other visible wavelengths of light. Therefore, the earliest plants would have evolved to concentrate on absorbing this part of the EM spectrum.

However, you'll notice that green light penetrates relatively deeply as well. The current understanding is that the earliest photosynthetic organisms were aquatic archaea, and (based on modern examples of these ancient organisms) these archaea used bacteriorhopsin to absorb most of the green light.

Early plants grew below these purple bacteriorhopsin-producing prokaryotes and had to use whatever light they could get. As a result, the chlorophyll system developed in plants to use the light available to them. In other words, based on the deeper penetrative ability of blue/green light and the loss of the availability of green light to pelagic prokaryotes above, plants evolved a photosystem to absorb primarily in the blue spectrum because that was the light most available to them.

So why have plants not evolved to use green light after moving/evolving on land? As stated above, plants are terribly inefficient and can't use all of the light available to them. As a result, there is likely no competitive advantage to evolve a drastically different photosystem (i.e., involving green-absorbing pigments). So earth's plants continue to absorb blue light and reflect the green, and blue pigmentation remain uncommon in our world.

  • Plants likely evolved to produce anthocyanins (the pigments responsible for the reds/blues/purples attributed to blueberries and violets) for reasons other than photosynthesis -- e.g., attraction, UV protection, or even protection against herbivores. See here, here, and here for examples.

So what about non-plant organisms?

According to Wikipedia:

  • Carotenoids are the most common group of pigments found in nature, including in animals.
  • Carotenoproteins complexes are responsible for the various colors (red, purple, blue, green, etc.)
  • Animals are incapable of making their own carotenoids and thus rely on plants for these pigments.

In other words, most pigments in non-plant organisms originate either directly or biochemically from the organism's diet. Without direct ingestion of blue pigments, these chemicals are unavailable or biochemically expensive to produce (see Crustacyanin). As a result, blue pigments are also uncommon in animals.

Though, as AliceD's sources point out, we still don't fully understand why animals don't produce more blue pigments.

It is not that there are no blue foods, it is that the English language does not like calling foods "blue".

There are no natural borders between "colors" in a colorspace, all colors we name (and learn to distinguish) are culturally defined. So, an important thing to recognize is that, a color somebody calls "blue" can be called "purple", "red" or "maroon" or "green" or something else.

With that in mind, we can take a look at foods. Animal foods on the inside are protein, and cooked protein is usually a pale greyish goo (although muscle cooked medium still has reddish coloring). One of the rare examples would be some eggs with blue shells. In plants, basically all leaves we eat are colored by chlorophyl. So they are out of the equation.

Other plant parts, especially fruits, tend to be colored by one of a few other groups of pigments. And a major group of those pigments, the anthocyanins, ranges from blue to purple to red (they also change with pH). So a ton of foods have a somewhat purplish blue color, and are also named "blue" in other languages. Plums, aubergines, red grapes, red cabbage, and many berries are good examples for that. Then you have some plants which come in many colors, but the major cultivars happen to not be blue - potatoes and maize are the first to come to mind.

Other shades of blue are less common just because they don't happen to be covered by the major pigment groups, but if you go down into shade level, then "royal blue" is just one of many on the spectrum which is missing. Also note that there are still plants which have other shades of blue and are consumed, they are just not commonly thought of as "food". Lavender, chicoree, gentian and pansies all have blue flowers of various shades and are traditionally used in recipes.

So there is no special evolutionary reason why plants or animals should not be blue - many of them are blue, and we eat some of the blue ones. It is simply a cultural or linguistic trend for English speaking people to not see their food as blue.

Why Aren't There More Blue Flowers?

There's a reason the intensely blue orchid flowers you’ve seen in the floral departments of groceries, box stores and retail plant nurseries don’t look natural.

Blue isn’t a natural color in these types of orchids. These are white flowers that get their color from a dye used by plant breeders. In fact, “blue is a color that is infrequent in nature,” said David Lee, author of "Nature’s Palette: The Science of Plant Color" and a retired professor in the Department of Biological Sciences at Florida International University in Miami. “Less than 10 percent of the 280,000 species of flowering plants produce blue flowers,” he said.

But for the first time, a group of scientists say they have genetically engineered a flower — a chrysanthemum — to produce a blue hue. "Chrysanthemums, roses, carnations and lilies are major floricultural plants, [but] they do not have blue flower cultivars," Naonobu Noda, lead study author and scientist at Japan's National Agriculture and Food Research Organisation, told Gizmodo. "None has been able to generate blue flower cultivar by general breeding technique."

The researchers used genes from two other blue-flower-producing plants, butterfly peas and Canterbury bells, and mixed those genes with chrysanthemums. As Gizmodo reports, the resultant color was the work of "co-pigmentation," an intra-flower chemical interaction that they hope will also help turn other popular flowers blue.

The Nature of Crops: Why do we eat so few of the edible plants?

WALK around a farmers’ market or the fruit and vegetable aisles in a supermarket and the overwhelming impression is the sheer abundance of colour, form, smell and anticipated flavour. But talk to a botanist, and they will say that it is in fact rather a poor show.


Of Earth’s estimated 400,000 plant species, we could eat some 300,000, armed with the right imagination, boldness and preparation. Yet humans, possibly the supreme generalist, eat a mere 200 species globally, and half our plant-sourced protein and calories come from just three: maize, rice and wheat.

The obvious questions are why so few and why these crops? In The Nature of Crops, agronomist John Warren takes us on a journey through history where chance, fashion and the ingenious exploitation of biological adaptations interweave. It really didn’t have to be like this. Fat hen, for example, formerly a staple, could still rule the plate, and kiwi remain a pickable fruit alongside China’s rural roads.

If he lectures as he writes, Warren’s courses at Aberystwyth University, UK, must be a joy – the book is full of quirky stories. We learn that their malodorous flowers meant that species in the chocolate family (Sterculiaceae) were named after the Roman god of manure, Sterculius. We also ponder who in their right mind thought of eating toxin-packed ankee, cashews and cassava, and explore the sexual trials of being a male pecan nut tree and the food potential of clover.

Glorious in breadth and fascinating in depth, all the short stories means The Nature of Crops can be read and reread in the room where Sterculius is king.

The Nature of Crops: How we came to eat the plants we do

This article appeared in print under the headline “Spoilt for choice”

(*When you buy through links on this page we may earn a small commission, but this plays no role in what we review or our opinion of it.)

Why Are There So Many Pigeons?

They peck at the pavement they coo overhead they swoop in hundreds across town squares: Pigeons have become such a permanent fixture in our urban landscapes that cities would seem oddly vacant without them.

But while many people harbor resentment for these ubiquitous creatures — labeling them "rats with wings" — few of us stop to ponder how pigeons became so numerous in the first place, and what our own role in their urban colonization might be.

Today, in fact, there are more than 400 million pigeons worldwide, most of which live in cities. But that wasn't always the case. The city pigeons we know today are actually descended from a wild creature known as the rock dove (Columba livia): As its name suggests, this bird prefers a rocky coastal cliff habitat to the conveniences of city life. [Why Are Chickens So Bad at Flying?]

But going as far back as 10,000 years ago, written and fossil records show that people living in ancient Mesopotamia (modern-day Iraq) and Egypt began coaxing these doves with food into human-inhabited areas, encouraging them to roost and breed on their land. "Back then, we brought rock doves into cities to eat as livestock," Steve Portugal, a comparative ecophysiologist who studies bird flight and behavior, told Live Science. The plump, young birds especially — known as "squabs" — became a prized source of protein and fat. People then began domesticating and breeding the birds for food, creating subspecies that led to the diversity of urban pigeons known today.

Along the way, humans began to realize that pigeons were useful for much more than their meat. As the birds grew more popular in the Middle East, North Africa and Western Europe in the ensuing centuries, people began to tap into their innate talent for navigation — the same skill that makes homing pigeons famous today. Ancient records show that Mediterranean sailors used the birds to point floundering ships toward land. In cities, they became increasingly valuable as airborne messengers that could deliver important information across large distances.

From there, humanity's appreciation for the animals only grew: Although pigeons were initially domesticated as a food source, "as other poultry became more popular, pigeons fell out of favor for eating and people began breeding them as a hobby," said Elizabeth Carlen, a doctoral student at Fordham University in New York City who studies the evolution of urban pigeons.

By the 1600s, rock doves — non-native to the United States — had reached North America, transported by ships in the thousands. Rather than being a food source, it's most likely that the birds were brought across from Europe to satiate the growing pigeon-breeding trend among hobbyists, said Michael Habib, a paleontologist in the Dinosaur Institute at the Los Angeles County Museum of Natural History, and the University of Southern California.

Inevitably, birds escaped captivity, and began to breed freely in American cities. "We created this novel [urban] habitat and then we basically engineered an animal that does very well in that novel habitat," Habib told Live Science. "They were successful in cities because we engineered them to be comfortable living around humans." [Do Birds Really Abandon Their Chicks If Humans Touch Them?]

Cities became the perfect backdrop for the pioneering pigeons' success. "Pigeons are naturally cliff-dwellers and tall buildings do a pretty great job at mimicking cliffs," Carlen told Live Science. "Ornate facing, window sills and air-conditioning units provide fantastic perches for pigeons, similar to the crevices found on the side of a cliff."

Another trait that makes pigeons more adaptable is their appetite. While other bird species have to rely on supplies of berries, seeds and insects, pigeons can eat just about anything that humans toss in the trash. "Other species are specialists and pigeons are the ultimate generalists," Portugal said. "And the food is endless: I don't think too many pigeons go to bed hungry!"

The pigeon's unusual breeding biology seals the deal: Both parents rear their chicks on a diet of special protein- and fat-rich milk produced in a throat pouch called the crop. So, instead of having to rely on insects, worms and seeds to keep their young alive — resources that would be scarcer in cities — pigeons can provide for their offspring no matter what, Portugal says: "As long as the adults can eat, they can feed their babies, too."

All these traits give pigeons a competitive edge compared with other species that might attempt survival in cities. Combined with the pigeon's prolific breeding habits (parents can produce up to 10 chicks a year), it's easy to see why these birds have become so populous around the world.

Not everyone appreciates the urban phenomenon that these birds have become — hence the "rat with wings" moniker. That's understandable to some extent: Pigeons can spread diseases, and the mounds of guano they splatter across buildings can be cumbersome and costly to clean.

Despite this, Portugal sees a benefit to their presence in our urban environments. "They're actually one of the few bits of wildlife that people get to interact with in cities now," he said. What's more, "they're super-adaptable and super-successful they're the ultimate survivors. Actually, we can learn a lot from them."

Why isn't there any naturally occurring blue food?

Question: Why isn’t there any naturally occurring blue food?

Answer: The answer to your question involves some pretty complex chemistry, so I’m going to give just an overview. The color in plant foods comes from natural pigments. In general, chlorophyll provides green and blue-green carotenoids provide orange, yellow, red and red-orange and anthocyanins provide red, purple and various shades of blue. Individual pigments can differ considerably. One reason that there are so few naturally blue foods is that a combination of pigments is usually present in any given fruit or vegetable. Blue anthocyanins are chemically less stable than other pigments and are usually dominated by them. In order for the blue hue to predominate in the mix, it must have a slight shift in its chemical makeup. This is a rare occurrence. In the case of concord grapes, the mixture of anthocyanin pigments and the chemistry favors the blue hue. In other words, the blue pigment is there, the chemistry is right and you get a predominantly blue hue.

I’ve heard this since I was a little kid. And I have never found one study showing it to be true. The idea isn’t without merit eggs contain lots of protein, fat, and vitamins, all essential to hair growth and skin health. One of those vitamins is biotin, which is important for cell growth and fatty-acid metabolism. Biotin is widely accepted to be helpful for human hair, though that may be simply because deficiencies can cause hair loss. While egg whites contain avidin, a biotin inhibitor, the yolks contain enough biotin to make up for it. But diets high in fat have been shown to result in glossier and softer coats in dogs, and might do the coat more good than eggs would.

As for feeding them raw, it’s true that cooking will do away with the avidin, but some people feel it also destroys vitamins. And of course, the raw egg/salmonella debate rages, with most food authorities cautioning against feeding eggs raw and many dog naturalists advocating it, pointing out that the coyote that raised the chicken coop didn’t bother to cook them. And, I assume, had a shiny coat.

The bottom line is an egg is a good source of protein and other nutrients, but probably no better than any good diet at promoting a shiny coat.


Water molecules move randomly around each other.

The oxygen atom has a negative charge.

All BUT ONE of these compounds dissolve in water. They are

zygote → stem cells → cell differentiation

zygote → cell differentiation → mitosis

stem cells → zygote → cell differentiation

to build a molecule of mRNA

to produce a start sequence

to switch uracil with thymine on the exposed gene

- Evolution occurs in a population when there is a change in the genetic makeup of the population over a period of time.

- Evolution occurs in a population when its genetic makeup changes over time.

- For evolution to occur, there must be variation in a population.

- Mutation, migration, genetic drift, recombination, and natural selection all play a role in evolution.

- Charles Darwin was influenced by many other scientists as he developed the theory of evolution by natural selection.

- Like the study of science itself, the study of evolution has a history based on past discoveries.

- Darwin was influenced by and built on the work of many other scholars as he developed his theory of evolution.

- As you read through the lesson online, use the space below to take notes.
Adaptations are characteristics that help organisms survive in their environment.

- The characteristics you see in the organisms around you are adaptations.

- Adaptations are traits that help an organism survive and reproduce in its environment.

- Many structures in living organisms are adaptations that help those organisms carry out particular functions.

- Many unrelated organisms have similar adaptations that carry out similar functions.

- Environment shapes the needs of organisms, and similar environments lead to similar adaptations.

Why aren’t there more women in science? The industry structure is sexist

W hy are so few women publishing scientific papers? It is a question that has been posed by New Scientist magazine, as it reports that in medicine, female authorship of scientific papers has started to go backwards. Since 2009, the proportion of women as lead authors has gone down.

Findings such as these usually provoke a cry of “We need more women in science!” and organisations wheel out a spokesperson to explain that girls should be encouraged to study science at university. The Welsh government, for example, celebrated International Women’s Day this way.

But while this is a fantastic way to persuade science funding bodies to reach into their pockets, it just doesn’t fit with the evidence. The quiet truth is this: women are doing science. And not only “more women than ever before”, as the New Scientist puts it. In fact, in lots of scientific disciplines women outnumber men.

Don’t believe me? Recent data from the UK’s Higher Education Statistics Agency (although not available online, I requested the gender breakdown from its press office) shows that 69% of students studying medical technology-related degrees are women, as are 86% of those studying degrees in polymers. A whopping 77% of students studying veterinary science are female. The figure for psychology is even higher at 79%. The majority of students studying degrees in anthropology (72%) ophthalmics (69%) anatomy, physiology and pathology (64%) zoology (63%) forensic and archaeological sciences (61%) and pharmacology, toxicology and pharmacy (61%) are female.

More women than men study clinical dentistry (59%) clinical medicine (55%) biology (58%) molecular biology, biophysics and biochemistry (54%) archaeology (56%) and “agriculture and related subjects” (67%). The story is the same in subjects such as genetics (57%) and microbiology (56%). For programmes classed as “broadly based programmes in medicine and dentistry”, the percentage of female students is even higher, at 76%. There may be more women studying full-time degrees across the board (54%), but there is still an undeniably strong female bias in science subjects.

If there are so many women studying medical subjects, how do we explain the sudden decline in female authorship in medical journals since 2009?

This is unlikely to be simply about the number of women studying medicine. Women have accounted for more than half of all new medical students since the 1990s. Today, even at postgraduate level, 64% of students studying medical and dentistry subjects are female.

Instead of discussing gender bias, the New Scientist blames the “choice” to have a family. It points to a study in this month’s American Economic Review that shows women incurring earnings penalties in science if they have children. A recent House of Commons science and technology committee report goes into more detail, saying that scientific research careers are dominated by short-term contracts with poor job security – at the very time of life that women need to have children (if they want them). The female postdoctoral scientist faces difficult decisions while stuck on fixed-term contracts before tenure, with very little in the way of institutional support. Women should not have to choose between career and family, says the science magazine. But surely male scientists face similar choices?

‘In lots of scientific disciplines, women outnumber men.’ Photograph: DCPhoto/Alamy

Apparently not. European social science research shows that male and female scientists often have different types of partners: male scientists more frequently have a stay-at-home partner looking after the children, while female scientists are more likely to have another scientist as a spouse. So male scientists might not need family-friendly working practices to have a successful career but female scientists do. Hence the loss of women in the “leaky pipeline” of scientific careers. And that is to say nothing of the research that found scientists perceived job applicants to be less competent when they had female names.

Does this matter? It does. Male-dominated science and technology allowed women to be killed by first-generation car airbags at speeds of only 20mph, because engineers did not foresee that breasts close to the wheel could push airbags up towards the neck. And as Naomi Wolf pointed out in her book Promiscuities: A Secret History of Female Desire, over the centuries anatomists forgot about and “re-discovered” the clitoris at least six times before the scientist Helen O’Connell stepped in.

Small wonder, then, that the Commons science and technology committee argues that the usual emphasis on inspiring girls to go into science careers is not enough, saying: “Efforts are wasted if women are subsequently disproportionately disadvantaged in scientific careers compared to men.”

And yet still we are told we need to inspire more girls. Lobbying groups are much more vocal about the need to recruit women into science than they are about what needs to be done to retain females in science after graduation.

A rare article in this month’s issue of the journal Science might explain why. After detailing shocking examples of discrimination and misogyny – from inappropriate discussions about rape and the female anatomy to colleagues’ failure to acknowledge female expertise, the author writes: “It may be too much to ask women in science organisations to change misogynist culture in a world that remains misogynistic.”

Sure, initiatives such as Soapbox Science at London’s Southbank Centre this week are valuable for widening people’s ideas of who scientists can be. But the sad fact is it is much easier to say “we need more women in science” than it is to stand up, look the (mostly male) leaders in science and politicians in the eye and say: “Your laboratories, hiring procedures, grant-allocating processes and publishing routines are all sexist, and this results in science and technologies that aren’t good for at least half the population. Why have you allowed this to continue for so long?”

Low-fat and fat-free foods

Among the various foibles of decades past — including gems like mullets, polyester leisure suits, and eyebrows plucked within a millimeter of their existence — lies the idea that low-fat and fat-free foods are super healthy. As it turns out, the nutrition mantra of the '90s was totally wrong.

According to CBS News, a Tufts University study showed that "people who consumed full-fat dairy products had as much as a 46 percent lower risk of developing diabetes" compared to people who ate low-fat and non-fat dairy. A second study, which tracked both diet and the incidence of mortality and major cardiac events among people in 18 countries, found that "high carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality."

So why are reduced and non-fat products on the outs? It largely boils down to taste (pun intended). According to WebMD, low-fat and fat-free foods often lose flavor when the fat is extracted. So, to compensate for the lack of flavor, "food makers tend to pour other ingredients — especially sugar, flour, thickeners, and salt — into the products. That can add calories." In fact, research has shown that higher fat foods tend to be more satiating than lower fat foods and can lead to greater weight loss than high-carb/low-fat diets. So, while it doesn't give us all license to slather everything in butter, we definitely shouldn't fear fat.

What is Happening to the Gulf’s Blue Crabs?

Blue crabs are one of nature’s survivors. This tough little creature—whose scientific name Callinectes sapidus translates to “savory beautiful swimmer”—is a critical part of the Gulf’s food chain, eaten by a wide variety of species from the Kemp’s ridley sea turtle to the whooping crane to many, many different kinds of fish.

The blue crab’s critical place in the Gulf’s food web means a prolonged drop in its populations could have widespread repercussions.

A juvenile blue crab is held near its nursery habitat. Photo: ChesapeakeBayEO.

Tiny creatures might take in such low amounts of oil that they could survive, [Bob Thomas, a biologist at Loyola University in New Orleans] said. But those at the top of the chain, such as dolphins and tuna, could get fatal “megadoses.”

In the three years since the well was capped, crab populations have not seen a precipitous drop until recently, but dolphins have been dying in unprecedented numbers.

For blue crabs, 2012 was overall an average year in Louisiana, but the picture was mixed, with some places seeing declines while others saw an increase. This is not unusual. Crab populations fluctuate widely–the species is very responsive to changes in its environment, such as unfavorable weather patterns or lack of fresh water flowing into its favored habitats during droughts.

But now, particularly in Louisiana’s Lake Pontchartrain, scientists and fishermen are worried. The Houma Today reports:

“There are absolutely no crabs,” said Keith Watts, Crab Task Force representative for the Louisiana Seafood Promotion and Marketing Board. “We’re not catching anything. It’s ridiculous.”

Watts does most of his crabbing in Lake Pontchartrain in New Orleans, but he reported that the same holds true throughout the rest of the state.

Crabbers in Mississippi, Alabama and Florida are also complaining that catches have been down in 2013.

Does this drop in populations have anything to do with Deepwater Horizon? John Lopez, coastal sustainability program director of the Lake Pontchartrain Basin Foundation, is questioning whether the Gulf oil disaster could be the source of the problem. As stated in the Times Picayune:

“The crabs lay their eggs out in the Gulf of Mexico, and it takes about three years for those crabs to mature, so if you think about it, we’re now three years after the oil spill, and if there was an impact to the eggs — if they were damaged out in the Gulf three years ago — it could be manifested just now because this is the time those eggs would be mature crabs,” Lopez said.

Other scientists are reporting harmful lesions and visible infections on blue crab. According to the Tampa Bay Times:

Darryl Felder, a University of Louisiana biology professor, has been studying deep-water shrimp and lobsters as well as crabs caught in Louisiana’s Barataria Bay, which was inundated with oil. He said the deformities originally found on the shrimp and lobsters have eased up, but not on crabs.

“People are bringing in (crabs) that are really messed up,” he said. “The crab catches are really down, and what they’re getting have big lesions on them — lesions and fungal or bacterial infections.”

The problem, he said, is that no one was documenting these species before the disaster, so it’s hard to say whether this is normal or was caused by the oil.

Aside from their ecological importance, blue crabs are one of the most economically important fisheries of the Gulf. Louisiana alone lands approximately 26 percent of the total blue crabs for the nation, a value of more than $135 million at today’s market prices.

A pair of mature blue crabs. Photo: chesbayprogram.

According to a recent report on wildlife tourism in the Gulf by Datu Research over 1,100 outfitters and 11,000 lodging and dining establishments generate business for one another.

So who is getting to the bottom of this? The questions raised by the decline in blue crab numbers and the observed lesions and infections call for serious scientific inquiry.

Whatever the cause of the current decline, we can and should take steps to restore habitat for blue crabs. This “savory beautiful swimmer” that is so important to so many species of wildlife relies on estuaries—places where freshwater from rivers flows into the saltier waters of the Gulf—to feed and reproduce.

But across the Gulf Coast, our estuaries and wetlands are in serious decline. The Gulf loses 20,000 acres of coastal wetlands every single year.

Using the money from BP’s oil spill fines to stop coastal wetlands loss and protect habitats for blue crabs will have a positive impact on the entire food web of the Gulf of Mexico—and the Gulf Coast economy as well.

Why Are There Still So Few Women in Science?

Last summer, researchers at Yale published a study proving that physicists, chemists and biologists are likely to view a young male scientist more favorably than a woman with the same qualifications. Presented with identical summaries of the accomplishments of two imaginary applicants, professors at six major research institutions were significantly more willing to offer the man a job. If they did hire the woman, they set her salary, on average, nearly $4,000 lower than the man’s. Surprisingly, female scientists were as biased as their male counterparts.

The new study goes a long way toward providing hard evidence of a continuing bias against women in the sciences. Only one-fifth of physics Ph.D.’s in this country are awarded to women, and only about half of those women are American of all the physics professors in the United States, only 14 percent are women. The numbers of black and Hispanic scientists are even lower in a typical year, 13 African-Americans and 20 Latinos of either sex receive Ph.D.’s in physics. The reasons for those shortages are hardly mysterious — many minority students attend secondary schools that leave them too far behind to catch up in science, and the effects of prejudice at every stage of their education are well documented. But what could still be keeping women out of the STEM fields (“STEM” being the current shorthand for “science, technology, engineering and mathematics”), which offer so much in the way of job prospects, prestige, intellectual stimulation and income?

As one of the first two women to earn a bachelor of science degree in physics from Yale — I graduated in 1978 — this question concerns me deeply. I attended a rural public school whose few accelerated courses in physics and calculus I wasn’t allowed to take because, as my principal put it, “girls never go on in science and math.” Angry and bored, I began reading about space and time and teaching myself calculus from a book. When I arrived at Yale, I was woefully unprepared. The boys in my introductory physics class, who had taken far more rigorous math and science classes in high school, yawned as our professor sped through the material, while I grew panicked at how little I understood. The only woman in the room, I debated whether to raise my hand and expose myself to ridicule, thereby losing track of the lecture and falling further behind.

In the end, I graduated summa cum laude, Phi Beta Kappa, with honors in the major, having excelled in the department’s three-term sequence in quantum mechanics and a graduate course in gravitational physics, all while teaching myself to program Yale’s mainframe computer. But I didn’t go into physics as a career. At the end of four years, I was exhausted by all the lonely hours I spent catching up to my classmates, hiding my insecurities, struggling to do my problem sets while the boys worked in teams to finish theirs. I was tired of dressing one way to be taken seriously as a scientist while dressing another to feel feminine. And while some of the men I wanted to date weren’t put off by my major, many of them were.

Mostly, though, I didn’t go on in physics because not a single professor — not even the adviser who supervised my senior thesis — encouraged me to go to graduate school. Certain this meant I wasn’t talented enough to succeed in physics, I left the rough draft of my senior thesis outside my adviser’s door and slunk away in shame. Pained by the dream I had failed to achieve, I locked my textbooks, lab reports and problem sets in my father’s army footlocker and turned my back on physics and math forever.

Not until 2005, when Lawrence Summers, then president of Harvard, wondered aloud at a lunchtime talk why more women don’t end up holding tenured positions in the hard sciences, did I feel compelled to reopen that footlocker. I have known Summers since my teens, when he judged my high-school debate team, and he has always struck me as an admirer of smart women. When he suggested — among several other pertinent reasons — that innate disparities in scientific and mathematical aptitude at the very highest end of the spectrum might account for the paucity of tenured female faculty, I got the sense that he had asked the question because he genuinely cared about the answer. I was taken aback by his suggestion that the problem might have something to do with biological inequalities between the sexes, but as I read the heated responses to his comments, I realized that even I wasn’t sure why so many women were still giving up on physics and math before completing advanced degrees. I decided to look up my former classmates and professors, review the research on women’s performance in STEM fields and return to Yale to see what, if anything, had changed since I studied there. I wanted to understand why I had walked away from my dream, and why so many other women still walk away from theirs.

In many ways, of course, the climate has become more welcoming to young women who want to study science and math. Female students at the high school I attended in upstate New York no longer need to teach themselves calculus from a book, and the physics classes are taught by a charismatic young woman. When I first returned to Yale in the fall of 2010, everyone kept boasting that 30 to 40 percent of the undergraduates majoring in physics and physics-related fields were women. More remarkable, those young women studied in a department whose chairwoman was the formidable astrophysicist Meg Urry, who earned her Ph.D. from Johns Hopkins, completed a postdoctorate at M.I.T.’s center for space research and served on the faculty of the Hubble space telescope before Yale hired her as a full professor in 2001. (At the time, there wasn’t a single other female faculty member in the department.)

In recent years, Urry has become devoted to using hard data and anecdotes from her own experience to alter her colleagues’ perceptions as to why there are so few women in the sciences. In response to the Summers controversy, she published an essay in The Washington Post describing her gradual realization that women were leaving the profession not because they weren’t gifted but because of the “slow drumbeat of being underappreciated, feeling uncomfortable and encountering roadblocks along the path to success.”

Although Urry confessed in her op-ed column that as a young scientist she interpreted her repeated failures to be hired or promoted as proof that she wasn’t good enough, anyone who meets her now would have a hard time seeing her as lacking in confidence. She has a quizzical smile and radiant eyes and an irreverent sense of humor not one but five people described her to me as the busiest woman on campus.

Before we met, Urry predicted that the female students in her department would recognize the struggles she and I had faced but that their support system protected them from the same kind of self-doubt. For instance, under the direction of Bonnie Fleming, the second woman to gain tenure in the physics department at Yale, the students sponsor a semiregular Conference for Undergraduate Women in Physics at Yale. Beyond that, Urry suggested that with so many women studying physics at Yale, and so many of them at the top of their class, the faculty couldn’t help recognizing that their abilities didn’t differ from the men’s. When I mentioned that a tea was being held that afternoon so I could interview female students interested in science and gender, Urry said she would try to attend.

Judith Krauss, the professor who was hosting the tea (she is the former dean of nursing and now master of Silliman College, where I lived as an undergraduate), warned me that very few students would be interested enough to show up. When 80 young women (and three curious men) crowded into the room, Krauss and I were stunned. By the time Urry hurried in, she was lucky to find a seat.

The students clamored to share their stories. One young woman had been disconcerted to find herself one of only three girls in her AP physics course in high school, and even more so when the other two dropped out. Another student was the only girl in her AP physics class from the start. Her classmates teased her mercilessly: “You’re a girl. Girls can’t do physics.” She expected the teacher to put an end to the teasing, but he didn’t.

Other women chimed in to say that their teachers were the ones who teased them the most. In one physics class, the teacher announced that the boys would be graded on the “boy curve,” while the one girl would be graded on the “girl curve” when asked why, the teacher explained that he couldn’t reasonably expect a girl to compete in physics on equal terms with boys.

The only members of the audience who didn’t know what the rest were talking about were the women who had attended all-girls secondary schools or had grown up in foreign countries. (The lesbian scientists with whom I spoke, at the tea and elsewhere, reported differing reactions to the gender dynamic of the classroom and the lab, but voiced many of the same concerns as the straight women.) One student — I took her to be Indian or Pakistani — said she arrived on campus having taken lots of advanced classes and didn’t hesitate to sign up for the most rigorous math course. Shaken to find herself the only girl in the class, unable to follow the first lecture, she asked the professor: Should I be here? “If you’re not confident that you should be here” — she imitated his scorn — “you shouldn’t take the class.”

After the tea, a dozen girls stayed to talk. “The boys in my group don’t take anything I say seriously,” one astrophysics major complained. “I hate to be aggressive. Is that what it takes? I wasn’t brought up that way. Will I have to be this aggressive in graduate school? For the rest of my life?” Another said she disliked when she and her sister went out to a club and her sister introduced her as an astrophysics major. “I kick her under the table. I hate when people in a bar or at a party find out I’m majoring in physics. The minute they find out, I can see the guys turn away.” Yet another went on about how even at Yale the men didn’t want to date a physics major, and how she was worried she’d go through four years there without a date.

After the students left, I asked Urry if she was as flabbergasted as I was. “More,” she said — after all, she was the chairwoman of the department in which most of these girls were studying.

In the two years that followed, I heard similar accounts echoed among young women in Michigan, upstate New York and Connecticut. I was dismayed to find that the cultural and psychological factors that I experienced in the ’70s not only persist but also seem all the more pernicious in a society in which women are told that nothing is preventing them from succeeding in any field. If anything, the pressures to be conventionally feminine seem even more intense now than when I was young.

For proof of the stereotypes that continue to shape American attitudes about science, and about women in science in particular, you need only watch an episode of the popular television show “The Big Bang Theory,” about a group of awkward but endearing male Caltech physicists and their neighbor, Penny, an attractive blonde who has moved to L.A. to make it as an actress. Although two of the scientists on the show are women, one, Bernadette, speaks in a voice so shrill it could shatter a test tube. When she was working her way toward a Ph.D. in microbiology, rather than working in a lab, as any real doctoral student would do, she waitressed with Penny. Mayim Bialik, the actress who plays Amy, a neurobiologist who becomes semiromantically involved with the childlike but brilliant physicist Sheldon, really does have a Ph.D. in neuroscience and is in no way the hideously dumpy woman she is presented as on the show. “The Big Bang Theory” is a sitcom, of course, and therefore every character is a caricature, but what remotely normal young person would want to enter a field populated by misfits like Sheldon, Howard and Raj? And what remotely normal young woman would want to imagine herself as dowdy, socially clueless Amy rather than as stylish, bouncy, math-and-science-illiterate Penny?

Although Americans take for granted that scientists are geeks, in other cultures a gift for math is often seen as demonstrating that a person is intuitive and creative. In 2008, the American Mathematical Society published data from a number of prestigious international competitions in an effort to track standout performers. The American competitors were almost always the children of immigrants, and very rarely female. For example, between 1959 and 2008, Bulgaria sent 21 girls to the International Mathematical Olympiad, while the U.S., from 1974, when it first entered the competition, to 2008, sent only 3 no woman even made the American team until 1998. According to the study’s authors, native-born American students of both sexes steer clear of math clubs and competitions because “only Asians and nerds” would voluntarily do math. “In other words, it is deemed uncool within the social context of U.S.A. middle and high schools to do mathematics for fun doing so can lead to social ostracism. Consequently, gifted girls, even more so than boys, usually camouflage their mathematical talent to fit in well with their peers.”


The study’s findings apply equally in science. Urry told me that at the space telescope institute where she used to work, the women from Italy and France “dress very well, what Americans would call revealing. You’ll see a Frenchwoman in a short skirt and fishnets that’s normal for them. The men in those countries seem able to keep someone’s sexual identity separate from her scientific identity. American men can’t seem to appreciate a woman as a woman and as a scientist it’s one or the other.”

That the disparity between men and women’s representation in science and math arises from culture rather than genetics seems beyond dispute. In the early 1980s, a large group of American middle-schoolers were given the SAT exam in math among those who scored higher than 700, boys outperformed girls by 13 to 1. But scoring 700 or higher on the SATs, even in middle school, doesn’t necessarily reveal true mathematical creativity or facility with higher-level concepts. And these were all American students. The mathematical society’s study of the top achievers in international competitions went much further in examining genius by analyzing the performance of young women in other cultures. The study’s conclusion? The scarcity of women at the very highest echelons “is due, in significant part, to changeable factors that vary with time, country and ethnic group. First and foremost, some countries identify and nurture females with very high ability in mathematics at a much higher frequency than do others.” Besides, the ratio of boys to girls scoring 700 or higher on the math SAT in middle school is now only three to one. If girls were so constrained by their biology, how could their scores have risen so steadily in such a short time?

In elementary school, girls and boys perform equally well in math and science. But by the time they reach high school, when those subjects begin to seem more difficult to students of both sexes, the numbers diverge. Although the percentage of girls among all students taking high-school physics rose to 47 percent in 1997 from about 39 percent in 1987, that figure has remained constant into the new millennium. And the numbers become more alarming when you look at AP classes rather than general physics, and at the scores on AP exams rather than mere attendance in AP classes. The statistics tend to be a bit more encouraging in AP calculus, but they are far worse in computer science. Maybe boys care more about physics and computer science than girls do. But an equally plausible explanation is that boys are encouraged to tough out difficult courses in unpopular subjects, while girls, no matter how smart, receive fewer arguments from their parents, teachers or guidance counselors if they drop a physics class or shrug off an AP exam.

That cultural signals can affect a student’s ability to perform on an exam has long been known. In a frequently cited 1999 study, a sample of University of Michigan students with similarly strong backgrounds and abilities in math were divided into two groups. In the first, the students were told that men perform better on math tests than women in the second, the students were assured that despite what they might have heard, there was no difference between male and female performance. Both groups were given a math test. In the first, the men outscored the women by 20 points in the second, the men scored only 2 points higher.

It’s even possible that gifts in science and math aren’t identifiable by scores on tests. Less than one-third of the white American males who populate the ranks of engineering, computer science, math and the physical sciences scored higher than 650 on their math SATs, and more than one-third scored below 550. In the middle ranks, hard work, determination and encouragement seem to be as important as raw talent. Even at the very highest levels, test scores might be irrelevant apparently, Richard Feynman’s I.Q. was a less-than-remarkable 125.

The most powerful determinant of whether a woman goes on in science might be whether anyone encourages her to go on. My freshman year at Yale, I earned a 32 on my first physics midterm. My parents urged me to switch majors. All they wanted was that I be able to earn a living until I married a man who could support me, and physics seemed unlikely to accomplish either goal.

I trudged up Science Hill to ask my professor, Michael Zeller, to sign my withdrawal slip. I took the elevator to Professor Zeller’s floor, then navigated corridors lined with photos of the all-male faculty and notices for lectures whose titles struck me as incomprehensible. I knocked at my professor’s door and managed to stammer that I had gotten a 32 on the midterm and needed him to sign my drop slip.

“Why?” he asked. He received D’s in two of his physics courses. Not on the midterms — in the courses. The story sounded like something a nice professor would invent to make his least talented student feel less dumb. In his case, the D’s clearly were aberrations. In my case, the 32 signified that I wasn’t any good at physics.

“Just swim in your own lane,” he said. Seeing my confusion, he told me that he had been on the swimming team at Stanford. His stroke was as good as anyone’s. But he kept coming in second. “Zeller,” the coach said, “your problem is you keep looking around to see how the other guys are doing. Keep your eyes on your own lane, swim your fastest and you’ll win.”

I gathered this meant he wouldn’t be signing my drop slip.

“You can do it,” he said. “Stick it out.”

I stayed in the course. Week after week, I struggled to do my problem sets, until they no longer seemed impenetrable. The deeper I now tunnel into my four-inch-thick freshman physics textbook, the more equations I find festooned with comet-like exclamation points and theorems whose beauty I noted with exploding novas of hot-pink asterisks. The markings in the book return me to a time when, sitting in my cramped dorm room, I suddenly grasped some principle that governs the way objects interact, whether here on earth or light years distant, and I marveled that such vastness and complexity could be reducible to the equation I had highlighted in my book. Could anything have been more thrilling than comprehending an entirely new way of seeing, a reality more real than the real itself?

I earned a B in the course the next semester I got an A. By the start of my senior year, I was at the top of my class, with the most experience conducting research. But not a single professor asked me if I was going on to graduate school. When I mentioned shyly to Professor Zeller that my dream was to apply to Princeton and become a theoretician, he shook his head and said that if you went to Princeton, you had better put your ego in your back pocket, because those guys were so brilliant and competitive that you would get that ego crushed, which made me feel as if I weren’t brilliant or competitive enough to apply.

Not even the math professor who supervised my senior thesis urged me to go on for a Ph.D. I had spent nine months missing parties, skipping dinners and losing sleep, trying to figure out why waves — of sound, of light, of anything — travel in a spherical shell, like the skin of a balloon, in any odd-dimensional space, but like a solid bowling ball in any space of even dimension. When at last I found the answer, I knocked triumphantly at my adviser’s door. Yet I don’t remember him praising me in any way. I was dying to ask if my ability to solve the problem meant that I was good enough to make it as a theoretical physicist. But I knew that if I needed to ask, I wasn’t.

Years later, when I contacted that same professor, the mathematician Roger Howe, he responded enthusiastically to my request that we get together to discuss women in science and math. We met at his office, in a building that still has a large poster of famous mathematicians (all male) in the lobby, although someone has tacked a smaller poster of “famous women in math” on the top floor beside the women’s bathroom. Howe appeared remarkably youthful, even when you consider that when I studied with him, he was the youngest full professor at Yale. He suggested we grab a sandwich, and as we sat waiting for our panini, I told him that one reason I didn’t go to graduate school was that I compared myself with him and judged my talents wanting. After all, I’d had such a difficult time solving the problem he had challenged me to solve.

He looked puzzled. “But you solved it.”

“Yeah,” I said. “At the end I really understood what I was doing. But it took me such a long time.”

“But that’s just how it is,” he said. “You don’t see it until you do, and then you wonder why you didn’t see it all along.”

But I had needed to drop my class in real analysis.

Howe shrugged. There are a lot of different math personalities. Different mathematicians are good at different fields.

I asked if he had noticed any differences between the ways male and female students approach math problems, whether they have different “math personalities.” No, he said. Then again, he couldn’t get inside his students’ heads. He did have two female students go on in math, and both had done fairly well.

I asked why even now there were no female professors on Yale’s math faculty. No tenured women, Howe corrected me. In 2010, the department voted to hire a woman for a tenure-track job. (That woman has yet to come up for tenure, but this year the faculty did hire a senior female professor.) Well, I said, that’s still not very many. He stared into the distance. “I guess I just haven’t seen that many women whose work I’m excited about.” I watched him mull over his answer, the way I used to watch him visualize n-dimensional toruses cradled in his hands. “Maybe women are victims of misperception,” he said finally. Not long ago, one of his colleagues at another school admitted to him that back when all of them were starting out, there were two people in his field, a woman and a man, and this colleague assumed the man must be the better mathematician, but the woman has gone on to do better work.

I finally came straight out and asked what he thought of my project. How did it compare with all the other undergraduate research projects he must have supervised?

His eyebrows lifted, as if to express the mathematical symbol for puzzlement. Actually, he hadn’t supervised more than two or three undergraduates in his entire career. “It’s very unusual for any undergraduate to do an independent project in mathematics,” he said. “By that measure, I would have to say that what you did was exceptional.”

“Exceptional?” I echoed. Then why had he never told me?

The question took him aback. I asked if he ever specifically encouraged any undergraduates to go on for Ph.D.’s after all, he was now the director of undergraduate studies. But he said he never encouraged anyone to go on in math. “It’s a very hard life,” he told me. “You need to enjoy it. There’s a lot of pressure being a mathematician. The life, the culture, it’s very hard.”

When I told Meg Urry that Howe and several other of my professors said they don’t encourage anyone to go on in physics or math because it’s such a hard life, she blew raspberries. “Oh, come on,” she said. “They’re their own bosses. They’re well paid. They love what they do. Why not encourage other people to go on in what you love?” She gives many alumni talks, “and there’s always a woman who comes up to me and says the same thing you said, I wanted to become a physicist, but no one encouraged me. If even one person had said, ‘You can do this.’ ” She laughed. “Women need more positive reinforcement, and men need more negative reinforcement. Men wildly overestimate their learning abilities, their earning abilities. Women say, ‘Oh, I’m not good, I won’t earn much, whatever you want to give me is O.K.’ ”

One student told Urry she doubted that she was good enough for grad school, and Urry asked why — the student had earned nearly all A’s at Yale, which has one of the most rigorous physics programs in the country. “A woman like that didn’t think she was qualified, whereas I’ve written lots of letters for men with B averages.” She won’t say that getting a Ph.D. is easy. “It is a grind. When a young woman says, ‘How is this going to be for me?’ I have to say that yes, there are easier things to do. But that doesn’t mean I need to discourage her from trying. You don’t need to be a genius to do what I do. When I told my adviser what I wanted to do, he said, ‘Oh, Meg, you have to be a genius to be an astrophysicist.’ I was the best physics major they had. What he was really saying was that I wasn’t a genius, wasn’t good enough. What, all those theoreticians out there are all Feynman or Einstein? I don’t think so.”

Not long ago, I met five young Yale alumnae at a Vietnamese restaurant in Cambridge. Three of the women were attending graduate school at Harvard — two in physics and one in astronomy — and two were studying oceanography at M.I.T. None expressed anxiety about surviving graduate school, but all five said they frequently worried about how they would teach and conduct research once they had children.

“That’s where you lose all the female physicists,” one woman said.

“Yeah, it’s even hard to get your kid into child care at M.I.T.,” said another.

“Women are just as willing as men to sacrifice other things for work,” said a third. “But we’re not willing to do even more work than the men — work in the lab and teach, plus do all the child care and housework.”

What most young women don’t realize, Urry said, is that being an academic provides a female scientist with more flexibility than most other professions. She met her husband on her first day at the Goddard Space Flight Center. “And we have a completely equal relationship,” she told me. “When he looks after the kids, he doesn’t say he’s helping me.” No one is claiming that juggling a career in physics while raising children is easy. But having a family while establishing a career as a doctor or a lawyer isn’t exactly easy either, and that doesn’t prevent women from pursuing those callings. Urry suspects that raising a family is often the excuse women use when they leave science, when in fact they have been discouraged to the point of giving up.

All Ph.D.’s face the long slog of competing for a junior position, writing grants and conducting enough research to earn tenure. Yet women running the tenure race must leap hurdles that are higher than those facing their male competitors, often without realizing any such disparity exists.

In the mid-1990s, three senior female professors at M.I.T. came to suspect that their careers had been hampered by similar patterns of marginalization. They took the matter to the dean, who appointed a committee of six senior women and three senior men to investigate their concerns. After performing the investigation and studying the data, the committee concluded that the marginalization experienced by female scientists at M.I.T. “was often accompanied by differences in salary, space, awards, resources and response to outside offers between men and women faculty, with women receiving less despite professional accomplishments equal to those of their colleagues.” The dean concurred with the committee’s findings. And yet, as was noted in the committee’s report, his fellow administrators “resisted the notion that there was any problem that arose from gender bias in the treatment of the women faculty. Some argued that it was the masculine culture of M.I.T. that was to blame, and little could be done to change that.” In other words, women didn’t become scientists because science — and scientists — were male.

The committee’s most resonant finding was that the discrimination facing female scientists in the final quarter of the 20th century was qualitatively different from the more obvious forms of sexism addressed by civil rights laws and affirmative action, but no less real. As Nancy Hopkins, one of the professors who initiated the study, put it in an online forum: “I have found that even when women win the Nobel Prize, someone is bound to tell me they did not deserve it, or the discovery was really made by a man, or the important result was made by a man, or the woman really isn’t that smart. This is what discrimination looks like in 2011.”

Not everyone agrees that what was uncovered at M.I.T. actually qualifies as discrimination. Judith Kleinfeld, a professor emeritus in the psychology department at the University of Alaska, argues that the M.I.T. study isn’t persuasive because the number of faculty members involved is too small and university officials refuse to release the data. Even if female professors have been shortchanged or shunted aside, their marginalization might be a result of the same sorts of departmental infighting, personality conflicts and “mistaken impressions” that cause male faculty members to feel slighted as well. “Perceptions of discrimination are evidence of nothing but subjective feelings,” Kleinfeld scoffs.

But broader studies show that the perception of discrimination is often accompanied by a very real difference in the allotment of resources. In February 2012, the American Institute of Physics published a survey of 15,000 male and female physicists across 130 countries. In almost all cultures, the female scientists received less financing, lab space, office support and grants for equipment and travel, even after the researchers controlled for differences other than sex. “In fact,” the researchers concluded, “women physicists could be the majority in some hypothetical future yet still find their careers experience problems that stem from often unconscious bias.”

Jo Handelsman spends much of her time studying micro-organisms in the soil and the guts of insects, but since the early 1990s, she also has devoted herself to increasing the participation of women and minorities in science. Although she long suspected that the same subtle biases documented in the general population were at work among scientists, she had no data to support such assertions. “People said, ‘Oh, that might happen in the Midwest or in the South, but not in New England, or not in my department — we just graduated a woman.’ They would say, ‘That only happens in economics.’ ” Male scientists told Handelsman: I have women in my lab! My female students are smarter than the men! “They go to their experience,” she said, “with a sample size of one.” She laughed. “Scientists can be so unscientific.”

In 2010, Handelsman teamed up with Corinne Moss-Racusin, then a postdoctoral associate at Yale, to begin work on the study that was published last year, which directly documented gender bias in American faculty members in three scientific fields — physics, chemistry and biology — at six major research institutions scattered across the country.

Moss-Racusin, along with collaborators in the departments of psychology, psychiatry and the School of Management, designed a study that involved sending out identical résumés to professors of both sexes, with a cover page stating that the young applicant had recently obtained a bachelor’s degree and was now seeking a position as a lab manager. Half of the 127 participants received a résumé for a student named John the other half received the identical résumé for Jennifer. In both cases, the applicant’s qualifications were sufficient for the job (with supportive letters of recommendation and the coauthorship of a journal article) but not overwhelmingly persuasive — the applicant’s G.P.A. was only 3.2, and he or she had withdrawn from one science class. Each faculty member was asked to rate John or Jennifer on a scale of one to seven in terms of competence, hireability, likability and the extent to which the professor might be willing to mentor the student. The professors were then asked to choose a salary range they would be willing to pay the candidate.

The results were startling. No matter the respondent’s age, sex, area of specialization or level of seniority, John was rated an average of half a point higher than Jennifer in all areas except likability, where Jennifer scored nearly half a point higher. Moreover, John was offered an average starting salary of $30,238, versus $26,508 for Jennifer. Handelsman told me that whenever she and Moss-Racusin show the graph to an audience of psychologists, “we hear a collective gasp, the significance is really so big.”

I asked Handelsman if she was surprised that senior female faculty members demonstrated as much bias as male professors, regardless of age, and she said no she had seen too many similar results in other studies. Nor was she surprised that the bias against women was as strong in biology as in physics or chemistry, despite the presence of more female biologists in most departments. Biologists may see women in their labs, she says, but their biases have been formed by images and attitudes they have been absorbing since birth. In a way, Handelsman is grateful that the women she studied turned out to be as biased as the men. When she gives a talk and reveals the results, she said, “you can watch the tension in the room drop. I can say: ‘We all do this. It’s not only you. It’s not just the bad boys who do this.’ ”

I asked Handelsman about the objection I commonly heard that John is a stronger name than Jennifer. She shook her head. “It’s not just a question of syllables, believe me,” she said. “There have been studies of which names convey the same qualities to respondents in surveys, and John and Jennifer are widely seen as conveying the same level of respectability and competence.” That faculty members reported liking Jennifer more than John makes the covert bias all the more insidious. As the authors make clear, their results mesh with the findings of similar studies indicating that people’s biases stem from “repeated exposure to pervasive cultural stereotypes that portray women as less competent by simultaneously emphasizing their warmth and likability compared to men.”

And when you combine that subconscious institutional bias with the internal bias against their own abilities that many young female scientists report experiencing, the results are particularly troubling. Of all the data her study uncovered, Handelsman finds the mentoring results to be the most devastating. “If you add up all the little interactions a student goes through with a professor — asking questions after class, an adviser recommending which courses to take or suggesting what a student might do for the coming summer, whether he or she should apply for a research program, whether to go on to graduate school, all those mini-interactions that students use to gauge what we think of them so they’ll know whether to go on or not. . . . You might think they would know for themselves, but they don’t.” Handelsman shook her head. “Mentoring, advising, discussing — all the little kicks that women get, as opposed to all the responses that men get that make them feel more a part of the party.”

Some critics argue that no real harm is done if women choose not to go into science. David Lubinski and Camilla Persson Benbow, psychologists at Vanderbilt University, spent decades studying thousands of mathematically precocious 12-year-olds. Their conclusion? The girls tended from the start to be “better rounded” and more eager to work with people, plants and animals than with things. Although more of the boys went on to enter careers in math or science, the women secured similar proportions of advanced degrees and high-level careers in fields like law, medicine and the social sciences. By their mid-30s, the men and women appeared to be equally happy with their life choices and viewed themselves as equally successful.


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