Via Seed, a group of economists chose to study human relationship dynamics under tightly controlled conditions: speed dating. Emphasis added.

With the obvious qualification that we’re talking here about a four-minute version of love and dating, we found that men did put significantly more weight on their assessment of a partner’s beauty, when choosing, than women did. We also found that women got more dates when they won high marks for looks from research assistants, who were hired for the much sought-after position of hanging out in a bar to rate the dater’s level of attractiveness on a scale of one to 10.

By contrast, intelligence ratings were more than twice as important in predicting women’s choices as men’s. It isn’t exactly that smarts were a complete turnoff for men: They preferred women whom they rated as smarter—but only up to a point. In a survey we did before the speed dating began, participants rated their own intelligence levels, and it turns out that men avoided women whom they perceived to be smarter than themselves. The same held true for measures of career ambition—a woman could be ambitious, just not more ambitious than the man considering her for a date.

When women were the ones choosing, the more intelligence and ambition the men had, the better. So, yes, the stereotypes appear to be true: We males are a gender of fragile egos in search of a pretty face and are threatened by brains or success that exceeds our own. Women, on the other hand, care more about how men think and perform, and they don’t mind being outdone on those scores.

Men can be such wimps sometimes.

The Higgs boson..the “God Particle” (ick…sorry Leon). The Holy Grail of particle physics. (Um, also there’s that dark matter stuff but who knows what it might be…)

Where to begin? The Higgs boson is one thing, or many, there, or not, waiting to be discovered, if we can. But what is it? Why is it? Does it exist at all?

We know a lot, now, after decades of experiments at the great accelerators. Working backwards: the Tevatron at Fermilab, LEP 1 and 2 at CERN, KEK-B at KEK in Japan, PEP2 at SLAC, CESR at Cornell, the SLC at SLAC, the SppS at CERN, HERA at DESY, Tristan at KEK, PEP at SLAC, PETRA at DESY. But it’s all coming down, sooner or later, to the Big One: the LHC at CERN. This machine will, in all likelihood, answer the question: what is the origin of electroweak symmetry breaking? That is, why do the carriers of the weak nuclear force, the W and Z bosons, have mass (and large mass at that) and the photon does not have mass at all? If we are really lucky we may start to get an answer to the question: why do fundamental particles have masses at all, and the rather peculiar masses they do have? And even if we know all this, so what? What then?

That was a lot of jargon and acronyms for one paragraph…so we’ll start there. Firstly, the word “electroweak”. We believe that all of the particles we know about interact “electroweakly” in the sense that they all partake of the weak nuclear force and, if they have electric charge, interact electromagnetically as well. We believe that the electromagnetic and weak nuclear forces are manifestations of a single underlying force of nature. The word “electromagnetic” should start to give you the flavor of the enterprise. Electricity=magnetism has been with us for nearly 150 years, first unified in the form of the “classical” electromagnetic relations of James Clerk Maxwell in 1861. This feat gave humanity its first taste of victory over matter, energy, space, and time, and propelled us headlong into the modern age. Surely one could unify electromagnetism with the other obvious force of nature, gravity, the universal nature of which was established in the late 1600’s by Isaac Newton.

But no. Gravity has stubbornly resisted unification to this day. Perhaps more on that later. Meanwhile, the late 1800’s and early 1900’s saw an incredible unfolding of unexpected events: the establishment of an apparently absolutely empty vacuum (no “ether” to serve as host to electromangetic waves), the undeniable ultimate universal speed limit namely that of light. Then in rather quick succession came the quantum, special relativity, the atom, the nucleus, and finally the dawning of the quantum mechanical description of our world.

By 1930 the quantum revolution was complete, and we could set about the usual human pattern of (intellectual) colonization, militarization, exploitation, and capitalization. All the modern technology we now enjoy derives principally on our ability to first understand and then technologize the quantum world.

Continue reading ‘Higgs 101′

I’m back from the Beyond Belief II conference at the Salk Institute in La Jolla, which packed an extraordinary amount of intellectual stimulation into a few short days. Any conference where you wander into the opening reception, get drawn into a conversation about reductionism and meaning with Stuart Kauffman, Rebecca Goldstein, and Sir Harold Kroto, and end up closing down the bar, is bound to be a good one, and this did not disappoint. (The title notwithstanding, much of the conference had little to do with atheism or religion — the subtitle “Enlightenment 2.0″ gave a better flavor.) The talks provided fodder for at least ten to twenty blog posts, of which I’ll probably get around to writing one or two.

One of the talks was by local neuroscientist V.S. Ramachandran, or “Rama” to his friends. (Like any good neuro person, his web page includes a fun collection of optical illusions.) He talked about his experiments with synesthesia, the phenomenon in which people see graphemes (e.g. numbers or letters) as associated with colors. I do that a little bit — five is certainly yellow, seven is red, and eight is blue — but it’s closer to a vague association than a vivid experience. Some people report very strong synesthetic reactions, and for a long time researchers have wondered whether the experience was mostly metaphorical or something stronger.

To test synesthesia, Rama and collaborators designed an experiment where they could measure the vividness of the colors associated with the numbers 2 and 5. They chose those because you can make them look almost identical, although reversed, by choosing a boxy font. Then they made up a picture (on left) of mostly fives, with a few twos scattered within there. Then they asked people to pick out the twos. Most ordinary folks could do it within about twenty seconds or so.

But true synesthetes could do it immediately. That’s because to them, the twos popped out as a brightly colored triangle (right). This established beyond much doubt that synesthesia was “real,” and more particularly that was a measurable phenomenon with real consequences.

This, in turn, strengthened the hypothesis that the origin of synesthesia was to be found in the structure of the brain. Indeed, it turns out that the region of the brain responsible for processing graphemes lies adjacent to the region responsible for processing colors.

Continue reading ‘Martian Colors’

I love telling the stories of Neptune and Vulcan. Not the Roman gods, the planets that were originally hypothesized to explain the mysterious motions of other planets. Neptune was propsed by Urbain Le Verrier in order to account for deviations from the predicted orbit of Uranus. After it was discovered, he tried to repeat the trick, suggesting a new inner planet, Vulcan, to account for the deviations of the orbit of Mercury. It didn’t work the second time; Einstein’s general relativity, not a new celestial body, was the ultimate explanation.

In other words, Neptune was dark matter, and it was eventually discovered. But for Mercury, the correct explanation was modified gravity.

We’re faced with the same choices today, with galaxies and clusters playing the role of the Solar System. Except that the question has basically been answered, by observations such as the Bullet Cluster. If you modify gravity, it’s fairly straightforward (although harder than you might guess, if you’re careful about it) to change the strength of gravity as a function of distance. So you can mock up “dark matter” by imagining that gravity at very large distances is just a bit stronger than Newton (or Einstein) would have predicted — as long as the hypothetical dark matter is in the same place as the ordinary matter is.

But it’s enormously more difficult to invent a theory of modified gravity in which the direction of the gravitational force points toward some place other than where the ordinary matter is. So the way to rule out the modified-gravity hypothesis is to find a system in which the dark matter and ordinary matter are located in separate places. If you see a gravitational force pointing at something other than the ordinary matter, dark matter remains the only reasonable explanation.

And that’s precisely what the Bullet Cluster gives you. Dark matter that has been dynamically separated from the ordinary matter, and indeed you measure the gravitational force (using weak lensing) and find that it points toward the dark matter, not toward the ordinary matter. So, we had an interesting question — dark matter or modified gravity? — and now we know the answer: dark matter. You might also have modified gravity, but one’s interest begins to wane, and we move on to trying to figure out what the dark matter actually is.

But some people don’t want to give up. A recent paper by Brownstein and Moffat claims to fit the Bullet Cluster using modified gravity rather than dark matter. If that were right, and the theory were in some sense reasonable, it would be an interesting and newsworthy result. So, you might think, the job of any self-respecting cosmologist should be to work carefully through this paper (it’s full of equations) and figure out what’s going on. Right?

I’m not going to bother. The dark matter hypothesis provides a simple and elegant fit to the Bullet Cluster, and for that matter fits a huge variety of other data. That doesn’t mean that it’s been proven within metaphysical certainty; but it does mean that there is a tremendous presumption that it is on the right track. The Bullet Cluster (and for that matter the microwave background) behave just as they should if there is dark matter, and not at all as you would expect if gravity were modified. Any theory of modified gravity must have the feature that essentially all of its predictions are exactly what dark matter would predict. So if you want to convince anyone to read your long and complicated paper arguing in favor of modified gravity, you have a barrier to overcome. These folks aren’t crackpots, but they still face the challenge laid out in the alternative science respectability checklist: “Understand, and make a good-faith effort to confront, the fundamental objections to your claims within established science.” Tell me right up front exactly how your theory explains how a force can point somewhere other than in the direction of its source, and why your theory miraculously reproduces all of the predictions of the dark matter idea (which is, at heart, extraordinarily simple: there is some collisionless non-relativistic particle with a certain density).

And people just don’t do that. They want to believe in modified gravity, and are willing to jump through all sorts of hoops and bend into uncomfortable contortions to make it work. You might say that more mainstream people want to believe in dark matter, and are therefore just as prejudiced. But you’d be laboring under the handicap of being incorrect. Any of us would love to discover a modification of Einstein’s equations, and we talk about it all the time. As a personal preference, I think it would be immeasurably more interesting if cosmological dynamics could be explained by modifying gravity rather than inventing some dumb old particle.

But the data say otherwise. So most of us suck it up and get on with our lives. Don’t get me wrong: I’m happy that some people are continuing to work on a long-shot possibility such as replacing dark matter with modified gravity. But it’s really a long shot at this point. There is a tremendous presumption against it, and you would have to have a correspondingly tremendous theory to get people interested in the possibility. I don’t think it’s worth writing news stories about, in particular: it gives people who don’t have the background to know any better the idea that more or less everything is still up for grabs. But we do learn things and make progress, and at this point it’s completely respectable to say that we’ve learned that dark matter exists. Not what all of us were rooting for, but the universe is notoriously uninterested in adapting its behavior to conform to our wishes.

Juggling work and family, there are lots of corners one cuts. Beds go unmade, underwear is bought in bulk so that laundry never has to be done, and 8+ hours of sleep a night is the impossible dream. But, the one thing I cannot ever, ever scrimp on is Halloween. I could skip Christmas without shedding a tear, but Halloween must be celebrated full-on. It’s the one holiday that comes without obligations. No family rifts have ever sprung up over Halloween-related issues. No one has ever shed a tear because you forgot to get them a Halloween card. No, your only obligation is to have as much frivolous, pointless fun as possible, kind of like Spring Break without the puking and STDs.

For me, one of the pleasures of Halloween is getting to geek out on costumes. I have pretty much always obsessed about costumes, and tend to sink a huge amount of time into constructing them.

This kind of craftiness tends to be considered women’s domain, and I have absolutely no idea why. People who do not do crafts have no idea how interesting and technical these projects can be. When one of your kids announces they want to be a dolphin, and you need to figure out how to take a few square feet of fabric and notions and make something that looks like a dolphin (a dolphin, mind you, not a shark, though they are both greyish sea creatures with pointy snouts), you practically need a degree in astrophysics to figure out how to do it. And you know what? There are probably millions of women out there effortlessly carrying out what is in essence a complicated engineering task, and they, unlike me, don’t actually have degrees in astrophysics. It kills me that a large fraction of them have no idea that they’re demonstrating all the spatial reasoning and innovation and using-of-complicated machines that scientists and engineers use every day. Likewise, I don’t know why most guys tend to miss out on this. A well-crafted dolphin costume is immensely satisfying.