Expect problems and eat them for breakfast


A growing body of literature has shown that environmental exposures in the period around conception can affect the sex ratio at birth through selective attrition that favors the survival of female conceptuses. Glucose availability is considered a key indicator of the fetal environment, and its absence as a result of meal skipping may inhibit male survival.

We hypothesize that breakfast skipping during pregnancy may lead to a reduction in the fraction of male births. Using time use data from the United States we show that women with commute times of 90 minutes or longer are 20 percentage points more likely to skip breakfast. Using U.S. census data we show that women with commute times of 90 minutes or longer are 1.2 percentage points less likely to have a male child under the age of 2. Under some assumptions, this implies that routinely skipping breakfast around the time of conception leads to a 6 percentage point reduction in the probability of a male child. Skipping breakfast during pregnancy may therefore constitute a poor environment for fetal health more generally.

{ Biodemography and Social Biology | Continue reading }

photo { Ralph Eugene Meatyard, Occasion for Diriment, 1962 }

related { Determinants of online sperm donor success: How women choose }

Sometimes a scream is better than a thesis


Can people differentiate what they know from what they do not? Several lines of research suggest that people are not always accurate judges of their knowledge and often overestimate how much they know. Research on overconfidence finds that people commonly judge the accuracy of their judgments too favorably and typically overestimate how well they perform everyday tasks relative to other people. Work on the illusion of explanatory depth demonstrates that participants tend to think they have a better understanding of how objects work (e.g., a ballpoint pen) than they can demonstrate when that understanding is put to the test.

At times, people even claim knowledge they cannot possibly have, because the object of their knowledge does not exist, a phenomenon known as overclaiming. For example, in the late 1970s, nearly a third of American respondents expressed an opinion about the “1975 Public Affairs Act” when asked about it directly, even though the act was a complete fiction. Approximately a fifth of consumers report having used products that are actually nonexistent. More recent research has asked participants to rate their familiarity with a mix of real and nonexistent concepts, names, and events in domains such as philosophy, life sciences, physical sciences, and literature. Participants reported being familiar with the real items but also, to a lesser degree, with the nonexistent ones. […]

What underlies assertions of such impossible knowledge? We found that people overclaim to the extent that they perceive their personal expertise favorably. […]

A sizable body of work on how people evaluate their own knowledge suggests that they rely not only on a direct examination of their mental contents but also on a feeling of knowing. Notably, a feeling of knowing is often only weakly predictive of actual knowledge and appears to be informed, at least in part, by top-down inferences about what should be or probably is known. We theorized that such inferences are drawn from people’s preconceived notions about their expertise, inducing a feeling of knowing that then prompts overclaiming.

{ Psychological Science | PDF }

We are for the dark


Decades of research have shown that humans are so-called cognitive misers. When we approach a problem, our natural default is to tap the least tiring cognitive process. Typically this is what psychologists call type 1 thinking, famously described by Nobel Prize–winning psychologist Daniel Kahneman as automatic, intuitive processes that are not very strenuous.

This is in contrast to type 2 thinking, which is slower and involves processing more cues in the environment. Defaulting to type 1 makes evolutionary sense: if we can solve a problem more simply, we can bank extra mental capacity for completing other tasks. A problem arises, however, when the simple cues available are either insufficient or vastly inferior to the more complex cues at hand.

Exactly this kind of conflict can occur when someone chooses to believe a personal opinion over scientific evidence or statistics.

{ Scientific American | Continue reading }

‘Love is joy with the accompanying idea of an external cause.’ –Spinoza


Past research showed that people accumulate more knowledge about other people and objects they like compared to those they dislike. More knowledge is commonly assumed to lead to more differentiated mental representations; therefore, people should perceive others they like as less similar to one another than others they dislike.

We predict the opposite outcome based on the density hypothesis; accordingly, positive impressions are less diverse than negative impressions as there are only a few ways to be liked but many ways to be disliked. Therefore, people should perceive liked others as more similar to one another than disliked others even though they have more knowledge about liked others.

Seven experiments confirm this counterintuitive prediction and show a strong association between liking and perceived similarity in person perception.

{ Journal of Experimental Social Psychology | Continue reading }

‘We have art lest we perish from the truth.’ –Nietzsche


What happens to us as we accrue knowledge and experience, as we become experts in a field? Competence follows. Effortlessness follows. But certain downsides can follow too. We reported recently on how experts are vulnerable to an overclaiming error – falsely feeling familiar with things that seem true of a domain but aren’t. Now a new paper in the Journal of Experimental Social Psychology explores how feelings of expertise can lead us to be more dogmatic towards new ideas.

{ BPS | Continue reading }

Be careful not to gamble on a guy with a suitcase and a ticket getting out of here


In Experiment 1 (N = 218), where female participants rated male facial attractiveness, the facilitative effect of smiling was present when judging long-term partners but absent for short-term partners. This pattern was observed for East Asians as well as for Europeans. […]

Related to this issue, Morrison et al. (2013) compared the attractiveness of faces displaying the six basic emotions (anger, disgust, fear, happiness, sadness, and surprise). Faces with a happy expression were rated to be more attractive than faces with the other emotions, but they were rated as attractive as neutral ones.

{ Evolutionary Psychology | Continue reading }

related { Transferring the expressions of one person’s face to the other in realtime }

And then he’s drunk and never even told her that he cared


This research examines the role of alcohol consumption on self-perceived attractiveness. Study 1, carried out in a barroom (N= 19), showed that the more alcoholic drinks customers consumed, the more attractive they thought they were.

In Study 2, 94 non-student participants in a bogus taste-test study were given either an alcoholic beverage (target BAL [blood alcohol level]= 0.10 g/100 ml) or a non-alcoholic beverage, with half of each group believing they had consumed alcohol and half believing they had not (balanced placebo design). After consuming beverages, they delivered a speech and rated how attractive, bright, original, and funny they thought they were. The speeches were videotaped and rated by 22 independent judges. Results showed that participants who thought they had consumed alcohol gave themselves more positive self-evaluations. However, ratings from independent judges showed that this boost in self-evaluation was unrelated to actual performance.

{ British Journal of Psychology | PDF }

‘The flame is not so bright to itself as to those on whom it shines: so too the wise man.’ —Nietzsche


Starting at age 55, our hippocampus, a brain region critical to memory, shrinks 1 to 2 percent every year, to say nothing of the fact that one in nine people age 65 and older has Alzheimer’s disease. The number afflicted is expected to grow rapidly as the baby boom generation ages. Given these grim statistics, it’s no wonder that Americans are a captive market for anything, from supposed smart drugs and supplements to brain training, that promises to boost normal mental functioning or to stem its all-too-common decline. […]

A few years back, a joint study by BBC and Cambridge University neuroscientists put brain training to the test. Their question was this: Do brain gymnastics actually make you smarter, or do they just make you better at doing a specific task? […] All subjects took a benchmark cognitive test, a kind of modified I.Q. test, at the beginning and at the end of the study. Although improvements were observed in every cognitive task that was practiced, there was no evidence that brain training made people smarter.

There was, however a glimmer of hope for subjects age 60 and above. Unlike the younger participants, older subjects showed a significant improvement in verbal reasoning, one of the components of the benchmark test, after just six weeks of brain training, so the older subjects continued in a follow-up study for a full 12 months.

Results of this follow-up study, soon to be published in a peer-reviewed journal, generally show that continued brain training helps older subjects maintain the improvement in verbal reasoning seen in the earlier study. This is good news because it suggests that brain exercise might delay some of the effects of aging on the brain.

{ NY Times | Continue reading }

They say any artist paying six dollars may exhibit


Experts say fakes have become one of the most vexing problems in the art market. […]

Two years ago, the center, known for its work in bioengineering, encryption and nanotechnology, set about developing a way to infuse paintings, sculptures and other artworks with complex molecules of DNA created in the lab. […]

The new approach, in its formative stage, would implant synthetic DNA, not the personal DNA of the artists, because of privacy issues and because a person’s DNA could conceivably be stolen and embedded, thus undermining the authority of such a marking protocol.

The developers said the bioengineered DNA would be unique to each item and provide an encrypted link between the art and a database that would hold the consensus of authoritative information about the work. The DNA details could be read by a scanner available to anyone in the art industry wanting to verify an object.

{ NY Times | Continue reading }

installation { Yayoi Kusama, The obliteration room, 2002-present }

Why pamper life’s complexities when the leather runs smooth on the passenger seat?


Statisticians love to develop multiple ways of testing the same thing. If I want to decide whether two groups of people have significantly different IQs, I can run a t-test or a rank sum test or a bootstrap or a regression. You can argue about which of these is most appropriate, but I basically think that if the effect is really statistically significant and large enough to matter, it should emerge regardless of which test you use, as long as the test is reasonable and your sample isn’t tiny. An effect that appears when you use a parametric test but not a nonparametric test is probably not worth writing home about.

A similar lesson applies, I think, to first dates. When you’re attracted to someone, you overanalyze everything you say, spend extra time trying to look attractive, etc. But if your mutual attraction is really statistically significant and large enough to matter, it should emerge regardless of the exact circumstances of a single evening. If the shirt you wear can fundamentally alter whether someone is attracted to you, you probably shouldn’t be life partners. […]

In statistical terms, a glance at across a bar doesn’t give you a lot of data and increases the probability you’ll make an incorrect decision. As a statistician, I prefer not to work with small datasets, and similarly, I’ve never liked romantic environments that give me very little data about a person. (Don’t get me started on Tinder. The only thing I can think when I see some stranger staring at me out of a phone is, “My errorbars are huge!” which makes it very hard to assess attraction.) […]

I think there’s even an argument for being deliberately unattractive to your date, on the grounds that if they still like you, they must really like you.

{ Obsession with Regression | Continue reading }

Call me morbid, call me pale, I’ve spent six years on your trail


Neurotechnologies are “dual-use” tools, which means that in addition to being employed in medical problem-solving, they could also be applied (or misapplied) for military purposes.

The same brain-scanning machines meant to diagnose Alzheimer’s disease or autism could potentially read someone’s private thoughts. Computer systems attached to brain tissue that allow paralyzed patients to control robotic appendages with thought alone could also be used by a state to direct bionic soldiers or pilot aircraft. And devices designed to aid a deteriorating mind could alternatively be used to implant new memories, or to extinguish existing ones, in allies and enemies alike. […]

In 2005, a team of scientists announced that it had successfully read a human’s mind using functional magnetic resonance imaging (fMRI), a technique that measures blood flow triggered by brain activity. A research subject, lying still in a full-body scanner, observed a small screen that projected simple visual stimuli—a random sequence of lines oriented in different directions, some vertical, some horizontal, and some diagonal. Each line’s orientation provoked a slightly different flurry of brain functions. Ultimately, just by looking at that activity, the researchers could determine what kind of line the subject was viewing.

It took only six years for this brain-decoding technology to be spectacularly extended—with a touch of Silicon Valley flavor—in a series of experiments at the University of California, Berkeley. In a 2011 study, subjects were asked to watch Hollywood movie trailers inside an fMRI tube; researchers used data drawn from fluxing brain responses to build decoding algorithms unique to each subject. Then, they recorded neural activity as the subjects watched various new film scenes—for instance, a clip in which Steve Martin walks across a room. With each subject’s algorithm, the researchers were later able to reconstruct this very scene based on brain activity alone. The eerie results are not photo-
realistic, but impressionistic: a blurry Steve Martin floats across a surreal, shifting background.

Based on these outcomes, Thomas Naselaris, a neuroscientist at the Medical University of South Carolina and a coauthor of the 2011 study, says, “The potential to do something like mind reading is going to be available sooner rather than later.” More to the point, “It’s going to be possible within our lifetimes.”

{ Foreign Policy | Continue reading }

‘The journey of a thousand miles begins with a single step.’ —Lao Tzu


Imagine that you are imprisoned in a tunnel that opens out onto a precipice two paces to your left, and a pit of vipers two paces to your right. To torment you, your evil captor forces you to take a series of steps to the left and right. You need to devise a series that will allow you to avoid the hazards — if you take a step to the right, for example, you’ll want your second step to be to the left, to avoid falling off the cliff. You might try alternating right and left steps, but here’s the catch: You have to list your planned steps ahead of time, and your captor might have you take every second step on your list (starting at the second step), or every third step (starting at the third), or some other skip-counting sequence. Is there a list of steps that will keep you alive, no matter what sequence your captor chooses?

In this brainteaser, devised by the mathematics popularizer James Grime, you can plan a list of 11 steps that protects you from death. But if you try to add a 12th step, you are doomed: Your captor will inevitably be able to find some skip-counting sequence that will plunge you over the cliff or into the viper pit.

Around 1932, Erdős asked, in essence, what if the precipice and pit of vipers are three paces away instead of two? What if they are N paces away? Can you escape death for an infinite number of steps? The answer, Erdős conjectured, was no — no matter how far away the precipice and viper pit are, you can’t elude them forever.

But for more than 80 years, mathematicians made no progress on proving Erdős’ discrepancy conjecture (so named because the distance from the center of the tunnel is known as the discrepancy).

{ Quanta | Continue reading }