Jose Drost-Lopez

Archive for 2011|Yearly archive page

Research on meditation, mindfulness and related psychotherapies

In Cognitive Sciences, Religions and spirituality on November 13, 2011 at 1:59 am

Buddhism involves not just a set beliefs but also a set of practices. Two of the most important and interrelated Buddhist practices are mindfulness and meditation. Both of these concepts have many formulations in different schools of Buddhist thought, but I’d like to zero in on a simplified definition of mindfulness that has guided Western psychologists and psychiatrists. In this definition, mindfulness has two components:

(1) Purposely keeping one’s attention on the flow of experiences in the present moment

(2) An attitude of nonjudgmental curiosity, openness, and acceptance toward these present experiences.

Having defined mindfulness, we can also take an initial stab at what counts as meditation. Meditation is a procedure for mindfully exploring and transforming one’s mind. Examples of traditional meditation styles include Transcendental Meditation, which involves concentrating on a mantra, and compassion meditation, which involves projecting one’s love and kindness to all sentient beings. Though attempts to adapt meditation have a long, global history, one recent trend in the West is to strip meditation down to a secular, easy to learn process intended to promote mental and bodily health.

Having defined mindfulness and mediation, we’re almost ready to talk about the research relating to them—but first a little history. Buddhism is like most disciplines that study the mind in that it existed long before experimental psychology. But when psychology did emerge in the late 19th and early 20th centuries, one particular psychologist stood out in welcoming influences from Buddhism. His name was William James, and he’s remembered as one of the greatest American psychologists. In his 1890 work The Principles of Psychology, he popularized a concept borrowed from Buddhist texts known as stream of consciousness. James borrowed that phrase to point out that our perceptions flow together seamlessly even though they integrate many distinct elements and discrete moments. In his later writings James promoted meditation as a useful introspective and therapeutic tool. Referring to Buddhism, he proclaimed: “This is the psychology everybody will be studying twenty-five years from now.” It turns out he was basically wrong—the next big influences in psychology were the psychoanalysis of Sigmund Freud, an Austrian, and the behaviorism of B.F. Skinner, an American. Even still, plenty of psychologists and writers over the decades tried to integrate Buddhist ideas into their thought. Then in the 1970s, psychologists and neuroscientists started collecting data from Buddhist practitioners.

One of the largest lines of research on meditation has involved a technique called electroencephalography, or EEG. In EEG, electrodes are placed along the scalp to detect voltage fluctuations due to the electrical activity of the brain. EEG has some limitations—for example, it only picks up on large bursts of activity, and it gives only a very rough sense of where in the brain neurons are firing. But the biggest limitations in these studies have related to their design: often they badly controlled, unclear in their definitions and sloppy in their data collection.

So these EEG studies are a work in progress and they’re difficult to interpret, but they do generally support two points. First, meditation and mindfulness exercises cause unique patterns of brain activity. These patterns seem to represent states of awareness that at are least partially separate from related states of relaxation, drowsiness, or concentration. The second main point is that practitioners’ brain activity depends on their experience level, intensity, and style of training, which suggests that meditation and mindfulness involve somewhat different experiences in different people.

The experience of meditation, like that of many spiritual practices, involves a diminished sense of self, space and time. These subjective feelings have been validated in various brain EEG studies. The studies show decreased activity in a part of parietal lobe that monitors location in space, as well as increased activity in parts of the frontal lobe involved in attention.

Beyond EEG there have been more recent studies that look meditating brains in a different way. One study that really made a media splash back in 2005 showed an association between meditation experience and thickness in the outer layer of the brain, or the cerebral cortex. Although there is a possibility that the 20 practitioners of insight mediation in this study had thicker cortices for reasons unrelated to meditation, the most plausible interpretation of the association is that in some parts of the cortex, meditation can slow down the thinning that occurs as people age. This might mean mediation can slow down cognitive decline at certain stages.

But meditation cheerleading can be taken too far, as psychologist Mark Epstein learned  in a meditation session gone bad. The setting was a spiritual retreat led by an American teacher named Ram Dass. One of the students at this retreat, a young man, started showing signs of hallucinations and psychotic delusions. Epstein observed as this happened, and was intrigued at the opportunity to see a spiritual approach to dealing with a psychotic person. Ram Dass spent a few minutes chanting with the young man and trying to center him meditatively, but the man became agitated and violent. As the man began to lash out, Ram Dass restrained him, but in the process the man bit Ram Dass in the stomach. Soon afterward he was prescribed anti-psychotic drugs. Commenting on this episode, Epstein points out that meditation is not an all-purpose panacea, and that Western approaches including medications can be assets in promoting well-being.

The power of meditation shows itself beyond the brain. Cardiologist Herbert Benson found that experienced practitioners can decrease their blood pressure, heart rate, and oxygen consumption. Benson calls this physiological response the relaxation response. Benson helps his patients initiate this response by introducing his patients to a simple meditative relaxation exercise. This exercise is simple for you to try. It involves sitting in a comfortable position, breathing deeply, relaxing all the muscles from toe to face, closing your eyes, and focusing on a single word or phrase. Benson’s patients usually focus on a favorite prayer, which brings up an interesting point about the portability of meditation practices across religious divides. That prayer can just as easily be Christian or Muslim and make for an effective session. Picking up this thread, the psychology textbook writer David Myers points out that meditative techniques have a long history in many religious traditions, and he gives the example of Gregory of Sinai, who in the early 1300s wrote basic instructions for Christians to meditate on Jesus.

There will plenty more progress in understanding meditation in the brain, but beware of vague headlines. Here are two recent headlines from major news outlets: “Brain scans show meditation changes minds.” “Compassion meditation changes the brain.” These claims might have a ring of impressiveness at first, but they usually just echo the mundane fact that all our experiences change the brain.

Mindfulness and psychotherapy

There’s a tantalizing but sometimes inconclusive body of evidence related to mindfulness-inspired therapy programs. Two increasingly popular therapeutic practices using Buddhist mindfulness techniques are Jon Kabat-Zinn’s Mindfulness-based Stress Reduction (MBSR) and Marsha M. Linehan’s Dialectical Behavioral Therapy (DBT). Other prominent therapies that use mindfulness include Steven C. HayesAcceptance and Commitment Therapy (ACT) and, based on MBSR, Mindfulness-based Cognitive Therapy (MBCT).

Studies on these therapies show a surprising twist—there are documented adverse effects of mindfulness training, although they are almost always minor enough to be outweighed by the benefits. In part-time programs, these adverse effects include the mental discomfort and guilt that people feel when they fail to live up to some of their resolutions and expectations. In intensive retreats, some people mention vivid perceptual alterations during meditation, and a small study at one retreat even suggested that more experienced practitioners had spontaneous hallucinations and unusual perceptions more often, although they didn’t dwell much on these disturbances.

Now to the positive findings. Across the board, mindfulness-based interventions decrease people’s self-reported feelings of stress. Mindfulness exercises also lower people’s focus on financial gain, which in turn boosts their self-reported happiness. There a lot of more specific benefits attributed to mindfulness, but in assessing these claims, we have to be careful about turning a blind eye to classic problems that confront psychology experiments. Usually the experimenter can’t avoid biasing results due to their expectations and assumptions. That’s why in clinical trials the gold standard is the double-blind trial, in which neither the patient nor doctor know which treatment is being administered. Of course it’s not feasible to blind people to what type of counseling they give or receive, so we have the accept the presence of self-fulfilling expectations, especially in participants in counseling programs, who are likely to initiate a strong placebo response to that has little to do with mindfulness or meditation per se. In addition, studies of mindfulness programs often have small sample sizes, roughly meaning groups under 30 people, in which chance anomalies are easy to mistake for positive or negative results.

So let’s shift back to Mindfulness Based Stress Reduction, or MBSR. This is an eight-week part-time program developed by Jon Kabat-Zinn over a ten year period with over four thousand patients at the University of Massachusetts Medical Center. Kabat-Zinn deserves a lot of credit for initiating serious clinical studies of mindfulness techniques. But what do the studies say?

When psychologist Richard Davidson at the University of Wisconsin assigned volunteers either to a control group or two an eight-week MBSR course, the trained volunteers showed more left-hemisphere activity, which is associated with positive emotions, and improved immune functioning. These benefits may help explain a 1989 study of 73 residents of homes for the elderly that randomly assigned them to Transcendental Meditation, mindfulness training, relaxation training, or no intervention. After three years, it was clear that the meditation training group was healthiest, followed by the mindfulness group. Whereas no one in the meditation group had died, a fourth of the control group had died. Meditators also performed best on a battery of tests and ratings for associative learning; cognitive flexibility; word fluency; mental health; systolic blood pressure; behavioral flexibility and aging,

Then there was a 2004 meta-analysis in the Journal of Psychosomatic Research that reviewed 64 research reports and aggregated the results of the 20 studies that met quality criteria. They found that MBSR can help a broad range of individuals cope with clinical and nonclinical problems. Most studies showed similar statistical effect sizes of about 0.5, which means that the average MBSR participant had better mental health than 69% of people in the general population. Note that this modest effect size is comparable with the effectiveness of established Western psychotherapy techniques.

Dialectical Behavioral Therapy (DBT) is another Western-style approach to therapy that draws on Buddhism. It encourages neutral acceptance of unpleasant facts and includes mindfulness training as a core skill to enact change. DBT was designed help people with mood disorders and personality disorders, so studies of its effectiveness haved focus on these disorders. Controlled clinical studies have demonstrated DBT’s effectiveness for people with borderline personality disorder. Research indicates that DBT is also effective in treating patients who present varied symptoms and behaviors associated with spectrum mood disorders, including self-injury. Recent work suggests its effectiveness with sexual abuse survivors and chemical dependency.

Our whirlwind tour is coming to a close. You can learn much more from Chris Mace of the University of Warwick. Through the interplay of meditation and mindfulness with Western science and therapy, Buddhism has made a profound contribution to science with its mindfulness and meditation techniques and  many aspects of Buddhist beliefs complement the latest orthodoxy in neuropsychology. Science still has plenty to learn from and about Buddhism, and conversely, Buddhist teachings are still assimilating modern research findings. In the coming years it will be fun to watch that cross-pollination on a larger and larger scale.

 

This is the last in a series  on Buddhism and neuropsychology. Read more:

The origin story of Buddhism

Contrasting views of the self

Preventing depression and boosting well-being with mindfulness (videos)

The Self: Buddhism vs Neuropsychology

In Cognitive Sciences, Religions and spirituality on November 13, 2011 at 12:54 am

The Buddhist view of the self has fascinating overlaps with the orthodox view among today’s neuroscientists. To Buddhists, the sense of self is an harmful illusion in the mind,  a fiction foisted onto perception. The pros and cons of selfhood are subtle, but let’s start with the point of agreement: our sense of self is deceptive. The key deception is the notion unity and consistency in our personalities.

False unity

In his book How the Mind Works, Steven Pinker describes the mind as a collection of specialized modules and submodules with different functions. For the most part these modules crunch information outside our awareness much the way computers do, which allows us to perceive, navigate, and survive in the world. But then there are more general modules that weigh in directly on our decisions. Think for a moment about the disgraced Congressman Anthony Weiner, who sent lewd pictures of himself to women he didn’t know. We can imagine a conflict in his mind between modules craving sex and dominance and very separate modules that regulate his behavior according to social norms. We’d have to assume that his modules for forecasting future consequences were mostly inactive or simply overpowered by urges from elsewhere in the brain.

The picture that results from this line of thinking is one of many processes in the brain bickering with each other, struggling to overpower the others like vote-hungry politicians or rival states in a confederacy. This is sort of bickering that Freud hypothesized between the Ego, the Superego, and the Id, but it’s more fragmented than that.  All our choices are the final acts of arguments in the brain that can take place on the order of milliseconds or days. And our sense of self is something like a CEO telling a post-hoc story about his corporation. We are only aware of a tiny sliver of what is happening throughout our minds. And this isn’t just idle speculation—there’s a large body of research documenting that unconscious social, physical, and language cues affect people’s behaviors, and documenting that people easily make up false stories to explain their disparate thought processes (David Eagleman’s new book drives this home).

The main takeaway is that Buddhists have been right to doubt our feeling of consistent control over our minds. The way things feel isn’t the way things are. The mind does not take a static stance, but is instead in constant flux, and this resonates with the Buddhist concept of impermance, or anicca. At some point, however, neuroscience becomes a bit more counterintuitive than Buddhism. Whereas  most Buddhist writings assert some sort of free will that allows people to be morally accountable, hard determinism is the dominant assumption in science. Here is a long quote from Joshua Green and colleagues elaborating on this assumption:

Neuroscience holds the promise of turning the black box of the mind into a transparent bottleneck. There are many causes that impinge on behaviour, but all of them—from the genes you inherited, to the pain in your lower back, to the advice your grandmother gave you when you were six—must exert their influence through the brain. Thus, your brain serves as a bottleneck for all the forces spread throughout the universe of your past that affect who you are and what you do. every decision is a thoroughly mechanical process, the outcome of which is completely determined by the results of prior mechanical processes. we have little reason to doubt that (i) the state of the universe 10 000 years ago, (ii) the laws of physics, and (iii) the outcomes of random quantum mechanical events are together sufficient to determine everything that happens nowadays, including our own actions. These things are all clearly beyond our control.”

Effects of selfhood

Buddhism and science are not nearly as aligned in their views on how harmful the self is. There’s no doubt that, as taught in Buddhism, anxieties and insecurities are tied up with self-conscious, judgmental thinking. And there’s also little doubt that decreasing self-conscious thought will generally boost people’s well-being. One famous psychologist, Mikhail Csíkszentmihályi, has found that happy people tend to seek interesting and challenging experiences that fully immerse their attention and channel their motivation. The resulting state is called flow, colloquially known as being “in the zone” or “on the ball,” and as in mindfulness, flow involves loosing the grip of self-consciousness and focusing attention on the moment. But beyond this initial agreement, psychology can help deconstruct the vague idea of the self into specific dimensions. These include an awareness of our body, an awareness of certain types of thoughts, a feeling of ownership and control over the mind, memories of events in our life, an interpretation of our social identity, a concept of our physical and mental traits, and a sense of consistent goals and values. It’s worth looking at some of these dimensions separately to check if some of them are useful, or maybe just plain unavoidable.

One crucial aspect of the self is called agency, which is the personal experience of creating our thoughts and actions. Never mind that agency can be a misleading feeling—there are many documented psychiatric and neurological disorders that remind us how agency can be desirable. Take schizophrenia, for example, which often involves an impaired sense of agency. Many schizophrenics experience their thoughts and actions as foreign. Here are some real examples from schizophrenic patients of the broken boundary between self and other:

  • Auditory hallucinations: A woman hears a voice she attributes to God saying things like “Shut up and get out of here.
  • Thought insertion: A man feels that another man named Chris is shutting down is mind to plant thoughts about killing people.
  • Thought withdrawal: A man feels a mysterious force blocking him from thinking what he wants to think about.
  • Passivity experiences: “They inserted a computer into my brain. It makes me move to the left or right”
  • Made emotions: “It puts feelings into me…”
  • Somatic passivity: “I have tingling feelings in my legs caused by electrical currents from an alternator.”

All these experiences of impaired agency tend to be disturbing and provoke paranoia. For Jared Loughner, the schizophrenic who shot representative Gabrielle Gifford’s, this paranoia fuels his belief that the government exerts mind control on everyone by controlling grammar. So in schizophrenia, the loss of agency, which we might call an involuntary breakdown in the illusion of self-control, causes more suffering than it prevents.

Of course for most people there’s no reason to legitimately worry about losing basic aspects of agency and self-concept. My point is that our sense of self has multiple components and that only some of them are worth diminishing.

Dementia in elderly people also features certain impairments of self. In Alzheimer’s disease, harmful plaques first develop in the hippocampus and precuneus, two areas key to recalling our past and imagining our future. As a result Alzheimer’s patients gradually lose their internal life story. Then there’s frontotemporal dementia, which more dramatically challenges our intuitions about self. In frontotemporal dementia, large swaths the frontal and temporal lobes degenerate, often leading to surprising personality changes. Science writer Carl Zimmer gives some examples: “One patient… had collected jewelry and fine crystal for much of her life before abruptly starting to gather stuffed animals at age 62. A lifelong conservative, she began to berate people in stores who were buying conservative books. Other patients have suddenly converted to new religions or become obsessed with painting or photography when they previously had no interest.”

Based on these glimpses of self-related dysfunction, I hope you can develop a more refined sense of what’s worth holding onto or letting go of. Personally, I cannot avoid my sense of agency, but I’m glad for the coherency it gives to my daily life. And I’m definitely grateful to have a reliable store of autobiographical memories that help me tell a story about my past and future. Then there are aspects of myself I think should be more open to negotiation, such as my beliefs about my strengths and weaknesses. Untangling the self is a subtle challenge, and neuroscience suggests some of those self-bits are welcome to stay.

The Story of Buddhism

In Religions and spirituality, Stories on November 12, 2011 at 11:56 pm

This is the first of a series of posts on Buddhism and psychology, based on my PsychTalk interview on the same topic. Without further ado, let’s start off with a story:

Buddhism began with a prince born in a small kingdom in the Northeastern part of the Indian subcontinent. This prince was named Siddhārtha Gautama. In the traditional account, he grew up with little knowledge of religions or of the suffering in the world. His marriage was arranged at 16 and he had a son, named Rahul. At the age of 29 he finally ventured away from palace, and he was surprised to meet a very old man. His charioteer explained to him that everyone ages until death. Siddharta made more trips into town, leading him to face a diseased man, a corpse, and a begging holy man. Dissatisfied with his wealthy lifestyle and searching for meaning, he left his life as a prince to live the simple, stoic life of an ascetic. He studied under two hermits, and then joined five companions to practice extreme self-deprivation. After a period of eating only a leaf or a nut a day, he collapsed in a river while washing himself. He almost drowned. This spurred him to reconsider his path. He decided to continue meditating but to reject extremes of deprivation or indulgence. His companions disagreed, viewing him as undisciplined, so they left him. Siddharta, now 35 years old, sat alone under a fig tree, vowing not to leave until he found truth. On his 49th day in this meditative journey, he is said to have attained the highest state of enlightenment, known as Nirvana. Soon he embarked on a journey to share his teachings, which collectively came to be known as the Dharma. After his death at the age of 80, his followers passed down his teachings by oral tradition for four centuries until they were gradually written down in the first century before Christ. The first set of Buddhist scriptures was composed in northern India and is known as the Pali Canon. The Pali Canon underlies the oldest school of Buddhism known as Theravada. A separate array of texts developed in southern India became the focus of a second school known as Mahayana. Mahayana Buddhism had more mystical and devotional aspects but the same basic goals of enlightened awareness and of liberation from suffering. It became more popular than Theravada and spread East across the vast Asian continent, where it split into Tibetan Buddhism and East Asian forms. Skipping forward to today, Buddhism in all its forms is the fourth largest religion in the world after Christianity, Islam, and Hinduism. One of the most public Buddhist figures is the 14thDalai Lama, who leads the Yellow Hat sect of Tibetan Buddhism. The Dalai Lama takes a deep interest in science, especially neuroscience. And for that reason he’s a great segue for my main topic: the intersections of neuropsychology and Buddhism

Dilemma after death: when the truth is harmful

In Movies on September 24, 2011 at 1:34 am

Some philosophers have a great excuse to watch movies: stories help explore moral dilemmas. Here’s a dilemma from the trailer for the movie Margaret (my summary below):

A bus driver flirts with you for a few seconds while driving, causing him/her to hit and kill a pedestrian at the crosswalk. On a guilty and sympathetic impulse, you tell investigators that the traffic light was green, but it was actually red. You find out the bus driver takes care of a family and is a decent person. Do you correct your testimony, even though the driver will lose his/her job and be charged with a crime? Or do you let your lie stand and try to forget the whole thing?

 

Gladiator 5k pits young against old, men against women

In Math, Personal on June 2, 2011 at 5:42 am

Gladiator 5k Race Times (secs)


Two Saturdays ago, a Gladiator 5k took place in Cary, NC. It was a foot race with a few mandatory obstacles like high walls, nets, tunnels, and a mud pit. I had good fun as a participant. Though I scraped up my knees and I was unimpressed by the puddle of water designated as a “mud pit,” the thrill of leapfrogging 10-foot wooden walls outdid my complaints. Individual results were posted soon after the race in a big table. Though I’m not one to pore over tables, I did notice that one of the women who beat me was 42 (congrats!). I sent my mom an email to inspire her with that information. But surely I was giving her false hope? That question led me to unleash my stats software (JMP) in search of the associations between age, sex, and finishing time. I started with age:

Race Time By Age


The red line is a linear fit (least squares regression) with a slope of 3.16 seconds per year of age. Warning: since that line only explains 0.4% of the variation in race times (RSquare = .004), it really sucks at describing the data. The line would have sucked even more had I not removed three clear outliers—the slowest racers by far—who were in their 20s and 30s. So a linear model was mostly useless here; age and performance had essentially no association across competitors as a whole. If that doesn’t surprise you a bit, it should. After all, look at the ages of the competitors:

Age Distribution (n = 771)


As you can see, there was plenty of dispersion from the mean of 32.3 years (Standard Deviation = 8.4). We’re not just talking about a few fast 40-something and 50-something year-olds: Half of the 771 competitors were between 31 and 59 years of age. Somehow they fared about as well as the younger half in the 14 to 30 range, although the very fastest and very slowest racers were young. My guess is that the older group had a more athletic background than average, compensating for the mild slowing effect of aging. In fact I now suspect that in most amateur races the older competitors will have the same average speed as their younger counterparts due to self-selection effects.

Does a similar story about the compensating effect of self-selection apply to the women racers? No: the differences between the sexes were very noticeable. Here are the histograms of the female and male times, where the heights of the bars again reflect frequencies.

Female Times (N = 372, 1 outlier excluded)


Male Times (in sec, N = 395, 3 outliers excluded)


Above the bars, the median and mean are marked with a line and diamond; there was a 5 and 4 minute difference between them. I’d attribute most of that difference to physiology. The distribution for female times was roughly symmetrical whereas the male distribution was right-skewed. There are many ways to interpret this, but my tentative guess is that relatively slow men were more interested in the event than relatively slow women. This guess fits with the marketing style of the event, which emphasized toughness in a way that I think appealed more to guys. Just to nail home the idea that sex predicted performance more systematically than age, compare these two graphs (on the same scale):

Race Time By Sex

Race Time By Age Block

The red boxes enclose the middle 50% of the race times and the red middle line marks the median time. The boxes match much more closely on the right (between age groups) than on the left (between sexes). Of course, matching up box-and-whisker plots isn’t a precise business, so I sought a final verdict with the “difference value” (d), equal to the difference in group means divided by the standard deviation including both groups. For sex, d is 0.56, which Lise Eliot calls “medium”-sized. For age group, it is 0.03, which is tiny. To give some perspective, the d value for height difference between sexes is about 2.6. For scores on standardized science tests, or on evaluations of verbal fluency, d is about 0.35. Since I’m wading into mildly scandalous territory, I’ll throw in the usual caveat: differences within sexes are always much larger than differences between sexes. Only trivial exceptions come to mind (e.g., number of breasts or testicles). An additional, more specific caveat is that males and females at the race almost surely weren’t representative of the American or global population. If for some twisted reason all adults in the U.S. were forced to compete in a Gladiator 5k, I bet females could really give males run for their money in average time because a higher percentage of males are overweight.

The fun in graphing and analyzing data is that previously obscure patterns reveal themselves in fine detail. Even if this Gladiator data isn’t especially intriguing for those of you who weren’t there at the race, I hope I’ve reminded you of the power of statistics to organize information. Next time you find yourself fishing morsels out of a table, especially if that information has a personal connection to you, try graphing it!


Chasing perfection: a tale of sequential decision-making

In Math, Personal on May 29, 2011 at 2:54 am

Now *that's* my kind of piano teacher.

My grandest ‘real-life’ use of probability theory until recently was to estimate my odds in Risk and poker. Then, while skimming a math-themed book, I singled out a principle that will shape how I will spend $6,000 and about 200 hours of my life in the upcoming year. As far as the math goes, it doesn’t matter whether I’m referring to getting a girlfriend, a pet, an apartment, or a job. But at the moment I am actually picking a piano teacher. The teacher-picking theorem I have in mind is based on an oversimplified scenario that has an optimal strategy. Trying to apply it has been interesting. But before I reflect on my story, let’s glance at what the math says.

Sequential decisions

Start by imaging a series of candidates, among which we want to choose the very best. We have to assess candidates one at a time, and we have to decide whether to accept or reject them immediately after inspecting them. The candidates come to us in random order, so that the first one we assess is just as likely as the last one to be the best. The optimal strategy in this setup is to inspect about 37% (or exactly 1/e) of the candidates and then accept the next one that is better than the first 37%. This approach is optimal (i.e., mostly likely to snag the best option) because 37% of candidates is just enough to estimate which ones are exceptional without rejecting too exceptional ones.

“Sequential decision making,” as this scenario is sometimes called, first came to my attention in a psychology study. When healthy people do computerized sequential decision tasks—sometimes simulating job interviews or shopping—they tend to jump the gun. However, this study in Germany found that people suffering from depression tend to wait longer and more closely approximate the best strategy. While this line of research has interesting implications for the causes and origins of depression, my main personal reaction was a sense that I probably don’t sample enough options in my life decisions. A prime example heads off my piano story: I picked a piano teacher a two months ago by emailing a music professor I did not know and taking his recommendation. Out of 30 available teachers listed in a directory for my area, I ended up ‘sampling’ only 1/30 ( 3.3%) of them. That’s all the more suboptimal because with piano teachers I can choose earlier candidates, which justifies sampling a larger fraction of teachers than in “37% rule” I’ve described. My only defense is that the recommending professor seemed to be familiar with the candidates, so he probably ruled out some of the least compatible candidates.

The experiment

Fast forward to two weeks ago; I was now looking for a new piano teacher. Emboldened by my pet theorem, I emailed nine teachers (about 30% of my options) based on what little information I found online. It was not hard to pick four of the more interesting teachers to meet in person. I have now met three out of those four and I feel glad with my approach, but I am still making sense of the challenges involved. The main challenge is making fair comparisons. I started my search by de facto rejecting all the teachers I did not email based on little or no information; then I rejected some email respondents based on unreliable cues in their messages; and, in the final step, I made snap judgments from meetings that were subject to confounds like mood, time of day, shared expectations, and who knows what else. My two conclusions here are that (1) quality-assessments are imprecise, especially when they involve judging a match between people and (2) “counting” how many candidates have been “assessed” is subjective unless they all receive similar attention under similar conditions.

My next big hitch is about social emotions, not strategy. Specifically, my meetings so far were all at some point comically awkward, because in each case I did not want to admit how widely I had casted my net. I vaguely mentioned “considering my options” and, at most, I acknowledged meeting one other teacher. Although I don’t feel ashamed about my attempts to find a good match, I don’t want to upset teachers who might frown on my approach. After all, no one likes being compared to others or facing rejection. Thus I tried to treat each teacher as my top choice without making false promises. Looking to the future, I also wonder if more awkward situations will develop. Will any teachers gossip disapprovingly of me? Will I bump into “rejected” teachers at future recitals? These questions suggest that trying out multiple teachers has had a minor “emotional cost” for me. I imagine this type of cost could be much heavier in other choice processes like child adoption.

My final complaint with my piano teacher experiment is that it has been resource-intensive. The time and effort spent emailing, driving to and meeting people has felt subjectively like “too much.” The root of this complaint is that sequentially finding the best piano teacher in my area is not my only goal in life. I have other uses for my time, energy, and gasoline, like finding a part-time job, catching up with friends, and sleeping. Therefore I constantly have to weigh the value of finding a slightly better teacher against improving some other aspect of my life. At some point, my search is no longer worth it (economists, read: diminishing returns or increasing opportunity costs). The inevitable trade-offs we all face could partly explain, from both evolutionary and practical perspectives, why we tend not to sample quite enough alternatives to make the ‘optimal’ choice. Satoshi Kanawaza makes a related point about dating in densely populated cities like New York—at some point there are so many eligible bachelors around that meeting or speed-dating 37% of them is infeasible. We usually settle for “good enough,” and most times we have to.

Murky math and puppy paradoxes

These reflections should make clear that an idealized model of sequential decision making cannot replace mental assets such as good intuition, resourcefulness, and common sense. In spite of the apparent certainty of the “37% rule,” its most useful lesson for daily choices is vague: get a good sense of the candidate pool. In my search for piano teachers, the easiest way to scope out the field has been to contact a lot of teachers directly. But other ways to do that include asking experts or reviewers and drawing on relevant past experiences.

Unfortunately, knowing our options can be just as counterproductive as it is helpful for some highly subjective decisions. As Sheena Iyengar and Barry Schwartz are fond of pointing out, we humans are susceptible to “choice overload.” When we see too many retirement plans or job offers, we take irrational shortcuts and sometimes we feel less satisfied with whatever pick we make. For some of us (depending on culture, personality, and exact circumstances) the most adorable puppy possible is one of the first we see. If beauty is in the eye of the beholder, then the beholder is liable to get fatigued and jaded by alternatives.

It's easiest to have the puppy pick you.

It’s no surprise that marrying a mathematical theorem like the 37% rule with the complexity of human decision-making requires a laundry list of caveats. But even with the caveats, mathematicians and other logical sorts are on hand to help us if we ever get the urge to approximate “rational” thinking. The rest of the time, our unconscious brains can run a decent autopilot for us—and thank goodness for that.

(Disclaimer: I disavow myself of any responsibility, moral or legal, for terrible choices of piano teachers or puppies that result from your reading this post).

Die Hard in Spanish (The fun and mystery of translation discrepancies)

In Movies on May 17, 2011 at 12:51 pm

Or...Hasta la vista, bebe?

I recently popped Live Free or Die Hard from Netflix into my DVD player only to realize that I had already watched it. Undeterred by my memory mishap, I made the movie more interesting by adding Spanish dubbing and subtitles. I was in for a surprise. As amusing as it was to watch Bruce Willis destroy a helicopter with a kamikaze car and defeat seasoned martial artists with sloppy brawling, the oddities of the Spanish translations took me in.

In general, the dubbing and subtitles are drastically different in word choice and phrasing even though the meaning tends to feel similar enough. The subtitles look more like a transliteration, giving the impression that they were made directly from the English script with less eye to context. One telling example is the subtitled translation of “fire sale” coming out to “liquidación de incendio,” in contrast to “invasión general” in the dubbing. In context, “fire sale” is security jargon for the systematic takeover and shutdown of a country’s infrastructure, so the dubbing gets closer to the take-over-the-world gist.

Yet the extra layer of interpretation in the voice-over also felt less true to the film at times. A couple speechless or inaudible moments are “filled in” with dubbed Spanish, such as when an FBI character speaks inaudibly to generic staffers, and when Bruce Willis closes a car door on his hacker companion. I was also surprised by one scene toward the end in which Willis ties up a henchman he has seriously injured:

English: Time to take a nap, pal. [spoken with gruff, ominous tone]

Spanish voice: Don’t move, I’ll send you a doctor. [spoken apologetically]

Subtitles: Time to take a nap, pal.

Apparently the voiceover team, which might not have felt as supportive of the beat-down as Americans, saw the need to soften the tone.

There’s a mystery here I’ve only partially cracked: who created the two translations, and where? I have a faint guess that the dubbing happened in Mexico, because (1) dubbing is big there, (2) I heard the Mexicanism “güey” used (along with an inserted reference to diabetes, which is a huge problem in Mexico), and (3) the language was mostly familiar to me (I lived in Mexico for two years). Still, I would love more certainty and behind-the-scenes (hah) details.  Both translations seem to strive for Neutral Spanish, which obscures their origins. Can someone help me? Below are transcriptions I made from arbitrary parts of the movie; let me know if you notice anything!

Dubbed Subtitled
es lógico claro que sí
? bocadillos
entrando en pánico cundir el pánico
se calló el sistema falla el sistema
A trabajar! Vamos!
rastro digital huella digital
no lo creo, amigo hoy no, estatua de cera
subir (el video) cargar (el video)
soy de presión baja mi azucar en la sangre está baja
no dudaremos no flaquearemos
tenebroso escalofriante
invasión general liquidación de incendio
me importa un carajo no me importa
asesinar matar
despejar abrir
el muro la pared
hackers piratas
payasadas tonterías, linda
tarado imbécil

‘Proofiness’: The Wrong Kind of Math

In Book Review on May 4, 2011 at 12:22 am


This guy must be onto something. Look at all those fancy numbers.

Proofiness: The Dark Arts of Mathematical Deception is a lucid exposition of innumerate thinking in its many ugly forms. The author, Charles Seife, notes that a fundamental source of numerical confusion is measurement, which necessarily involves units and a degree of uncertainty stemming from the measuring instrument. Sometimes reported measurements lack units because there is no well-defined quantity to measure: what does it mean for a type of mascara to have “12 times more impact,” as L’Oreal once advertised? Sometimes people treat different units as the same, as New York politicians have done in claiming drastic improvement in their state’s educational performance based on state tests that got easier over time. Even when units are handled correctly, most people misunderstand precision.

The commonest mistake is “disestimation”–assuming an estimate is more precise than it is. Take vote counts: due to all kinds of undercounting and double-counting errors, the margin of error will be at least 2% of the total votes. That means that in cases where the difference in votes between two candidates is tiny—the 2000 presidential election especially—the logical response is to declare a tie. But ties do not sit well with most people, so closely contested elections degenerate into squabbles over hundreds of votes, as if those decisive votes were the only ones subject to error. In one of the most hilarious passages of the book, Seife chronicles the fight over one ballot in Minnesota’s close 2008 Senate race; that particular ballot offered the write-in candidate “Lizard people” but also bubbled in Al Franken for governor, leading to a heated fight among lawyers and a panel of judges about whether “Lizard people” is a valid individual (the decision: yes, he/she is).

Speaking of error, Seife devotes a chapter to undercutting most polls reported by the press. The typical opinion poll will show the percentage of people who gave each response, along with a “margin of error.” The lurking problem with these polls is that the largest source of error is not acknowledged. “Margin of error” as journalists report it is actually just statistical error due to random variation, which depends on sample size. Much more important is systematic error, skewing of the results due to the design of the survey. Examples of design problems include picking a sample that does not represent the population being studied, wording and ordering questions in a way that influences answers, and asking questions which might tempt people to lie. One blaring example of design failure is internet surveys, which can only include people with decent internet access who volunteer to take the survey based on motives that will probably skew their answers. But sadly, people will exaggerate even in careful face to face interviews—that’s why the CDC found in 2007 that heterosexual men somehow have more sexual partners than heterosexual women.

In surveying mathematical failures, Seife offers his own cutesy terminology. Sometimes I find it dull: he calls misattributed causation “causuistry,” which is neither memorable nor easy to say. Other times I found myself chuckling. He dubs fitting inappropriate lines and curves to data points “regression to the moon.” This is a play on the phrase “regression to the mean” that gets across the idea that foisting simple models onto complex data leads to wacky conclusions. Case in point: a 2004 Nature paper extrapolates a linear fit for sprinters’ times to argue that women will surpass men in the next century. Seife rejects that as ridiculous, pointing out that the same linear extrapolation would predict sprinters eventually breaking the sound barrier and surpassing the speed of light.

Proofiness is essentially a series of warnings, anecdotes, and lessons. Those three elements dance together gracefully throughout the book, making for an engaging read. So go out and find yourself a copy! Here is some more background on Proofiness if you’re not sold on the book yet:

http://well.blogs.nytimes.com/2010/10/29/the-dark-art-of-statistical-deception/

http://www.nytimes.com/2010/09/19/books/review/Strogatz-t.html

http://www.npr.org/templates/story/story.php?storyId=129972868

http://www.washingtonpost.com/wp-dyn/content/article/2010/10/08/AR2010100802980.html

Calculating Sample Variance in Python

In Personal on April 23, 2011 at 5:21 am

I am taking a break from my usual psychology antics to share some statistics-related code with the world. I wrote this Python program using standard libraries (no stats libraries) to verify that using (n-1) instead of (n) to calculate sample variance is a better long-run estimator of population variance. I’m quite sure both the code and the math is sloppy: let me know so I can refine it!

http://dl.dropbox.com/u/17834939/SampleVariance.py

(Originally, I tried pasting the code in, but I got ugly extra line breaks, so I’ve linked to the text file above).

Simplifying English Spelling? Not So Simple.

In Reality Check on February 26, 2011 at 12:30 am

Wouldn’t it be great if every letter in English spelling only made one sound? Why can’t our language be more “phonetic” like Spanish? Well it could be, but in some respects it is “too late,” and in any case our way has its perks.

To briefly make my point, here are a few practical obstacles for creating a 1:1 sound:letter script for English.

(1) Transparency of word roots is valuable. “Insane” and “insanity” have such related meanings that spelling them differently to account for pronunciation would be confusing. As another example, the silent /n/ at the end of “column, autumn, condemn” is worth keeping since it gives rise to “columnist, autumnal, condemnation.”

(2) Different spellings are helpful for reading homophones, which are common in English (though not as common as in Chinese, which needs much more meaning-specific morphemes). E.g., “eye” vs “I,” “you” vs “ewe,” “two” vs “too” vs “to.”

(3) Spelling should not reflect nuances of pronunciation that most people do not notice, such as coarticulation, assimilation, resyllabification, which change the pronunciation of words depending on spoken context. “Cap driver” would be confusing even though we only imagine pronouncing the “b” sound most of the time. Same goes for “apsurd” and for foreign accents (“do you vant some beer?”).

These ideas aren’t mine–I got them mostly from Stanislas Dehaene’s “Reading in the Brain.” It’s a cool book!

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