We could flip a coin to decide which ref to believe. But this merely gives us a decision performance which is the average of the decision performance of each individual ref. So this is no good.

We could figure out which ref is better and then always believe that ref whenever the two refs disagree. But in that case the second ref isn’t contributing anything, so we may as well just have one ref.

However, if the two refs have some estimate of their uncertainty, then we can do better. If d1 represents where ref one thinks the ball landed, and d2 represents what ref 2 thinks, and if o1 and o2 represent each ref’s report of the standard deviation of their own estimate, then the optimal way to combine both refs’ guesses into a final guess is

(d1/o1^2 + d2/o2^2) / (1/o1^2 + 1/o2^2)

which gives better performance than either ref, individually. Since we only care about whether the ball went over the line, if the line is at d=0, then this rule simplifies to testing if

d1/(o1^2) + d2/(o2^2) > 0

Is that what humans do? No. Apparently, when put together in pairs and given the chance to communicate, humans communicate both their guesses and their uncertainties, and effectively use the following formula to make a cooperative guess:

d1/o1 + d2/o2 > 0

This rule provides better performance than individual decision-making provided the difference between o1 and o2 (the uncertainties of the refs) is less than 40%. If it is more than that, this rule is worse than just having the more reliable ref make all the decisions.

Why do humans use d1/o1 + d2/o2 instead of the optimal formula, d1/o1^2 + d2/o2^2? One hypothesis is that the former is unit-free, whereas the latter requires both refs to communicate with each other in terms of (matching) spatial units.

summary:

Marc O. Ernst. Decisions Made Better (27 August 2010)
Science 329 (5995), 1022.

article:

Bahador Bahrami, Karsten Olsen, Peter E. Latham, Andreas Roepstorff, Geraint Rees, and Chris D. Frith. Optimally Interacting Minds (27 August 2010)
Science 329 (5995), 1081.

In her book Delusions of Gender (which I have not read though am intrigued to do so), cognitive neuroscientist Cordelia Fine places several modern studies of early differences in brain anatomy/function into a long line of sexist explanations for supposed differences in male and female behaviors.

The basic argument is that there has been no convincing connection made between any measured structural differences (which she argues might not exist) to behavioral differences. Just another case of correlation (maybe) and not causation.

Here’s a description of study that you might already be familiar with and Fine’s take on it:

Dr. Baron-Cohen’s lab conducted research on infants who averaged a day and a half old, before any unconscious parental gender priming. Jennifer Connellan, one of Dr. Baron-Cohen’s graduate students, who conducted the study, showed mobiles and then her own face to the infants. The results showed that among the newborns the boys tended to look longer at mobiles, the girls at faces.

Dr. Fine dismantles the study, citing, among other design flaws, the fact that Ms. Connellan knew the sex of some of the babies. Because it was her face they were looking at and she was holding up the mobile, Dr. Fine says, she may have “inadvertently moved the mobile more when she held it up for boys, or looked more directly, or with wider eyes, for the girls.”

Although I am unsure about the scientific merits, it is refreshing to see a new viewpoint in this debate. It provides some food for thought on this interesting topic:

Summarizing the research, she writes, “Nonexistent sex differences in language lateralization, mediated by nonexistent sex differences in corpus callosum structure, are widely believed to explain nonexistent sex differences in language skills.”

What all this adds up to, she says, is neurosexism. It’s all in the brain.

Just last night, I watched the tense but amazing film The Hurt Locker (don’t let the name disuade you, see the phenomenal Metacritic rating), which is about a bomb disposal squad during the recent Iraq War. There is one particularly stirring scene with a suicide bomber who claims that he was forced to wear a vest with explosives and doesn’t want to go through with it. The difficulty in the limited time before the bomb explosion revolves around whether to actually trust the man and the challenge of trusting someone when neither party speaks the other’s language. You can certainly at least understand (putting aside the ethics of war itself) why governments are interested in detecting nonverbal trust cues.

Details about the IARPA call for proposals are after the jump.

IARPA is soliciting submissions on the following areas aimed at
addressing the challenges of defining, understanding, and ultimately
detecting valid, reliable signatures of trust in humans:

1.) Different kinds of trust and what, if any, kinds of
neurophysiological signals might be associated with them. IARPA seeks
to understand the different manifestations that trust may take (i.e.
swift trust, conditional trust, unconditional trust, etc.) as well as
the different neurophysiological processes associated with one or more
of these kinds of trust.

2.) New models of neural systems and patterns of neural activation
related to different kinds of trust and associated neurophysiological
signatures of those activation patterns. IARPA seeks to understand the
degree to which the neural-bases of trust(s) may assist in detecting
peripheral signals of trust and trustworthiness under different
conditions.

3.) Potentially novel preconscious signals or combinations of signals
- neural, endocrine, physiological, behavioral, etc. – that may be
indicative of trust or trustworthiness among people in different
contexts. IARPA seeks to elucidate signals and neurobiological
processes that humans may use for assessing trust, but which are not
yet – or are currently poorly – understood.

4.) New sensor technologies or combinations of technologies that can
assist in detecting subtle but valid and reliable changes in
neurophysiological states that may be indicative of trust among
humans. IARPA seeks to explore the feasibility of using technology to
amplify systems that humans have evolved to preconsciously assess
trust in others.

5.) Novel, ecologically-valid, but ethical “trust-based” protocols
designed to assess the validity and reliability of potential trust
signals among two or more humans. IARPA seeks to develop new, more
sophisticated processes for understanding near real-time human
preconscious assessment of trust in near real-world circumstances.

It is nice how YouTube can be both educational and entertaining!

Case No. 158

An attractive, amiable boy from a working-class background, you struck the study staff as happy, stable, and sociable. “My general impression is that this boy will be normal and well-adjusted—rather dynamic and positive,” the psychiatrist reported.

After college, you got an advanced degree and began to climb the rungs in your profession. You married a terrific girl, and you two played piano together for fun. You eventually had five kids. Asked about your work in education, you said, “What I am doing is not work; it is fun. I know what real work is like.” Asked at age 25 whether you had “any personal problems or emotional conflicts (including sexual),” you answered, “No … As Plato or some of your psychiatrists might say, I am at present just ‘riding the wave.’” You come across in your files as smart, sensible, and hard-working. “This man has always kept a pleasant face turned toward the world,” Dr. Heath noted after a visit from you in 1949. From your questionnaire that year, he got “a hint … that everything has not been satisfactory” at your job. But you had no complaints. After interviewing you at your 25th reunion, Dr. Vaillant described you as a “solid guy.”

Two years later, at 49, you were running a major institution. The strain showed immediately. Asked for a brief job description, you wrote: “RESPONSIBLE (BLAMED) FOR EVERYTHING.” You added, “No matter what I do … I am wrong … We are just ducks in a shooting gallery. Any duck will do.” On top of your job troubles, your mother had a stroke, and your wife developed cancer. Three years after you started the job, you resigned before you could be fired. You were 52, and you never worked again. (You kept afloat with income from stock in a company you’d done work for, and a pension.)

Seven years later, Dr. Vaillant spoke with you: “He continued to obsess … about his resignation,” he wrote. Four years later, you returned to the subject “in an obsessional way.” Four years later still: “It seemed as if all time had stopped” for you when you resigned. “At times I wondered if there was anybody home,” Dr. Vaillant wrote. Your first wife had died, and you treated your second wife “like a familiar old shoe,” he said.

But you called yourself happy. When you were 74, the questionnaire asked: “Have you ever felt so down in the dumps that nothing could cheer you up?” and gave the options “All of the time, some of the time, none of the time.” You circled “None of the time.” “Have you felt calm and peaceful?” You circled “All of the time.” Two years later, the study asked: “Many people hope to become wiser as they grow older. Would you give an example of a bit of wisdom you acquired and how you came by it?” You wrote that, after having polio and diphtheria in childhood, “I never gave up hope that I could compete again. Never expect you will fail. Don’t cry, if you do.”

What fascinates me is the absolute novelty of this kind of data. Normally, when someone relates their “life story,” we willingly participate in something of a shared lie. Both listener and story-teller know that the “life story” is being told in hindsight: Memory is not perfect and humans sometimes (often, perhaps) add meaning and create unifying themes in stories where they may be none. We emphasize the good parts and try to forget the not-so-good parts. In a sense, history recounted is never truly veridical but instead tainted with everything that happened after. Which is precisely why the availability of an objective history than spans an entire lifetime (or, as objective as possible) of both a qualitative (interview) and quantitative (medical) nature is so novel.

As you might expect, the data is confusing and hard conclusions are not easy to come by. There are however some tangible factors that seemed to correlate/predict success in life, which I’ve included after the jump. What predicts success in life? What predicts failure?

What allows people to work, and love, as they grow old? By the time the Grant Study men had entered retirement, Vaillant, who had then been following them for a quarter century, had identified seven major factors that predict healthy aging, both physically and psychologically.

Employing mature adaptations was one. The others were education, stable marriage, not smoking, not abusing alcohol, some exercise, and healthy weight. Of the 106 Harvard men who had five or six of these factors in their favor at age 50, half ended up at 80 as what Vaillant called “happy-well” and only 7.5 percent as “sad-sick.” Meanwhile, of the men who had three or fewer of the health factors at age 50, none ended up “happy-well” at 80. Even if they had been in adequate physical shape at 50, the men who had three or fewer protective factors were three times as likely to be dead at 80 as those with four or more factors.

What factors don’t matter? Vaillant identified some surprises. Cholesterol levels at age 50 have nothing to do with health in old age. While social ease correlates highly with good psychosocial adjustment in college and early adulthood, its significance diminishes over time. The predictive importance of childhood temperament also diminishes over time: shy, anxious kids tend to do poorly in young adulthood, but by age 70, are just as likely as the outgoing kids to be “happy-well.” Vaillant sums up: “If you follow lives long enough, the risk factors for healthy life adjustment change. There is an age to watch your cholesterol and an age to ignore it.”

The study has yielded some additional subtle surprises. Regular exercise in college predicted late-life mental health better than it did physical health. And depression turned out to be a major drain on physical health: of the men who were diagnosed with depression by age 50, more than 70 percent had died or were chronically ill by 63. More broadly, pessimists seemed to suffer physically in comparison with optimists, perhaps because they’re less likely to connect with others or care for themselves.

There is also a nice video of the George Valliant (who has run the study for the last 40 years) along with the article.

Other training videos from the same trainer are available along with an official website with interesting tips about mouse training. Perhaps highly inbred lab mice are unable to replicate such feats but it is amazing to see in what detail this trainer understands mouse behavior and development:

An absolute necessity for any pet training is to understand the animal’s needs and to know about its generic behaviour, since appropriate animal training is only based on certain natural habits. For mouse agility, this means e.g. their great spatial orientation abilities and spatial memory which is worth bringing to light by relevant trick training. In nature, mice always prefer the familiar (= safe) route to their feeding site, no matter if it’s a long way round. This is also the reason why mice are unbeatable in maze tests – and a mouse agility course is nothing else than a maze without walls!
But many owners forget that if you expect your pet to show some natural habits and abilities, first and foremost the husbandry has to be species-appropriate. If your mice have to live in a small ground level cage, their three-dimensional consciousness and orientation abilities will surely be stunted or never fully develop.

Two amazing things here:

1. Plants missing photosynthetic enzymes of their own that migrate directionally toward “victim” plants. This behavior has an uncanny resemblance to axon guidance. Make sure to view the time-lapse video in the NYT article. Here’s an image from the PSU website:
   
   
2. Plants capable of identifying kin and “being nice” to kin while going into a competitive mode of root growth with non-kin. Amazing.

It refreshing to see this kind of interesting behavior without any neurons involved. It makes me think (realize) that the idea of a neuron or a neural system has many components and there might not be any good reason to assume that a single cell must have all of those properties or none of them. Something like a neuron-like cell that’s not a neuron in the classical sense. Anyone know of other examples?

The concept that the brain holds maps of the surface of the body in the primary sensory and motor cortex is a fascinating but well known fact to the field of neuroscience since the early work of Wilder Penfield. What is less broadly appreciated is the concept of “peripersonal space”. A new book by Sandra and Matthew Blakeslee describes peripersonal space in the following way:

The maps that encode your physical body are connected directly, immediately, personally to a map of every point in that space and also map out your potential to perform actions in that space. Your self does not end where your flesh ends, but suffuses and blends with the world, including other beings. [...] Your brain also faithfully maps the space beyond your body when you enter it using tools. Take hold of a long stick and tap it on the ground. As far as your brain is concerned, your hand now extends to the tip of that stick. [...] Moreover, this annexed peripersonal space is not static, like an aura. It is elastic. [...] It morphs every time you put on or take off clothes, wear skis or scuba gear, or wield any tool. [...] When you eat with a knife and fork, your peripersonal space grows to envelop them. Brain cells that normally represent space no farther out than your fingertips expand their fields of awareness outward, along the length of each utensil, making them part of you.

What I appreciate about this, besides the stretchy comic book characters that it makes me think about, is that it provides a powerful perspective to begin piecing together a mass of disparate neuroscience data, which the Blakeslee’s capitalize on.

You’ll recognize the name Sandra Blakeslee from her co-authorship with Jeff Hawkins in On Intelligence and with V.S. Ramachandran in Phantoms in the Brain. This new book continues in the spirit of illustrating the broader significance of surprising findings in neuroscience. It covers a lot of recent neuroscience research, including mirror neurons, place cells and grid cells, the insular cortex and neuroprosthetics. For anyone looking to get the quick picture of these frontier research areas, this book serves as an excellent primer. It does an excellent job of making connections to socially relevant topics such as the secrets of athletic excellence, underlying causes of eating disorders and the modern obsession with plastic surgery. I have come to believe that neuroscience will eventually provide concrete explanations for the metaphors we use and the spooky phenomena we believe in but science cannot prove. Along those lines, this book does a great job of describing brain mechanisms that may underly paranormal phenomena like auras and out-of-body experiences.

One of my favorite parts is chapter six, a short chapter with a Phantoms in the Brain feel that presents some extremely jarring clinical examples of neurological problems potentially caused by body map disorders. It describes cases of individuals who want to have their limbs amputated because they feel like they don’t belong to them, individuals who no longer get feedback from their limbs as if they have disappeared, as well as cases of one woman who felt like she had three arms and three legs. That these cases exist are fascinating in their own regard; that there exists a systems-level conceptual framework with which we might understand the underlying causes for them is utterly incredible.

The implications of these ideas to AI are significant. What kinds of intelligent systems can we build by assuming that they have ego-centric representations of objects in their peripersonal space, or by assuming that their motor intentions are tickled by watching the movements of other creatures? The implications for computational neuroscience are also significant. What kind of system of neuronal processors is capable of producing cells that are sensitive to peripersonal space? What information must flow into those cells, and where is that information available from in the brain? Along what channels and using which “algorithms” does your brain map the visual information of a person moving their limbs to the motor areas that control your limbs? Perhaps I’ll be able to read about these things in the next Blakeslee neuroscience tour de force.

The Body Has a Mind of Its Own: How Body Maps in Your Brain Help You Do (Almost) Everything Better
by Sandra Blakeslee (Author), Matthew Blakeslee (Author)
Random House Publishing Group

(Full disclosure: Sandra Blakeslee and Random House kindly sent us a copy of the book to review before their release date…thanks guys!)

…brainwashing their youth

• Vergoz et al, 2007, Science
• commentary

…and/or mysteriously disappearing from the face of the earth

• Colony Collapse Disorder

Keeping an eye on species poised to take over the world,
Davie