Reading makes you stronger

The first Alzheimer’s diseased brain I ever touched looked horrific. The cortex was shriveled, the ventricles were large, cavernous voids, and when I stained the sample I saw a galaxy of proteinaceous tangles and masses. The brain had clearly been degenerating steadily for over a decade, and it was difficult to imagine how the patient could have functioned. I was shocked to discover that, according to his charts, the patient’s dementia had only been detectable for a few years. In contrast, certain brains I analyzed appeared much more intact, yet came from patients who had suffered from severe dementia for over a decade.

These patients exemplify the dramatically different ways people can respond to neurodegenerative changes. Even when confronted with the same disease and comparable severity, people vary considerably in the extent of cognitive decline. Specifically, people with higher levels of education and occupational attainment are more successful at coping with the same amount of brain damage and degeneration.

One hypothesis that accounts for this discrepancy is the concept of cognitive reserve. The cognitive reserve hypothesis posits that people who have challenged their minds for significant portions of their lives (i.e. they didn't just start playing Sudoku at the age of 60) can compensate for neural deficits by recruiting alternate brain networks as backup or “reserve.” In support of this hypothesis, functional brain imaging shows that "high-functioning" older adults activate significantly more areas of their brains than both "low-functioning" older adults and young adults when performing certain cognitive tasks. This indicates neural compensation; the "high-functioning" old engage in alternative neural strategies in response to neural deficits or declines in cognitive abilities. Importantly, this type of compensation may be facilitated by a more flexible organization of the brain, which results from early cognitive experience.

Of course, people who did not start challenging themselves until later in life should not despair. Other requisites of compensation, such as plasticity (including the birth new neurons and enhanced signaling between existing neurons), may be improved by cognitive experience throughout life (although the earlier the better). And in a complementary aspect of cognitive reserve, people who challenge their brains throughout life may be able to protect their existing brain networks. Intellectually stimulating activities may increase the efficiency and capacity of these networks, enabling them to withstand a greater degree of age-related change while maintaining intact functioning (again, the earlier the better).

The cognitive reserve hypothesis has recently been supported by findings of Dr. Margit Bleecker, who studied the effects of lead exposure on cognitive function. The study involved 112 lead smelter workers in New Brunswick, who were divided into groups with high reading ability (12th grade or higher) and low reading ability (11th grade or lower). Reading ability is a recognized measure of cognitive reserve, and is perhaps a better metric than education and occupation (e.g. it distinguishes self-taught individuals who dropped out of school for economic reasons from people who graduated high school but are functionally illiterate). Importantly, although lead exposure has negative effects on many brain functions, well-ingrained functions like reading ability are resistant to the consequences.

Both groups had similar lead exposure, age, alcohol use, and depression levels, but those with high cognitive reserve performed 2.5 times better on cognitive tests than those with low cognitive reserve. In contrast, cognitive reserve did not protect motor speed and dexterity from the toxic effects of lead, indicating that other parts of the workers’ nervous systems were still vulnerable. These findings, published in Neurology, demonstrate that cognitive reserve protects against the cognitive effects of chronic lead exposure.

The key to cognitive reserve is not to wait until you’re in your 60s (or even 50s, 40s, 30s, or 20s, for that matter), but to challenge yourself intellectually as early and often as possible. So read, play "brain games," play soccer, and do all the other wonderfully fun and exciting things that are good for you.

UPDATE: For more information on cognitive reserve, see posts by Michael Merzenich of Posit Science and Alvaro of SharpBrains.

My brain and my ACL

My life, though generally fortunate, has been peppered by a small number of somewhat serious injuries: broken hand, broken collarbone, broken wrist, torn meniscus, ruptured anterior cruciate ligament (ACL). The hand and collarbone were consequences of my big sister tripping and crushing me, respectively, but the rest I managed to accrue on my own. (Even though I sustained these latter injuries on the soccer field, I was unaccompanied by the touch of another player).

My mom always insisted that my proclivity for injury was due to the intrinsic grace of my bones and joints—"elegant and delicate, like a bird!"—but a recent study in the June edition of the American Journal of Sports Medicine suggests something different is to blame: my brain.

From the University of Delaware News:

A torn anterior cruciate ligament (ACL) is among an athlete's most-dreaded injuries, often requiring surgery and months of rehab, as has been the case with Philadelphia Eagles quarterback Donovan McNabb. While being tackled in football or hurtling into an embankment on an icy ski course can tear this major knee ligament, most athletes actually “do themselves in”--they don't collide with a person or object, they end up injuring themselves when they land off-balance during a jump or run.

“We had some data from previous research which suggested that these noncontact knee injuries occur when a person gets distracted or is 'caught off guard,'“ Charles Buz Swanik, the UD assistant professor of health sciences who led the study, said. These awkward movements have the biomechanical appearance of a knee buckling, but can be reproduced safely in the lab to study how people mentally prepare and react to unanticipated events.

Based on my personal experiences, the connection between sport-induced injury and distraction is not surprising. Both my wrist and my ACL/meniscus injuries (the latter being a simultaneous double-whammy) occurred while I wasn't particularly focused on the games. In both situations, I was slightly anxious because these were the only two soccer games my dad had attended since I was 10 (one in high school (wrist), one in college (knee)). Further, I was not involved in the plays that immediately preceded my injuries; it was precisely when ball unexpectedly approached, summoning my mildly reluctant participation, that my "delicate" limbs met with disaster.

But Swanik believes these momentary lapses in attention are indicative of more extensive deficiencies.

“This made me wonder if we could measure whether these individuals had different mental characteristics that made them injury-prone,” Swanik said.

To identify subjects for their study, the researchers administered neurocognitive tests to nearly 1,500 athletes at 18 universities during the preseason. This testing also provided baseline data for athletes who might sustain a concussion after the season started, Swanik said.

Visual memory, verbal memory, processing speed, and reaction time all were assessed.

...

In analyzing the data, the scientists found that the athletes who ended up with noncontact ACL injuries demonstrated significantly slower reaction time and processing speed and performed worse on visual and verbal memory tests when compared to the control group.

As Swanik writes in his report, "physical activity requires situational awareness of a broad attentional field to continuously monitor the surrounding environment, filter irrelevant information, and simultaneously execute complex motor programs. Increased arousal or anxiety changes an athlete's concentration, narrows their attentional field, and alters muscle activity, which has been associated with poor coordination and inferior performance."

These conclusions remind me of one of David Foster Wallace's essays in Consider the Lobster, "How Tracy Austin Broke My Heart." Wallace devotes this essay to the devastating contrast between Tracy Austin's brilliance on the tennis court (both physical and mental) and her abominable ability to intellectualize her experiences in her memoir. He ultimately concludes that the vacuity and lack of insight of sports memoirs, such as hers, is inextricably linked to the qualities that lead to great athletes in the first place.

Their ability to maintain exceptional focus under the scrutiny of thousands of viewers (including their parents), makes them incapable of an appreciation of their athletic genius, and thus of significant insight into its nature. During games that are crucial to the careers to which they have been devoted since childhood, they manage to "invoke for themselves a cliché as trite as 'One ball at a time' or 'Gotta concentrate here,' and mean it and then do it." Meanwhile, if the rest of us were under such circumstances, we would founder and crumple and fail precisely because we think too much about matters that have nothing to do with the direction and velocity of the ball, or the appropriate bending of the knee during complicated, high-velocity movements.

As Wallace writes, "those who receive and act out the gift of athletic genius must, perforce, be blind and dumb about it—and not because blindness and dumbness are the price of the gift, but because they are its essence." (Their vastly superior speed, strength, and visual acuity probably isn't trivial).

Another major risk factor for ACL injuries is gender. Girls are four to eight times more likely to tear or rupture their ACLs than men, with female soccer and basketball players at the highest risk. There are a few theories as to why this gender difference exists: 1) bone alignment of the pelvis/femur/tibia create excess stress on the ACL; 2) female hormones relax ligaments, muscles and joints, making joints more flexible and prone to injury; 3) as girls pass through adolescence, their muscular control of the knee may not keep up with their skeletal growth.

To incorporate Swanik's conclusion with the gender discrepancy, female hormones can also result in concentration deficits, which may result in a sub-optimal state of arousal in a given athletic situation. In any case, this study has interesting implications for injury prevention. Not only should female athletes stop running like girls, but perhaps cognitive exercises that train processing speed and reaction time may also benefit the accident prone.

Humans to the rescue

Images like the one above are familiar to any of us who have ever used webmail, Ticketmaster, or any other web service that wants to prevent automated spammers and scalpers from exploiting their systems. The distorted, fuzzy letters don't provide a challenge to humans, but are indecipherable to the most sophisticated computer algorithms. Our genius is facilitated by our "invariant" perceptual abilities; that is, we can recognize objects, faces, and letters independent of rotation, translation, and scale.

However, these CAPTCHAs (Completely Automated Public Turing Test to Tell Computers and Humans Apart) were designed with a wonderfully clever ulterior motive. In addition to preventing rogue bots from devastating our virtual lives, CAPTCHAs like the one above are actually exploiting you, the human, and the invariance of your human perception, to help digitize the world. The words presented in these CAPTCHAs are pulled from the book-scanning project of the Internet Archive, which aims to scan millions of public-domain books and put them online for free. One word of the CAPTCHA is known to the computer, and is used to verify your humanness, while the other was indecipherable to the Archive's scanners. When you type in that word, you're actually translating the image into text for the Archive.

There's a fantastic article in Wired Magazine about this type of "human computation," "the art of using massive groups of networked human minds to solve problems that computers cannot." The article profiles the work of Luis von Ahn, who designs clever ways to harness the powerful brains of bored web surfers to solve computing problems (e.g. judging random pictures as "pretty," tagging images and audioclips, etc.)

From Wired Magazine:

If people could so easily recognize pictures of letters and numbers, could [they] use this ability to identify and label the vast number of images on the Web?

...

The way to do it, he realized, was as a game. It would pull images off the Web, then randomly pair two players from around the world. They would be shown the same images, then each would type in as many words as they could to describe those images, hoping to hit upon the same ones as their anonymous partner. They'd get 50 points for each match, and two and a half minutes to earn as many points as possible. Von Ahn suspected that whenever the players agreed on a word — "meadow" to describe a tree-lined clearing, for example — they would be choosing a highly accurate label for the picture.

Von Ahn cobbled the game together in a week — "crappy, totally terrible code," he admits — and threw it online. He dubbed it The ESP Game and emailed the URL to a few friends. Within days it was Slashdotted, whereupon his server nearly crashed under the load of new players. Astonished, von Ahn watched for the next four months as 13,000 players produced 1.3 million labels for some 300,000 images — with a few hardcore fans clocking more than 50 hours of play. "It's like crack," as one player complained in an email to von Ahn. The labels his players generated were far more accurate than what other image-search technologies produced. Most search engines are limited to sniffing out words associated with a picture, such as the name given to the image, words in the page around it, or links pointing to it. That's inherently imprecise: When von Ahn recently searched for "dog" on Google, a third of the pictures showed no dogs at all. When he queried the ESP database, almost all the results contained canines. Better yet, players often generated labels that were subtle and nuanced. A search for "funny" found a picture of Ronald McDonald being hauled away by police and one of Queen Elizabeth picking her nose.

Even the DHS wants to employ your brainpower as you procrastinate on the web:

This spring, von Ahn got a call from the Department of Homeland Security. He went to Washington to meet with DHS officials, and together they devised a game in which people are challenged to find dangerous objects in images of x-rayed baggage. The pictures would be fed from airport scanners, and players would act as a second set of eyes for overtaxed security employees. If enough players noticed something amiss, an alert would be triggered.

Von Ahn's other games that capitalize on human superiority (supposedly available at Games with a Purpose "in July," but as of now the site isn't running yet) include:

1) Matchin' Players are shown the same pair of images, then each tries to pick the one they'll both agree is more attractive. Creates a database of images searchable by aesthetic value, a task no algorithm can perform.

2) Babble Two English-speaking players are shown a sentence in a foreign language that neither of them speak. A list of possible English meanings appears below each word. Players try to agree upon a set of English words that forms the most coherent sentence. Translates foreign text into English without requiring anyone fluent in both languages.

3) InTune Players listen to the same audioclip and then try to come up with the same phrase to characterize it. Tags sounds with searchable descriptive text.

4) Squigl Two players are shown the same picture and a word describing an element within the image (e.g., a picture of a dog and the word "leash"). They each draw a border around the element. Produces a set of pictures with their internal components tagged — terrific for very specific image searches.

5) Verbosity One player is given a word, and the other tries to guess that word by completing phrases such as "It is near a ____" or "It is a type of ____." The first player answers "true" or "false" but can't use the word itself. Creates a database of commonsense knowledge describing the objects.

Link to the full Wired article.

New and improved robot CPGs

In my first post ever, I discussed how specialized circuits in the spinal cord (called "central pattern generators," or CPGs) coordinate the intricate motions and muscle patterns involved in running and walking, without significant input from the brain. The autonomy of these circuits allows animals to run and walk while their mental efforts are otherwise engaged; for example, we can talk on the phone while walking to dinner, and decapitated chickens can still run away.

One of the most important features of CPGs is their adaptability. Whether running through a forest, walking on an oily surface, or dribbling a soccer ball, we need to continuously modify our movements. Thus, as opposed to generating rigid action patterns, CPGs provide a flexible template for coordinating our muscles and various joints. This template interacts with sensory information, allowing us to elegantly adapt to our unpredictable world. Flexibility, however, poses a challenging computational problem; not only must we decipher how circuits of neurons coordinate hundreds of muscles, but also how their output can be refined by incoming sensory information.

Without understanding these fundamental issues, it is difficult to produce machines that can move as intelligently as we. Honda's ASIMO, "The World's Most Advanced Humanoid Robot," is capable of executing an astounding range of human-like movements (running, walking smoothly, reaching for objects), but has previously stumbled and fallen down stairs. A recent article in PLoS Computational Biology describes a new and improved droid named RunBot, which is capable of adapting to unfamiliar terrain in an animal-like way.

Although not nearly as cute as ASIMO, RunBot's motor circuitry is more "intelligent" (i.e. more human). As I mentioned in my earlier post, the motor system is arranged in a hierarchy: the "higher" control centers give the signal to initiate a movement, recruiting the "lower" CPGs to take care of the details. These lower circuits respond to the environment reflexively, incorporating localized feedback to generate intricate adjustments in muscle tone. This responsiveness allows us to immediately compensate for small perturbations, such as unnoticed rocks on a trail. When we need to significantly modify our gait, however, such as stepping over a baby, we must enlist the higher centers, which will generate more dramatic modifications to the CPGs.

ASIMO lacks this hierarchy, requiring it to continuously calculate the position and motion of every joint. RunBot, however, has been engineered with several levels of control, allowing it to adapt to changes in terrain in a more computationally efficient manner. RunBot interprets the environment with an infrared sensor, which communicates with the lower circuits to regulate their activity. Thus, when RunBot encounters an alteration to its terrain and becomes unbalanced, this sensor modifies the pattern of the lower circuits, allowing the bot to change its gait.

However, like humans, RunBot must learn how to modify its movements with respect to sensory input. When we learn how to walk, our brains "train" our CPGs until they can execute the movement relatively independently. These same mechanisms come into play when a runner learns to hurdle or a soccer player learns a new move; these behaviors initially require significant concentration, but with practice can be executed with little mental effort. To replicate this learning process, RunBot's circuitry includes, according to the authors, "online learning mechanisms based on simulated synaptic plasticity." Thus, when RunBot first attempts to climb a slope, it falls over like poor ASIMO. With trial and error, however, its circuitry learns to properly compensate for the relevant sensory input, shortening and slowing its steps just like a human.

Why are blondes more attractive than brunettes?

As a young brown-eyed, brown-haired girl growing up in Orange County, CA, I found this "stereotype" repeatedly, bewilderingly, validated. Although I defended myself with Van Morrison and a sizeable artillery of blonde-jokes, behind my façade of self-assurance I continued to wonder: why are blonde hair and blue eyes "prettier"? Now, as a slightly more mature brunette with a more comprehensive understanding of natural selection, I still find the question intriguing. Why did Europeans evolve to prefer blonde hair and blue eyes? What do these features indicate about health and fertility?

Psychology Today has an excerpt from the book Why Beautiful People Have More Daughters, by Alan S. Miller and Satoshi Kanazawa, which explores "Ten Politically Incorrect Truths About Human Nature," including the mystery of the "blonde bombshell":

Long before TV—in 15th- and 16th- century Italy, and possibly two millennia ago—women were dying their hair blond. Women's desire to look like Barbie—young with small waist, large breasts, long blond hair, and blue eyes—is a direct, realistic, and sensible response to the desire of men to mate with women who look like her. There is evolutionary logic behind each of these features.

Blond hair is unique in that it changes dramatically with age. Typically, young girls with light blond hair become women with brown hair. Thus, men who prefer to mate with blond women are unconsciously attempting to mate with younger (and hence, on average, healthier and more fecund) women. It is no coincidence that blond hair evolved in Scandinavia and northern Europe, probably as an alternative means for women to advertise their youth, as their bodies were concealed under heavy clothing.

Women with blue eyes should not be any different from those with green or brown eyes. Yet preference for blue eyes seems both universal and undeniable—in males as well as females. One explanation is that the human pupil dilates when an individual is exposed to something that she likes. For instance, the pupils of women and infants (but not men) spontaneously dilate when they see babies. Pupil dilation is an honest indicator of interest and attraction. And the size of the pupil is easiest to determine in blue eyes. Blue-eyed people are considered attractive as potential mates because it is easiest to determine whether they are interested in us or not.

The irony is that none of the above is true any longer. Through face-lifts, wigs, liposuction, surgical breast augmentation, hair dye, and color contact lenses, any woman, regardless of age, can have many of the key features that define ideal female beauty. And men fall for them. Men can cognitively understand that many blond women with firm, large breasts are not actually 15 years old, but they still find them attractive because their evolved psychological mechanisms are fooled by modern inventions that did not exist in the ancestral environment.

The article also explains why men prefer women with small waists and large breasts (both are correlated with levels of estrogen and progesterone, indicating greater fecundity), why beautiful people have more daughters (physical attractiveness is more important for girls than boys, and parents can bias the sex ratio depending on the traits they can offer), why men sexually harass women (it's about respect), and why most suicide bombers are Muslim (the 72 virgins waiting patiently in heaven aren't trivial). Some of the hypotheses are a little dubious to me, but it's an interesting read nonetheless.

Link to the article.

Williams Syndrome and human sociality

There's a great article by David Dobbs in the New York Times Magazine about Williams Syndrome (WMS), a condition with a diverse and remarkable array of cognitive symptoms. I have vivid memories of my first exposure to WMS--watching a documentary hosted by Oliver Sacks for my "Psychology of Music" class. In one of the first scenes, Dr. Sacks introduces himself to a 6-year old girl with WMS, who eagerly and cheerfully insists "Don't be shy, Mr. Sacks." In another scene he takes her to a sandwich shop, where she enthusiastically engages the employees and fellow customers in conversation, offering hugs to all within reach. This behavior exemplifies one of the most remarkable endowments of children with WMS--endearing, socially fearless personalities, marked by extreme gregariousness and emotional empathy.

This charm is facilitated by a peculiarly rich vocabulary and proficiency with language; for example, when asked to name some animals, a WMS child responded "Brontosaurus, tyranadon, brontasaurus rex, dinosaurs, elephant, dog, cat, lion, baby hippopotamus, ibex, whale, bull, yak, zebra, puppy, kitten, tiger, koala, dragon..." quickly and fluidly naming exotic (though occasionally non-existent) animals as if reading them off a list. When striking conversations with strangers, they are extremely loquacious, to the point where they appear to burden the listener with verbosity.

Adding to the list of aptitudes of WMS people is a great affinity for music (hence learning about the condition in my "Psychology of Music" class). People with WMS can have savantlike musical skills, and those without notable musical gifts nevertheless feel "drawn" to music, an inclination likely aided by an acute sensitivity to sound. One scene of the documentary featured WMS children walking through the woods, commenting on how loud the bees and rustling leaves were (sounds which were more or less unnoticed by Sacks).

These remarkable virtuosities with language, social interaction, and music are accompanied, however, by profound cognitive impairments. The average IQ of a person with WMS is in the 60's, and the vast majority cannot live independently. Despite their seeming fluency with verbal communication, people with WMS have poor language comprenension, incapable of understanding the underlying meaning of most conversations. Their communication, though voluminous, lacks depth and subtlety, and rarely goes beyond "small talk."

This intriguing disconnect pervades social interactions beyond spoken language; in spite of their gregariousness, people with WMS often fail to grasp social cues, including facial expression and body language. Moreover, the extreme geniality of WMS people is indicative of an underlying problem: a complete lack of social fear. According to the article, "functional brain scans have shown that the brain’s main fear processor, the amygdala, which in most of us shows heightened activity when we see angry or worried faces, shows no reaction when a person with Williams views such faces. It’s as if they see all faces as friendly."

Children with WMS also have significant deficiencies in spatial processing and dealing with numbers. In another memorable scene from the documentary, Sacks presents the child with a plate of muffins, asking her how many she thought were on the plate. "3," she immediately and eagerly replied. There were clearly over 10. When then asked to make a + shape out of four rectangular pieces, she arranged them haphazardly, seemingly at random, at which point she cheerfully announced "Done!"

WMS thus provides a captivating mélange of cognitive strengths and weaknesses. Unlike most forms of mental retardation, in which most or all cognitive abilities are concurrently impaired, the distinct peaks and valleys of aptitudes in WMS allows a dissociation between specific abilities and "general intelligence." Further, the genetic basis of WMS is known: it arises from a deletion of ~28 known genes from chromosome 7. Thus, WMS offers a tantalizing opportunity to understand the genetic influences on complex brain functions, which I plan to explore in a future post.

This post, however, was inspired by a separate, equally captivating story woven by the WMS condition: the implications for human social behavior. Why, despite their affability and charm, do WMS people find it hopelessly difficult to make friends? According to Dobbs, this paradox "makes clear that while we are innately driven to connect with others, this affiliative drive alone will not win this connection. To bond with others we must show not just charm but sophisticated cognitive skills."

So why is it that all our relationships, even casual friendships, demand intelligence? Why was it so difficult to believe that Jenny would marry Forrest Gump? The article broaches two related and overlapping evolutionary theories, the "social brain" theory and the "Machiavellian-intelligence" theory. These theories propose, respectively, that humans evolved large brains to generate complex social relationships, and that deception and manipulation (and the ability to identify these two behaviors) are necessary to successfully compete amongst other members of society. Thus, as Steven Pinker suggests in The Language Instinct, "human evolution was propelled more by a cognitive arms race among social competitors than by mastery of technology and the physical environment."

Social life presents a convoluted tension, involving (as stated by Ralph Adolphs and quoted by Dobbs), a “complex and dynamic interplay between two opposing factors: on the one hand, groups can provide better security from predators, better mate choice and more reliable food; on the other hand, mates and food are available also to competitors from within the group.” Thus, our survival is contingent on a delicate balance between getting along with others and outperforming them. Requisite for maintaining this balance is a comprehensive understanding of subtle and complicated social dynamics, enabling both manipulation and the detection of manipulation by others. Dobbs writes that:

"People with Williams, however, don’t do this so well. Generating and detecting deception and veiled meaning requires not just the recognition that people can be bad but a certain level of cognitive power that people with Williams typically lack. In particular it requires what psychologists call “theory of mind,” which is a clear concept of what another person is thinking and the recognition that the other person a) may see the world differently than you do and b) may actually be thinking something different from what he’s saying.

...it’s clear that Williamses do not generally sniff out the sorts of hidden meanings and intentions that lie behind so much human behavior."

The article concludes with a fascinating question about being human: is our social behavior driven more by the urge to connect or the urge to manipulate the connection? Are we trying to make friends, or do we only care about being genetically more successful than our peers?

"We dominate the planet because we can think abstractly, accumulate and relay knowledge and manipulate the environment and one another. By this light our social behavior rises more from big brains than from big hearts.

...

The disassociation of so many elements in Williams — the cognitive from the connective, social fear from nonsocial fear, the tension between the drive to affiliate and the drive to manipulate — highlights how vital these elements are and, in most of us, how delicately, critically entwined. Yet these splits in Williams also clarify which, of caring and comprehension, offers the more vital contribution. For if Williams confers disadvantage by granting more care than comprehension, reversing this imbalance creates a far more problematic phenotype.

As Robert Sapolsky of the Stanford School of Medicine puts it: “Williams have great interest but little competence. But what about a person who has competence but no warmth, desire or empathy? That’s a sociopath. Sociopaths have great theory of mind. But they couldn’t care less.”"

Link to the NYTM article.

Babies: cheating bastards

From The Globe and Mail:

Babies aren't as innocent as they look, according to new research out of the United Kingdom.

Sweet little infants actually learn to deceive before they can talk, says University of Portsmouth psychology department head Vasudevi Reddy in a study that challenges traditional notions of innocence while confirming many parents' suspicions about their sneaky babies.

Most psychologists have believed that children cannot really lie until about four years of age. But after dozens of interviews with parents, and years spent observing children, Dr. Reddy has determined that infants as young as seven months are quite skilled at pulling the wool over their parents' eyes.

Fake crying and laughing are the earliest and most common forms of deception, but as babies continue to develop their skills of subterfuge, they become far more calculating.

There was the 11-month-old who, caught in the act of reaching for the forbidden soil of a house plant, quickly turned his outstretched hand into a wave, his mother reported to Dr. Reddy, "as though he was saying, 'Oh, I wasn't really going to touch the soil, Mom, I was waving at you.' "

Babies also seem to think they are masters of the Jedi mind trick, using steady eye contact as a distraction technique. Another 11-month-old, upon being presented with toast she didn't want to eat, would hold eye contact with her mother while discreetly chucking the toast onto the floor.

"She's very sneaky," the mother told Dr. Reddy, "she thinks you can't see it."

Via OmniBrain.