Cognitive Daily reports nearly every day on fascinating peer-reviewed developments in cognition from the most respected scientists in the field.
Greta Munger is Associate Professor of Psychology at Davidson College whose works include The History of Psychology: Fundamental Questions. Dave Munger is a writer whose works include Researching Online and The Pocket Reader. And yes, he is married to Greta.
The average 3- to 10-year-old girl in the U.S. owns eight Barbies. Only one percent of this group owns no Barbies. And every girl seems to go through similar stages with her Barbies -- first, adoration, next, ambivalence, and finally, rejection. By the time they're in middle school, most girls have either thrown out their Barbies or cut off their hair and amputated multiple limbs. These aren't just casual observations -- a 2004 study observed that while young girls identify with Barbie, 10- to 14-year-olds have distanced themselves from Barbie.
But what of the recent media hype suggesting that Barbie promotes an unhealthy body image? What of careful measurements finding that a life-sized Barbie would be over seven feet tall, thinner than most anorexics, and physically unable to menstruate? In 2003, Tonner Doll Company introduced the Malibu Emme, a more realistic adult doll whose body would translate into a size 16 dress. The idea was that this doll would promote healthier body image among girls. The doll never caught on among consumers, but the question remains: would a more realistic doll be a better role model for children?
We've reported on studies about cell phones and driving before. A general consensus has formed that driving with cell phones (even hands-free phones) is dangerous. What matters most, it appears, isn't so much the physical aspect -- holding and operating the phone -- but how demanding the conversation itself is.
Research on aging has suggested that older drivers may be even more impaired by driving with a cell phone than younger drivers, since older adults tend to perform worse on "dual task" activities than younger adults. But what about the years of driving experience that older adults have? Can't they compensate for slower reaction time with more careful driving?
David Strayer and Frank Drews had older and younger adults perform the same driving simulator task. Half of them talked on a hands-free cell phone while driving, and the other half didn't. The task was to follow a pace car in the right lane of a three-lane freeway. The pace car was programmed to randomly brake at random intervals along the 24-mile simulated course. Here's a picture of the simulator they used (from the manufacturer's web site):
When human infants are born, the physical structure of their brains has not fully developed: the human brain continues to grow for more than two years after birth. It's very clear that newborn infants don't have the same cognitive abilities as babies even 6 months older. For example, they can't move their heads follow along a movement with their eyes. They appear to have very little control over their limbs. Three-month-olds have difficulty reaching and grasping objects. For humans, walking or crawling isn't a remote possibility for more than six months. Contrast this to wildebeasts, for example, which can run within 15 minutes of birth, or whales, which can swim and follow their mothers virtually as soon as they are born.
So what is it that these animals have that humans don't have? Research with primates has shown that the same region of the brain is activated when they watch another animal performing an action as when they perform the action themselves. So perhaps what babies lack is a recognition of the relationship between their own actions and the results of those actions: they lack goals.
We've reported on a variety of different studies looking video games and various measures of aggression (you can check out our "Video Games / Technology" category, and our archives) and a fairly common reaction, often coming from an avid gamer, is that this simply isn't true about him. Now one of the serious complications of doing psychological research is that our intuitions about how, or even what, we are doing can be dramatically wrong--this is why psychologists started doing experiments some one hundred and twenty odd years ago. You cannot refute a careful experiment with a personal declaratory statement, but you can turn a personal insight into a new experimental question: What aspect of personality might lead to different reactions in the face of aggressive and violent situations?
Brian Meier, Michael Robinson and Benjamin Wilkowski thought the personality factor of agreeableness might be playing a role in how individuals react to aggression-related cues. You know who agreeable people are--they are the ones who warm and friendly, and seem to be able to diffuse tense situations by bringing up helpful ideas.
Here's a picture of our daughter Nora at about 3 months of age. She looks like she's fairly aware of the events going on around her (arguably more aware than she sometimes appears now, at age 12). However, as our knowledge of how infants begin to perceive the world around them has increased, we've learned that the world of a three-month-old literally looks different to them than the world we perceive as adults. That's because vision, which seems so obvious and instinctive, is actually an active process. When we perceive the world visually, we're not just passively "seeing" what's there, we're constantly determining where one object ends and the next one begins. We're applying logical rules to help break objects into groups and understand how the two-dimensional image on the inside of our eye corresponds to a three-dimensional physical world.
In the picture of Nora, for example, how do we know that the bonnet isn't part of her body? Because it's a different color, white? But the white buckle is part of the baby carrier. Clearly the set of rules we've learned are not simple. But when do we learn them? And in what order?
One of the first questions our son Jim asks when a new movie comes out is "what's it rated?" The more "adult" the rating, the more appealing the movie is to him: PG is the lowest rating he'll even consider, PG-13 is better, and R is best. Since he's only 14, we don't take him to many R-rated movies, which is possibly what adds to their appeal.
But even PG-rated movies and TV shows still display an abundance of violence, and plenty of parents are happy to let their kids watch violent programming, especially if there isn't any sex involved. We've reported on a lot of media violence studies on Cognitive Daily, (for a summary of the effects of violent media on youth, see here, here, and here), but it still came as a surprise to us that until now, there hadn't been a brain activation study of children exposed to media violence.
A team led by John Murray has addressed that deficiency with a new experiment on 8- to 12-year-olds. They began by pre-screening 40 children by monitoring physiological responses to violent videos. They selected 15 children who showed similar responses to the videos: they were "accelerators," whose heart rate increased when viewing violence. This would allow them to more easily compare brain responses in the second phase of the study.
Twelve years ago, Greta and I were awakened by a rattling on the door of our Bronx apartment. It was about three A.M.; our children were asleep in the next room. "What should I do?" Greta whispered to me. She had woken first and was holding the deadbolt on the door locked so the intruder couldn't get in.
"Call the police," I whispered, and took hold of the lock. I ventured a peek through our peephole. I could see only the grizzled razor stubble of a man who was clearly shorter than I was. He continued to struggle with the door. He was making progress picking our lock -- I had to forcefully resist to keep the lock from turning. As I heard Greta talking with the 911 operator on the phone in the other room, I grew bolder. "Who's there?" I asked, in as gruff and aggressive a voice as I could manage. As soon as he realized there was someone in the apartment, he was gone.
About 30 seconds later, the police appeared at our door. They had been less than a block away when they received the dispatcher's call, had already searched the stairwells, and found no one. We told them our story, and they asked for a description. I told them about the man's height, and the razor stubble. "Did you notice anything else," the officer asked.
When I was a kid, school lunches didn't offer choice. I paid $1.10, and I was given four plops of foodlike substance. The entrees had names like "salisbury steak," "lasagne," or "beef stroganoff," but they all tasted about the same. Our "vegetable" was usually overcooked peas or green beans. There was a "starch," like mashed potatoes or a roll, and a dessert -- Jell-O or a cupcake -- typically the only edible item on the tray. If our lunch money wasn't stolen on the way to school, we were at least in theory presented with a balanced meal.
By the time my kids were in school, cafeteria philosophy had changed. Instead of serving up glop that no one ate, kids were given "healthy choices." They had charge accounts (no more stealing lunch money), and could select whatever they wanted to eat from a variety of options. What I don't understand is how the school nutritionists didn't realize that most kids were going to take three Jell-O's, two chocolate milks, and skip everything else. Jim regularly racked up charges of almost $10 a day. Needless to say, it didn't take long before we started resorting to homemade lunches.
I've finally found a study that addresses my concerns about putting children in charge of their own nutrition. A team led by Leonard H. Epstein gave 10- to 12-year-olds "budgets" to buy food in a laboratory setting. Then they varied the price of the foods to see if kids would modify their behavior: If we make junk food more expensive than healthy food, will kids substitute healthier foods?
My son Jim loved his bottle when he was a baby. By about 15 months of age, he loved baby formula so much that he was going through over a hundred dollars' worth a week -- more than the rest of the food budget for the entire family! (Yes, we were buying the powdered stuff, not pre-made formula.) There were weeks when we completely exhausted the local grocery store's supply.
Needless to say, soon his pediatrician pointed out he was gaining weight too quickly, and we should cut his rations down to, say, three bottles a day. It was a painful transition. Previously, all Jim would have to do was say "bottle" (which he actually pronounced "BAW-bull"), and one would be provided. Now we gave him one for breakfast, one at lunchtime, and one at bedtime -- no exceptions. Jim would put on his best adorable face, pleading "BAW-bull? BAW-bull?" and we'd say "no, Jimmy, no bottle." He'd grab one of our hands, pull us into the kitchen, and point up to the cupboard where he knew the formula was stored: "BAW-BULL!" It was heart-wrenchingly pathetic. He seemed to be thinking we simply didn't understand what he was asking for.
But figuring out what's going on inside of someone else's head is a complicated proposition, especially when one of you has limited language skills -- just as Jimmy had trouble figuring out what we were thinking, psychologists have had to resort to innovative methods to understand what babies are thinking. Probably the most common method for studying infant cognition is simply observing what babies are looking at (we've discussed severalsuchstudies), with the presumption that they look at surprising, interesting, or different stimuli longer. But perhaps such research is overreading the looking behavior. It's possible, for example, that babies simply look longer at things that are more arousing, with no deeper interest.
Much of the research on violent video games, like a vast proportion of all psychological research, has focused on college students. This shouldn't be surprising, since most college psychology departments require students to participate in experiments as a part of the Introduction to Psychology course. It's an easy way for researchers to find human participants, and a great way for students to learn how real research is done. Research results for college students often are equivalent to the population as a whole, and even when they aren't, college students can establish a baseline to compare to other groups.
But the group people are most concerned about when it comes to the effect of violent games is probably early adolescent boys, much younger than the typical college student. What if younger people respond differently to games? Unfortunately, there hasn't been much research on this age group, but Steven J. Kirsh has taken an innovate approach to predicting how the impact of violent games differs for younger adolescents. Kirsh has used more general research on aggression in adolescents to formulate several hypotheses on how violent games might fit in to those models.
Kids love robots. I have a three-year-old friend who can identify the 1950s cult icon Robbie the Robot at 20 paces. My own son Jim could do an impressive multi-voiced impression of R2D2 by age five. Now that real robots are beginning to be everyday household items (when I was a kid, if I'd known I'd be able to buy a vacuum-cleaner robot from Sears when I was a grown-up, I'd be ashamed to learn that I never actually bought one!), one wonders how real kids will respond to them.
When, for example, might a child begin to believe that a robot has a conscious mind, and that humans might communicate with robots the same way they talk with each other? The photo above (source: IRC) depicts a child interacting with Robovie, a robot designed to make human gestures, speak natural languages, and establish eye contact, just like real people. Perhaps these interactive features are the key, but perhaps a mere humanoid shape is all that is necessary to convince a child that something is "human."
A team led by Akiko Arita developed a test to see how 10-month-old infants reacted to the Robovie. They showed these babies a movie of a person talking with the robot. Some babies saw the robot responding and interacting in a natural human way, another group saw a human talking to an unresponsive robot, and a third group saw the robot interacting with an unresponsive human. Next, They were shown movies of a human talking to someone hidden behind a curtain. The curtain was removed and either a robot or a human was revealed.
Most research with infants is conducted in a similar manner: since babies can't tell us what surprises or interests them, researchers show them a stimulus of some type, then measure how long they look at the stimulus. The longer the stimulus keeps their attention, the more surprising it's surmised to be. In this case, the researchers measured how long babies looked at the newly revealed robot. Here are the results:
When babies had seen the robot interacting with the human previously, they appeared to be equally interested in a human-human conversation and a human-robot conversation later. But when the babies initially saw the human talking with an immobile robot, they looked at the hidden robot significantly longer than the hidden human. It appears that they were surprised to see another human trying to talk with it later. Perhaps more surprisingly, when the robot had tried to interact with an unresponsive human in the movie, babies again appeared to be surprised when a human tried to talk with a robot later.
So even as early as 10 months of age—well before they are able to talk themselves—it seems that infants consider interactivity to be the key factor in deciding whether a robot is something to talk to, whether it has a human mind. Perhaps it's no wonder, then, that this was my son's reaction to the scene in Star Wars when Luke and Han were awarded medals for destroying the Death Star: "Why didn't R2D2 get a medal, too?"
Arita, A., Hiraki, K., Kanda, T., & Ishiguro, H. (2005). Can we talk to robots? Ten-month-old infants expected humanoid robots to be talked to by humans. Cognition, 95, B49-B57.
Toddlers learn new words at an astonishing rate—an average, according to Steven Pinker, of over a word every two hours. Yet attempts to drill children to improve vocabulary are often frustrating. Kids seem to learn words better through observing the environment than they do by rote. So what exactly are they observing?
One possibility is that the child is paying attention to what others are looking at: if a grown-up looks at a construction site and says "look at the bulldozer," maybe kids learn "bulldozer" because they have learned to follow the grown-up's gaze. Another possibility is that kids assume that the object they don't have a word for is the one being referred to: if the child sees a tree, a bird, and a big noisy yellow thing, then when the adult says "look at the bulldozer," the child assumes "bulldozer" means "big noisy yellow thing" because she already knows that a tree is a tall green thing and a bird is a fluffy flying thing that eats worms.
One of the symptoms of autism is that people with autism don't perceive the intentions of others—so if we learn language only by observing the gaze of others, it would seem that kids with autism would have more difficulty learning language. Mellissa Allen Preissler and Susan Carey developed an experiment to see if toddlers with autism could use the speaker's gaze to learn the names of objects. They gave 24-month-olds (some with autism, some normal) objects they'd never seen before (a doorstop, soap dish, tire gauge, or cheese grater). The experimenter held a different new object, and gazed at that object while the toddler was playing with his or her object. Then the experimenter named the object in her hand with a nonsense word ("peri"). She placed her object and the toddler's object in a bag with two other objects. Then she asked the toddler to "find the peri." Children with autism most frequently chose the object they themselves had been holding, but normal children correctly identified the object the experimenter had been looking at 70 percent of the time.
In a second experiment, kids were presented with two objects—one familiar, and one unfamiliar (as reported by the children's parents). The experimenter asked kids to "show me a blicket," using a nonsense word to refer to the unfamiliar object. In this case, both normal children and children with autism were able to successfully identify the novel object. Here's a summary of the results of both experiments:
So though children with autism are often unable to follow the gaze of a speaker to learn what object he is referring to, they are just as able as normal children to use the process of elimination to associate a word with a new object. Though social cues such as observing the gaze of another are important in learning language, the same concepts can be learned other ways. Perhaps what's most amazing about kids' ability to learn language is how effortless it seems, even for kids with impairments at making inferences about others' intentions.
Preissler, M.A., & Carey, S. (2005). The role of inferences about referential intent in word learning: Evidence from autism. Cognition, 97, B13-B23.
IQ has been the subject of hundreds, if not thousands of research studies. Scholars have studied the link between IQ and race, gender, socioeconomic status, even music. Discussions about the relationship between IQ and race and the heritability of IQ (perhaps most notably Steven Jay Gould's Mismeasure of Man) often rise to a fever pitch. Yet for all the interest in the study of IQ, there has been comparatively little research on other influences on performance in school.
Angela Duckworth and Martin Seligman estimate that for every ten articles on intelligence and academic achievement, there has been fewer than one about self-discipline. Even so, the small body of research on self-discipline suggests that it has a significant impact on achievement. Walter Mischel and colleagues found in the 1980s that 4-year-olds' ability to delay gratification (for example, to wait a few minutes for two cookies instead of taking one cookie right away) was predictive of academic achievement a decade later. Others have found links between personality and college grades, and self-discipline and Phi Beta Kappa awards. Still, most research on self-discipline has achieved inconsistent results, possibly due to the difficulty of measuring self-discipline. Could a more robust measure of self-discipline demonstrate that it's more relevant to academic performance than IQ?
To address this question, Duckworth and Seligman conducted a two-year study of eighth graders, combining several measures of self-discipline for a more reliable measure, and also assessing IQ, achievement test scores, grades, and several other measures of academic performance. Using this better measure of self-discipline, they found that self-discipline was a significantly better predictor of academic performance 7 months later than IQ.
How did they arrive at this result? They studied a group of 8th-graders at the beginning of the school year. They used five different measures of self-discipline: the Eysenck Junior Impulsiveness scale (a 23-question survey about impulsive behavior), the Brief Self-Control Scale (13 questions measuring thoughts, emotions, impulses, and performance), two questionnaires in which parents and teachers rated the student's self-discipline, and a version of Mischel's delay of gratification task. Students were given an envelope containing $1, and were told they could spend it immediately or bring it back in a week for a $2 reward. The students were also given an IQ test (OLSAT7, level G).
At the end of the school year, students were surveyed again and several measures of academic performance were taken. The data included final GPA (grade point average), a spring achievement test, whether they had been admitted to the high school of their choice, and number of hours they spent on homework. All except two measures correlated more strongly to self-discipline than to IQ. Scores on spring achievement tests were correlated both to self-discipline and IQ, but there wasn't a significant difference. Duckworth and Seligman suggest that this could be partially due to the fact that achievement tests are similar in format to IQ tests. The other area where there was no significant difference was in school absenses.
Most impressive was the whopping .67 correlation between self-discipline and final GPA, compared to a .32 correlation for IQ. This graph dramatically shows the difference between the two measures:
Both IQ and self-discipline are correlated with GPA, but self-discipline is a much more important contributor: those with low self-discipline have substantially lower grades than those with low IQs, and high-discipline students have much better grades than high-IQ students. Even after adjusting for the student's grades during the first marking period of the year, students with higher self-discipline still had higher grades at the end of the year. The same could not be said for IQ. Further, the study found no correlation between IQ and self-discipline—these two traits varied independently.
This is not to say this study will end the debate on IQ and heredity. The study says nothing about whether self-discipline is heritable. Further, the self-discipline might be correlated differently with achievement for different populations; this study covered only eighth graders in a relatively privileged school. Perhaps self-discipline has a different role at other ages, or in more diverse populations (though the study group was quite ethnically diverse—52% White, 31% Black, 12% Asian, and 4% Latino). Perhaps the most important question which remains is how best to teach children self-discipline—or whether it can be taught at all.
Duckworth, A.L., & Seligman, M.E.P. (2005). Self-discipline outdoes IQ in predicting academic performance of adolescents. Psychological Science, 16(12), 939-944.
Eric Durbrow pointed me to this article in the Globe and Mail. Its lead sentence offers a surprising claim:
Parents take note: Reading to your preschoolers before bedtime doesn't mean they are likely to learn much about letters, or even how to read words.
But aren't teachers and literacy advocates constantly urging parents to read to their kids? Aren't their entreaties backed by research?
The Globe and Mail article reports on research published in Psychological Science by Mary Ann Evans and Jean Saint-Aubin. I decided to look at the original article to see if it lives up to the dramatic claim offered in the mainstream media report.
Evans and Saint-Aubin note in the introduction to their experiments that little research has been done specifically focusing on the relationship between shared book reading and orthographic development. In other words, while there have been studies about parents reading to their kids, these studies don't specifically examine how kids learn about the shape of letters and how letters form words. So there may be some cause for concern.
The Globe and Mail article does offer a good summary of Evans and Saint-Aubin's work. They tracked the eye movements of 4-year-olds as their parents read picture books to them from a computer screen. Despite using several different types of books, including books where the text was enclosed in conversation bubbles superimposed on the illustrations comic-book style, the children rarely looked at the words on the page. They generally looked at the pictures more than 20 times as often as they looked at the words. Evans and Saint-Aubin quite reasonably ask how these children could possibly be learning anything about words or reading.
The Globe and Mail article quotes Evans as saying that parents believe that reading to their kids will help them learn to read. "That's true to an extent in that reading to your children will help them develop an understanding of storyline. But it's not necessarily helping them to learn how to decode the words on the page."
Does the research really suggest that reading to children only helps kids understand "storyline"? In their second experiment, Evans and Saint-Aubin had teachers read two different versions of the same story to a new group of children, again monitoring eye movements. In the modified story, the text was changed to refer to specific details in the pictures. On pages with references to specific picture details, children looked at the corresponding area of the picture nearly the entire time the page was being read. This suggests that the kids are paying close attention to the meaning of the text in the story. Wouldn't that at least help children develop vocabulary skills?
Indeed it would, and Evans and Saint-Aubin cite two meta-analyses and three studies showing that reading to children correlates with vocabulary knowledge. While vocabulary may be important for parents, for psychologists, language ability is a separate skill from reading ability. However, while the five articles that Evans and Saint-Aubin cite find that there is a stronger impact on vocabulary than on reading achievement, each study does show some association between shared reading to preschoolers and school-aged reading ability.
Evans and Saint-Aubin argue that this small effect may be due to the fact that parents who read to their children are also more likely to specifically coach their children in orthographic skills. Perhaps this is true—perhaps it is the coaching, and not the shared reading, which leads to improved reading ability in school-aged kids.
But is the Globe and Mail article's lead sentence warranted—does reading to children really lead to no improvement in reading ability? From a psychology research perspective, it's arguable that it does not. But for parents trying to help their children develop the skills that will help them in the future, the question may be irrelevant. Developing vocabulary skills and a love of books are important in their own right. In the long run, these skills may lead to better readers: Evans and Saint-Aubin's report doesn't address long-term development.
Finally, I would argue that children whose parents read to them to are substantially more likely to learn to read—because if no reading occurs, then there is much less opportunity for coaching. As Evans points out in her interview with the Globe and Mail, one of the simplest ways to coach children on reading skills is to point to the words while we read them.
Evans, M.A., & Saint-Aubin, J. (2005) What children are looking at during shared storybook reading: Evidence from eye movement monitoring. Psychological Science, 16(11), 913-920.
One of the most difficult things to demonstrate scientifically is cause and effect. Often a study will show that two items—say, smoking and lung cancer—are associated with one another. But it's another thing entirely to suggest that smoking causes lung cancer in humans. Only after hundreds of studies have been conducted do we now accept that hypothesis as fact.
Now consider a small child, trying to make sense of her world. She might want to know what makes the lights come on in her room. She notices that the lights tend to come on whenever a grown-up walks in. But sometimes, in the middle of the night, a grown-up walks in the room and the light does not come one. Perhaps something else is the cause.
So how do children assign cause and effect to everyday actions? Maybe they believe they themselves have control—by crying, they can summon an adult to the room, and this will cause the lights to come on. Or maybe they assess the probability of an action occurring—since an adult coming into the room is usually associated with lights, it must be the cause.
Tamar Kushnir and Alison Gopnik designed an experiment to try to separate these two mechanisms for determining causality. They showed 4-year-olds a box that appeared to play music when a wooden toy building block is placed upon it. In fact, the box was controlled by the experimenter; this allowed them look at the child's reaction to different interactions between the building blocks and the musical box.
In every trial, one of two different blocks (Block A and Block B) was placed on the box three times—for a total of six (two blocks, three times each). In a given trial, Block A might result in the box playing music three times, while Block B might result in the box playing music only once. Then the child was asked which block should be placed on the box to "make it go" again. In cases like this, 68 percent of the time (significantly better than chance) the child selected Block A.
But what if Block A only caused the box to play music twice out of the three times? If Block B works just one out of three times, then Block A should still be the better bet, right? Kushnir and Gopnik found that in this case, it depended on how the process was presented. For example, consider the following scenario:
Block A
Block A
Block B
Block B
Block A
Block B
music
music
no music
no music
no music
music
In this case, only 63 percent of kids selected Block A—not significantly better than chance. But a change in the procedure caused even more dramatic results. If the experimenter let the child place the blocks on the box for the last two tries, then despite the fact that Block A had corresponded to music twice and Block B had only once, the kids chose Block B a whopping 79 percent of the time: they themselves had placed Block B on the box and seen the music play. They were weighing the effects of their own actions more strongly than the probability of a particular block corresponding to music.
The sequence in which the blocks corresponded to music mattered, too. Consider this variation:
Block A
Block A
Block B
Block B
Block A
Block B
music
no music
music
no music
music
no music
In this case, no matter whether experimenter placed all the blocks on the box herself or the child took over for the last two tries, the child picked Block A nearly all the time (95 percent when the child took over, and 84 percent when the experimenter handled all the blocks).
It appears that even these young children can respond both to probability and to the results of their own actions, using them to make predictions about cause. When probability and the results of their own actions conflict, the child will weigh his or her actions more strongly than the probabilistic choice. So from a very young age, children seem to believe that they have an important influence on events. Only when they see clearly that their own influence is minimal do they take into account other possibilities—even though they are well equipped to do so.
Kushmir, T., & Gopnik, A. (2005). Young children infer causal strength from probabilities and interventions. Psychological Science, 16(9), 678-683.
This weekend, robot cars competed in a challenge that most humans would find trivial: drive 132 miles in 12 hours without crashing. Yet crash, they do. The difficult part isn't so much the steering and acceleration, it's determining the difference between an obstacle you must navigate around and a benign shadow on the road; it's deciding whether that dark patch ahead is open roadway or deep water. These things are so easy for humans that we take them for granted, yet for a machine it's a task literally in its infancy.
By the time a child is 2, it can easily tell the difference between a shadow and a real object, walk through an environment crowded with obstacles, do all the things that robots find most difficult. So how do babies learn these critical perceptual tasks that are so hard for computers? A team led by Paul Quinn investigated one aspect of this problem—how babies group similar objects.
Grouping objects is one way we are easily able to navigate through an environment: why, for example, do we see hundreds of leaves on a tree and recognize they are part of a solid object, but at the same time understand that the dapples of sunlight they filter onto the ground are not? One reason is that the leaves are all similar in shape, but the light admitted through the spaces between the leaves is not. You've probably heard the term "Gestalt," which refers to the set of principles we use to make visual sense of the world. The principles are simple: similarly shaped objects should be grouped together, items moving together are probably part of the same object, things closer together are likely to be connected. Somehow, however, while humans and animals are great at putting these rules together in order to function successfully, the challenge of programming a computer to do the same thing is a daunting task.
What Quinn's team wanted to study is whether babies are born with all of the Gestalt rules intact, or whether some of them are learned or acquired as they grow. A different team led by Quinn had established that babies as young as three months old are able to group objects that are similar in brightness or darkness. Now they wanted to examine whether babies can also group objects based on shape.
So how do you test such a thing in a baby too young to speak? Quinn et al. used a familiarization procedure: you show a baby one item until she's bored with it. Then show her a two new items—one is the same, and one is different—and see how which one seems to hold her interest more. In their first experiment, they used arrays of Xs and Os:
The researchers reasoned that if babies could successfully group the shapes, they would be more interested in a different pattern of blocks than a similar one. Two groups of babies were tested: 3- to 4-month-olds, and 6- to 7-month-olds. The younger babies stared at both patterns of blocks for an equal amount of time. Older babies, however, looked at the different pattern (horizontal blocks after being familiarized to vertical rows, or vertical blocks after horizontal rows) significantly more of the time—57.58 percent, compared to 42.42 percent for the similar pattern.
But what if babies weren't actually grouping the objects, but rather simply observing that the overall pattern had rotated? To address this concern, the team conducted a new experiment. In the first part, the procedure was the same, except that now babies were tested on patterns of Xs and Os instead of blocks:
But for the second part, babies were shown random patterns of Xs and Os:
The 3- to 4-month-olds again did not prefer either pattern, whether organized in rows or columns, or random. However, the 6- to 7-month-olds, as in the first experiment, preferred the rotated pattern of columns and rows (59.76 percent to 40.24 percent), but were ambivalent about the rotated random patterns, suggesting that the difference between the babies is really a difference in grouping ability.
But perhaps the problem wasn't that 3- to 4-month-olds couldn't group by shape, but that they couldn't distinguish between Xs and Os. So they gave one final test:
Now both younger babies (62.95 to 37.05 percent) and older babies (66.50 to 33.50 percent) preferred the solid pattern to the identical pattern. Clearly, both groups of babies can tell the difference between an X and an O, so the evidence really does seem to indicate that older babies have learned to group by shape.
When the Gestalt principles were being uncovered in the 1920s, researchers argued that the rules were innate. But Quinn and his colleagues argue that their experiment shows that babies actually learn how to group objects based on shape sometime between 3 and 6 months of age—so it's not an innate ability. With dozens of other principles to learn, and with an even more complex array of rules governing how the principles are applied, it's astounding to realize that babies acquire them so quickly, while scientists struggle to duplicate the same tasks.
Eventually robots will be able to drive trucks through the desert, but it will have taken much more than two years to accomplish—and hundreds of other human problems, such as understanding language, creating art, and feeling true love, will remain unsolved.
Quinn, P.C., Bhatt, R.S., Brush, D., Grimes, A., & Sharpnack, H. (2002). Development of form similarity as a Gestalt grouping principle in infancy. Psychological Science, 13(4), 320-328.
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The average 3- to 10-year-old girl in the U.S. owns eight Barbies. Only one percent of this group owns no Barbies. And every girl seems to go through similar stages with her Barbies -- first, adoration, next, ambivalence, and finally, rejection. By the time they're in middle school, most girls have either thrown out their Barbies or cut off their hair and amputated multiple limbs. These aren't just casual observations -- a 2004 study observed that while young girls identify with Barbie, 10- to 14-year-olds have distanced themselves from Barbie.
But what of the recent media hype suggesting that Barbie promotes an unhealthy body image? What of careful measurements finding that a life-sized Barbie would be over seven feet tall, thinner than most anorexics, and physically unable to menstruate? In 2003, Tonner Doll Company introduced the Malibu Emme, a more realistic adult doll whose body would translate into a size 16 dress. The idea was that this doll would promote healthier body image among girls. The doll never caught on among consumers, but the question remains: would a more realistic doll be a better role model for children?
Here's a picture of our daughter Nora at about 3 months of age. She looks like she's fairly aware of the events going on around her (arguably more aware than she sometimes appears now, at age 12). However, as our knowledge of how infants begin to perceive the world around them has increased, we've learned that the world of a three-month-old literally looks different to them than the world we perceive as adults. That's because vision, which seems so obvious and instinctive, is actually an active process. When we perceive the world visually, we're not just passively "seeing" what's there, we're constantly determining where one object ends and the next one begins. We're applying logical rules to help break objects into groups and understand how the two-dimensional image on the inside of our eye corresponds to a three-dimensional physical world.
One of the first questions our son Jim asks when a new movie comes out is "what's it rated?" The more "adult" the rating, the more appealing the movie is to him: PG is the lowest rating he'll even consider, PG-13 is better, and R is best. Since he's only 14, we don't take him to many R-rated movies, which is possibly what adds to their appeal.
