2012 May 17 Thursday
Larger Role Found For Genes In Personality

You are free to become the kind of person your genes want you to be.

Genes play a greater role in forming character traits - such as self-control, decision making or sociability - than was previously thought, new research suggests.

A study of more than 800 sets of twins found that genetics were more influential in shaping key traits than a person's home environment and surroundings.

Psychologists at the University of Edinburgh who carried out the study, say that genetically influenced characteristics could well be the key to how successful a person is in life.

The study of twins in the US – most aged 50 and over– used a series of questions to test how they perceived themselves and others. Questions included "Are you influenced by people with strong opinions?" and "Are you disappointed about your achievements in life?"

The results were then measured according to the Ryff Psychological Well-Being Scale which assesses and standardises these characteristics.

By tracking their answers, the research team found that identical twins - whose DNA is exactly the same - were twice as likely to share traits compared with non-identical twins.

My recurring thought in genetic control of personality: Once it becomes possible for prospective parents to choose brain gene variations for their offspring what sorts of minds will they choose to make? The answer to that question will some day start to determine the future of the human race. My guess is that offspring genetic engineering will become very popular within 20 years at most.

Finally genetic testing costs have fallen far enough to chase after the genetic variants that influence cognitive traits. What makes this chase hard: each genetic variant that influences cognitive traits has only a very small effect. Our brain-altering genetic variants are large in number and each has only small impact.

ITHACA, N.Y. – Genetic factors explain some of the variation in a wide range of people's political attitudes and economic decisions – such as preferences toward environmental policy and financial risk taking – but most associations with specific genetic variants are likely to be very small, according to a new study led by Cornell University economics professor Daniel Benjamin.

The research team arrived at the conclusion after studying a sample of about 3,000 subjects with comprehensive genetic data and information on economic and political preferences. The researchers report their findings in "The Genetic Architecture of Economic and Political Preferences," published by the Proceedings of the National Academy of Sciences Online Early Edition, May 7, 2012.

The study showed that unrelated people who happen to be more similar genetically also have more similar attitudes and preferences. This finding suggests that genetic data - taken as a whole – could eventually be moderately predictive of economic and political preferences. The study also found evidence that the effects of individual genetic variants are tiny, and these variants are scattered across the genome. Given what is currently known, the molecular genetic data has essentially no predictive power for the 10 traits studied, which included preferences toward environmental policy, foreign affairs, financial risk and economic fairness.

This conclusion is at odds with dozens of previous papers that have reported large genetic associations with such traits, but the present study included ten times more participants than the previous studies.

"An implication of our findings is that most published associations with political and economic outcomes are probably false positives. These studies are implicitly based on the incorrect assumption that there are common genetic variants with large effects," said Benjamin. "If you want to find genetic variants that account for some of the differences between people in their economic and political behavior, you need samples an order of magnitude larger than those presently used," he added.

I'm looking forward to the day when I can identify thru genetic testing all the people who are lucky enough to share with me the cognitive traits that enable us to share the same profound understanding of why everyone is wrong when they disagree with us.

By Randall Parker    2012 May 17 10:31 PM   Entry Permalink | Comments (6)
2012 May 02 Wednesday
Dopamine Distribution Causes Slackers And Go-Getters?

Dopamine is a neurotransmitter and genetic variants for it influence behavior in a number of ways. If you are a slacker you probably have a lot of dopamine activity in your insula. If you are motivated and work really hard you probably have a lot activity in your striatum and ventromedial prefrontal cortex. Blame your dopamine if you can't make yourself work hard enough.

Whether someone is a "go-getter" or a "slacker" may depend on individual differences in the brain chemical dopamine, according to new research in the May 2 issue of The Journal of Neuroscience. The findings suggest that dopamine affects cost-benefit analyses.

The study found that people who chose to put in more effort — even in the face of long odds — showed greater dopamine response in the striatum and ventromedial prefrontal cortex, areas of the brain important in reward and motivation. In contrast, those who were least likely to expend effort showed increased dopamine response in the insula, a brain region involved in perception, social behavior, and self-awareness.

Researchers led by Michael Treadway, a graduate student working with David Zald, PhD, at Vanderbilt University, asked participants to rapidly press a button in order to earn varying amounts of money. Participants got to decide how hard they were willing to work depending on the odds of a payout and the amount of money they could win. Some accepted harder challenges for more money even against long odds, whereas less motivated subjects would forgo an attempt if it cost them too much effort.

My guess is there's genetic differences play a large role in differences in brain dopamine activity. Once it becomes possible to choose offspring genetic variants will people opt make babies who will be more motivated than their parents? My guess is yes, genetically engineered future generations of humans will be more motivated by design.

Brain PET scans were used to determine individual responsiveness to dopamine.

In a separate session, the participants underwent a type of brain imaging called positron emission tomography (PET) that measured dopamine system activity in different parts of the brain. The researchers then examined whether there was a relationship between each individual's dopamine responsiveness and their scores on the motivational test described earlier.

Imagine a country where employers are allowed to require a PET scan as a condition of employment. If PET scan costs were cheap enough some employers would use them.

By Randall Parker    2012 May 02 09:11 PM   Entry Permalink | Comments (8)
2011 December 06 Tuesday
Better Looking Politicians Get More TV Time

News show managers realize that humans want to look at more attractive people. So news programs show better looking Congressional representatives more often than less attractive ones.

The better the looks of United States Congresspersons, the more television coverage they receive, shows a new study from the University of Haifa recently published in the journal Political Communication. The reason behind this? Television journalists think their viewers prefer to see physically attractive people. “Physical appearance ranked third in the criteria for gaining television coverage, and ranked higher than seniority, position in Congress and legislative activity in this respect,” noted the authors of the study.

One of the parties could gain a competitive advantage if it more systematically ranked potential candidates by their looks. A party that recruited more aggressively by physical appeal would pick up a lot of votes not only of the poorly informed but also of the well informed. People do not realize the extent to which their brain responds to subconsciously detected patterns in stimuli.

Imagine taking a large number of early primary contestants and getting them rated using students in another country. For a pretty low cost funders of candidates could learn where to better direct their money to have higher success rates.

The study, conducted by University of Haifa researchers, Dr. Israel Waismel-Manor of the School of Political Science and Prof. Yariv Tsfati of the Department of Communication, asked 463 Israeli students to rank the physical attractiveness of Members of the 110th United States Congress (2007) based on the official photographs posted on Congress’s website. The authors chose that year for its distance from elections, which could otherwise influence media coverage. Israeli students were chosen for this, so as to eliminate the possibility of biases stemming from political views or previous knowledge of Congresspersons, both of which could influence an objective judgment of physical attractiveness. So as to determine that the Israeli assessment of ‘good looks’ is not culturally different from the American judgment, the researchers compared the Israeli ranking to a ranking given by 30 American students, to find a very high correlation between the two.

People also prefer to be led by lower pitched voices.

HAMILTON -- Voters prefer to choose candidates with lower-pitched voices, according to new findings by researchers at McMaster University.

A team from the Department of Psychology, Neuroscience and Behavior found that study subjects were more inclined to vote for men with lower-pitched voices, suggesting that perceptions developed long ago may be still be influencing the way we choose leaders.

"We're looking at men's low voice-pitch as a cue to dominance, which is related to leadership," says graduate student Cara Tigue, lead author of the paper, published on-line today in the journal Evolution and Human Behavior. "Throughout our evolutionary history, it would have been important for our ancestors to pay attention to cues to good leadership, because group leaders affected a person's ability to survive and reproduce within a group. We're looking at it in a present-day, 21st-century context."

To test voice-related perceptions, the researchers manipulated archival recordings of US presidents, creating lower- and higher-pitched versions of each voice.

They played the altered recordings for test subjects and asked them to rate their perceptions of the speakers' attractiveness, leadership potential, honesty, intelligence and dominance. They also asked subjects which version of the voice they would prefer to vote for, both in peacetime and wartime.

Though the motivations were different, in all cases they preferred candidates with lower-pitched voices.

When offspring genetic engineering becomes possible don't be surprised if some prospective parents decide to give their kids deeper voices.

I also expect voice reengineering by plastic surgeons will some day become technically feasible and popular. Go for that deeper voice to get promotions up management ranks. It will be money well spent.

By Randall Parker    2011 December 06 10:29 PM   Entry Permalink | Comments (5)
2011 October 10 Monday
More Easily Embarrassed More Trusted

Beware of people who only feign embarrassment.

BERKELEY — If tripping in public or mistaking an overweight woman for a mother-to-be leaves you red-faced, don’t feel bad. A new study from the University of California, Berkeley, suggests that people who are easily embarrassed are also more trustworthy, and more generous.

In short, embarrassment can be a good thing.

This makes sense: People with a greater fear of embarrassment will refrain from doing things that less easily embarrassed people won't hesitate to do. The fear of embarrassment can be counted on to constrain some forms of anti-social behavior. So a person more prone to embarrassment engages in fewer acts that would make others morally outraged.

The more easily embarrassed both behaved more altruistically and were perceived as more trustworthy.

The college students also participated in the “Dictator Game,” which is used in economics research to measure altruism. For example, each was given 10 raffle tickets and asked to keep a share of the tickets and give the remainder to a partner. Results showed that those who showed greater levels of embarrassment tended to give away more of their raffle tickets, indicating greater generosity.

Researchers also surveyed 38 Americans whom they recruited through Craigslist. Survey participants were asked how often they feel embarrassed. They were also gauged for their general cooperativeness and generosity through such exercises as the aforementioned dictator game.

In another experiment, participants watched a trained actor being told he received a perfect score on a test. The actor responded with either embarrassment or pride. They then played games with the actor that measured their trust in him based on whether he had shown pride or embarrassment.

Time and again, the results showed that embarrassment signals people’s tendency to be pro-social, Feinberg said. “You want to affiliate with them more,” he said, “you feel comfortable trusting them.”

What I want to know: When it becomes possible to genetically engineer offspring for greater or lesser tendency toward embarrassment will parents choose to make their kids more or less easily embarrassed than they are? The answer to that question will probably determine the level of trust in future human societies and the level of corruption as well.

What I also want to know: How highly correlated are shyness and the tendency toward embarrassment?

By Randall Parker    2011 October 10 05:53 AM   Entry Permalink | Comments (6)
2011 September 19 Monday
Yawning For Brain Temperature Regulation?

People yawn less when the outdoor temperature exceeds body temperature.

A study led by Andrew Gallup, a postdoctoral research associate in Princeton University's Department of Ecology and Evolutionary Biology, is the first involving humans to show that yawning frequency varies with the season and that people are less likely to yawn when the heat outdoors exceeds body temperature. Gallup and his co-author Omar Eldakar, a postdoctoral fellow in the University of Arizona's Center for Insect Science, report this month in the journal Frontiers in Evolutionary Neuroscience that this seasonal disparity indicates that yawning could serve as a method for regulating brain temperature.

Years ago I read the speculation that yawning's purpose was to show one's teeth to scare away predators. That didn't seem plausible. This theory seems more plausible. Though why would yawning happen more when tired?

The body can't do yawn air heat exchange to cool the brain if the air temperature is too high.

Gallup and Eldakar documented the yawning frequency of 160 people in the winter and summer in Tucson, Ariz., with 80 people for each season. They found that participants were more likely to yawn in the winter, as opposed to the summer when ambient temperatures were equal to or exceeding body temperature. The researchers concluded that warmer temperatures provide no relief for overheated brains, which, according to the thermoregulatory theory of yawning, stay cool via a heat exchange with the air drawn in during a yawn.

Does the brain get hotter when it is fatigued? I am currently reading Roy Baumeister and John Tierney's excellent book Willpower and wonder whether conditions that deplete willpower also heat up the brain.

By Randall Parker    2011 September 19 10:46 PM   Entry Permalink | Comments (12)
2011 September 13 Tuesday
Recently Sick React More To Sick Faces

People who have recently been ill react most strongly to disfigured faces.

Now a study in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science, offers intriguing new evidence of the connection moving in the other direction: from physiological to psychological immune reactions. "When people have been recently sick, and therefore recently activated their physiological immune systems, they are more likely to pay attention to and display avoidance of disfigured faces"—which they read, like a rash or a sneeze, as a sign of contagion, says University of Kentucky psychologist Saul Miller. Miller conducted the study with Jon K. Maner of Florida State University.

I am fascinated by the myriad factors below our conscious awareness which alter how the mind functions. If this result is correct then a recent bout of sickness will cause a mind to look more intently at faces that show signs of disease. So how else does, say, a cold or flu or bacterial infection alter how we perceive the world around us even once the immune system has beaten back the invading pathogens?

To put it another way: Just how many ways does human DNA program the development of the mind to alter cognition in response to illness, diet, and sensory inputs?

Two experiments showed that the recently ill more vigilantly pay attention to and avoid others who might make them sick. In the first, faces, some disfigured and some normal, were displayed on a screen. When they disappeared, either a circle or square appeared, and the person had to press a key, as quickly as possible, indicating which shape they saw. When the face appeared in a different portion of the screen, the participant had to shift her attention to it. A longer lag in switching meant more attention was paid to the face. After 80 trials, participants answered a questionnaire about whether they had been ill—"feeling a little under the weather," "had a cold or flu recently," for instance—and if so, when, from today to a year or more ago. Other questions measured feelings of vulnerability to disease and germs. The results: Independent of their conscious worries, those who had more recently been ill paid more attention to the disfigured faces than to the normal faces. Those who hadn't been ill showed no difference in reaction time.

In the second experiment participants had to push a joystick—a tested indication of avoidance—in response to a disfigured face and pull (showing approach) for normal face. Everyone was quicker to push away the disfigured one or pull the normal one. But those who'd been sick were even quicker than normal in avoiding the "sick" face, and the sicker they'd been, the faster they pushed. The not-ill people showed no difference.

A much larger scale study that compared people who had similar levels of illness might turn up super responders (react most severely to sick-looking faces) and very weak responders. Such a study could be used to look for genetic variants that influence our subconscious response to sick people.

By Randall Parker    2011 September 13 10:28 PM   Entry Permalink | Comments (1)
2011 May 24 Tuesday
Genetic Basis For Prudent Spending Habits

Frugality is (at least partially) in your genes.

In a study of identical twins, which was published in the April edition of Journal of Consumer Research, marketing professors Itamar Simonson of Stanford University and Aner Sela of the University of Florida report that individual consumer preferences — for such products as chocolate, hybrid cars, movies and jazz — are genetically linked. Those preferences, the authors suggest, are a reflection of individual “prudence” — an inheritable predisposition to living “in the mainstream” or “on the edge” or somewhere in between.

This sort of research tends to undermine the credibility of movements that call for a turning away from materialism, restraint in lifestyles for ecological protection, and other movements that argue that we must consume less. The people who are big spenders lack the innate qualities that would enable voluntary reductions in spending. Also, calls for greater savings for retirement are only going to be heard by the genetically more prudent.

The prudent and spendthrift make unsuccessful marriages. Not surprising given that the spending of one spouse is causing emotional pain in the more prudent spouse who fears the consequences of having little money.

What I want to know: Once it becomes possible to choose offspring genetic endowments will the average person choose genes for their offspring that make their offspring more or less frugal than their parents? In other words, will the human population become more or less frugal than it is now?

What I also wonder: Will the power to choose offspring genes lead to the disappearance of the middle ground? For example, will the prudent-leaning make their kids even more frugal while the spendthrifts make their kids even more oblivious to risks and long term consequences of spending decisions?

By Randall Parker    2011 May 24 07:35 PM   Entry Permalink | Comments (15)
2011 April 22 Friday
Brain Region Determines Embarrassment Level

If you could suppress your brain's "pregenual anterior cingulate cortex" you could probably avoid the feeling of embarrassment.

The twist to the experiment was that most of the subjects had neurodegenerative diseases, which helped scientists identify a thumb-sized bit of tissue in the right hemisphere of the front part of the brain called the "pregenual anterior cingulate cortex" as integral to embarrassment.

The degree to which the singers were embarrassed in hearing themselves sing "My Girl" – the 1964 hit by the Temptations – depended on the integrity of this particular region.

"In healthy people, watching themselves sing elicits a considerable embarrassment reaction," said Virginia Sturm, a postdoctoral fellow at UCSF. Their blood pressure goes up, their heart rate increases, and their breathing changes, she explained. People who had neurological damage in the medial frontal cortex, however, responded more indifferently.

Too embarrassed to learn singing or to approach someone you have a crush on? It'd be mighty handy to be able to push a button on your iPhone and turn turn your pregenual anterior cingulate cortex. Maybe in 20 or 30 years you'll be able to get injected by nanobots that travel to that part of the brain and then start listening for orders to suppress neural activity.

Then there's offspring genetic engineering. When it becomes possible to choose genetic variants that control the size of the pregenual anterior cingulate cortex will you want to make your kids have a smaller one or a bigger one you have?

"This brain region predicted the behavior," said Sturm. "The smaller the region, the less embarrassed the people were."

The feeling of embarrassment is a restraint on behavior. Imagine that anyone who wants a job on Wall Street was required to have a pregenual anterior cingulate cortex with some minimum size to assure they can feel embarrassed. Would they be less likely to do corrupt things? Ditto elected officials. Require a bigger pregenual anterior cingulate cortex at each step up in elected level?

By Randall Parker    2011 April 22 09:30 AM   Entry Permalink | Comments (2)
2011 January 24 Monday
3 Year Olds Out Of Control Set Pattern For Life

Not exactly a Blank Slate view of human nature...

DURHAM, N.C. -- A long-term study has found that children who scored lower on measures of self-control as young as age 3 were more likely to have health problems, substance dependence, financial troubles and a criminal record by the time they reached age 32.

Self-control in the more than 1,000 New Zealand children who participated in the study was assessed by teachers, parents, observers and the children themselves. It included measures like "low frustration tolerance, lacks persistence in reaching goals, difficulty sticking with a task, over-active, acts before thinking, has difficulty waiting turn, restless, not conscientious."

Fast-forward to adulthood, and the kids scoring lowest on those measures scored highest for things like breathing problems, gum disease, sexually transmitted disease, inflammation, overweight, and high cholesterol and blood pressure, according to an international research team led by Duke University psychologists Terrie Moffitt and Avshalom Caspi.

With the crashing costs of DNA sequencing we are going to find out soon how much genetic variations contribute to creating toddlers who are no good. I hear George Thorogood singing.

On the day I was born, the nurses all gathered 'round
And they gazed in wide wonder, at the joy they had found
The head nurse spoke up, and she said leave this one alone
She could tell right away, that I was bad to the bone

Yes that head nurse was on to something.

The impulsivity and relative inability to think about the long-term of the lower self-control individuals gave them more difficulty with finances, like savings, home ownership and credit card debt. They also were more likely to be single parents, have a criminal conviction record, and be dependent on alcohol, tobacco, cannabis and harder drugs.

"These adult outcomes were predictable across the entire spectrum of self-control scores, from low to high," Moffitt said.

Toddlers bent on a life of crime.

(Reuters Life!) - Children who have low levels of self-control at three are more likely to have health and money problems and a criminal record by the age of 32, regardless of background and IQ, scientists said on Monday.

Science is gradually rediscovering ancient wisdom about human nature.

By Randall Parker    2011 January 24 11:57 PM   Entry Permalink | Comments (34)
2010 November 08 Monday
Seeing Meat Makes Men Less Aggressive?

Be careful around vegetarians. They rarely get the calming benefit of looking at meat. A researcher found that the sight of meat made men less aggressive.

Frank Kachanoff was surprised. He thought the sight of meat on the table would make people more aggressive, not less. After all, don’t football coaches feed their players big hunks of red meat before a game in hopes of pumping them up? And what about our images of a grunting or growling animal snarling at anyone who dares take their meat away from them? Wouldn’t that go for humans, too?

Kachanoff, a researcher with a special interest in evolution at McGill University’s Department of Psychology, has discovered quite the reverse. According to research presented at a recent symposium at McGill, seeing meat appears to make human beings significantly less aggressive. “I was inspired by research on priming and aggression, that has shown that just looking at an object which is learned to be associated with aggression, such as a gun, can make someone more likely to behave aggressively. I wanted to know if we might respond aggressively to certain stimuli in our environment not because of learned associations, but because of an innate predisposition. I wanted to know if just looking at the meat would suffice to provoke an aggressive behavior.”

This makes sense in a way: Hunters had to be aggressive during the hunt. But once the deer, antelope, moose, or buffalo was brought down and cut open there was no more need for the aggression needed during the hunt.

Does this also speak against hamburgers? Does hiding meat under the bun deprive us of the relaxation that meat should bring us? Should we prefer rare steaks? I am guessing that redder meat works better to calm down wild guys.

Update: If meat makes men less aggressive then does our modern environment (where men rarely hunt) leave us visually deficient to meat exposure?

By Randall Parker    2010 November 08 10:18 PM   Entry Permalink | Comments (5)
2010 August 30 Monday
Genetic Basis For Whether To Respond To Surveys

If you ignore surveys in the mail and hang up on surveyors on the phone your genes are telling you to do it. Next time a phone surveyor calls up I'm going to tell them "My genes compel me to hang up on you". So I've got that to look forward to.

A new study from North Carolina State University shows that genetics play a key factor in whether someone is willing to take a survey.

“We wanted to know whether people are genetically predisposed to ignore requests for survey participation,” says Dr. Lori Foster Thompson, an associate professor of psychology at NC State and lead author of a paper describing the research. “We found that there is a pretty strong genetic predisposition to not reply to surveys.”

For the study, the researchers sent out a survey to over 1,000 sets of twins – some fraternal, some identical – and then measured who did and did not respond. The researchers were interested in whether the response behavior of one twin accurately predicted the behavior of the other twin. “We found that the behavior of one identical twin was a good predictor for the other,” Foster Thompson says, “but that the same did not hold true for fraternal twins.

Naturally I wonder what that propensity to ignore surveys correlates with. What faction of politics or culture is being missed by surveyors? What kinds of people do you think are least likely to answer surveys? What other traits does this propensity track with? Shyness? The tendency to be a loner? Independence? Resentment of authority? Lack of charitable feeling?

Also, are the people who won't answer phone surveys the same as the ones who won't answer mail surveys? Phone's a lot more invasive and personal. So phone surveyors might repel a different subset of humanity.

By Randall Parker    2010 August 30 09:30 PM   Entry Permalink | Comments (1)
2009 November 17 Tuesday
Less Fearful Babies More Likely To Become Criminals

Babies less prone to feel fear are more likely to commit crimes.

Even at the tender age of 3, children who will go on to be convicted of a crime are less likely to learn to link fear with a certain noise than those who don't. This may mean that an insensitivity to fear could be a driving force behind criminal behaviour.

Adult criminals tend to be fearless, but whether this characteristic emerges before or after they commit a crime wasn't clear, says Adrian Raine, a psychologist at the University of Pennsylvania in Philadelphia.

Will people choosing genetic alleles for their genetically engineered children make them more or less predisposed to feel fear than the average human today? The answer will at least partially determine whether embryo selection for preferred genes will make future humans more or less criminal than they are today.

Raine does a lot of interesting work on innate causes of behavior. See my posts Brain Scans Show Abnormalities In Psychopaths and Habitual Liar Brains Look Different On Scans for more interesting brain research from Raine.

By Randall Parker    2009 November 17 10:12 PM   Entry Permalink | Comments (7)
2009 November 01 Sunday
Facial Proportions Show Aggressiveness

You've heard that we shouldn't judge people by their appearances and that appearances are only skin deep. Well no. People can predict the aggressiveness of other people after viewing their facial pictures for less than a second.

Angry words and gestures are not the only way to get a sense of how temperamental a person is. According to new findings in Psychological Science, a journal of the Association for Psychological Science, a quick glance at someone's facial structure may be enough for us to predict their tendency towards aggression.

Facial width-to-height ratio (WHR) is determined by measuring the distance between the right and left cheeks and the distance from the upper lip to the mid-brow. During childhood, boys and girls have similar facial structures, but during puberty, males develop a greater WHR than females. Previous research has suggested that males with a larger WHR act more aggressively than those with a smaller WHR. For example, studies have shown that hockey players with greater WHR earn more penalty minutes per game than players with lower WHR.

Psychologists Justin M. Carré, Cheryl M. McCormick, and Catherine J. Mondloch of Brock University conducted an experiment to see if it is possible to predict another person's propensity for aggressive behavior simply by looking at their photograph. Volunteers viewed photographs of faces of men for whom aggressive behavior was previously assessed in the lab. The volunteers rated how aggressive they thought each person was on a scale of one to seven after viewing each face for either 2000 milliseconds or 39 milliseconds.

We have the innate ability to read faces and know things about a person's personality.

The photographs were very revealing: Volunteers' estimates of aggression correlated highly with the actual aggressive behavior of the faces viewed, even if they saw the picture for only 39 milliseconds. Even more interestingly, the volunteers' estimates were also highly correlated with WHR of the faces—the greater the WHR, the higher the aggressive rating, suggesting that we may use this aspect of facial structure to judge potential aggression in others. These findings indicate that subtle differences in face shape may affect personality judgments, which may, in turn, guide how we respond to certain individuals.

Some day these results will lead to an important offspring genetic engineering question: Genetically engineer your kid to look more aggressive than he is in order to intimidate would-be challengers? Or genetically engineer him (or her) to look meek while being ready, willing, and able to aggressively pursue goals?

You don't want to engineer your kid to be physically aggressive but weak or poorly coordinated. Though it'll probably be possible to genetically engineer more for an aggressiveness useful for success in business and less for aggressiveness that leads to time in prison for assault and murder.

Update: Most personality traits are readable from facial expressions. We really are open books.

AUSTIN, Texas—First impressions do matter when it comes to communicating personality through appearance, according to new research by psychologists Laura Naumann of Sonoma State University and Sam Gosling of The University of Texas at Austin.

Despite the crucial role of physical appearance in creating first impressions, until now little research has examined the accuracy of personality impressions based on appearance alone. These findings will be published in the December 2009 issue of Personality and Social Psychology Bulletin, co-written with Simine Vazire (Washington University in St. Louis) and Peter J. Rentfrow (University of Cambridge).

"In an age dominated by social media where personal photographs are ubiquitous, it becomes important to understand the ways personality is communicated via our appearance," says Naumann. "The appearance one portrays in his or her photographs has important implications for their professional and social life."

In the study, observers viewed full-body photographs of 123 people they had never met before. The targets were viewed either in a controlled pose with a neutral facial expression or in a naturally expressed pose. The accuracy of the judgments was gauged by comparing them to the aggregate of self-ratings and that of three informants who knew the targets well, a criterion now widely regarded as the gold standard in personality research.

Even when viewing the targets in the controlled pose, the observers could accurately judge some major personality traits, including extraversion and self-esteem. But most traits were hard to detect under these conditions. When observers saw naturally expressive behavior (such as a smiling expression or energetic stance), their judgments were accurate for nine of the 10 personality traits. The 10 traits were extraversion, agreeableness, conscientiousness, emotional stability, openness, likability, self-esteem, loneliness, religiosity and political orientation.

Does the personality shape the face? Or do genetic factors shape them both?

By Randall Parker    2009 November 01 04:23 PM   Entry Permalink | Comments (1)
2009 September 01 Tuesday
Emotional Music For Tamarin Monkeys

Mozart doesn't speak to them. Beethoven didn't have them in mind. Bach was writing to a more ascended audience. Go hear and listen to music composed for tamarin monkeys.

What I wonder: would another species on some other planet which has achieved industrial civilization (assuming such a species exists) find our greatest compositions appealing? Would they find Elvira Madigan or the Emperor Concerto or perhaps Cappricio Espanol enjoyable or uplifting?

By Randall Parker    2009 September 01 09:47 PM   Entry Permalink | Comments (1)
2009 August 30 Sunday
Amygdala Controls Personal Space Distance

The amygdala in your brain determines the distance you prefer for people standing near you. The ability to manipulate the brain to adjust this distance would have practical applications such as with manned space flight.

Pasadena, Calif.—In a finding that sheds new light on the neural mechanisms involved in social behavior, neuroscientists at the California Institute of Technology (Caltech) have pinpointed the brain structure responsible for our sense of personal space.

The discovery, described in the August 30 issue of the journal Nature Neuroscience, could offer insight into autism and other disorders where social distance is an issue.

The structure, the amygdala—a pair of almond-shaped regions located in the medial temporal lobes—was previously known to process strong negative emotions, such as anger and fear, and is considered the seat of emotion in the brain. However, it had never been linked rigorously to real-life human social interaction.

A woman with a damaged amygdala provides insight into its function.

The scientists, led by Ralph Adolphs, Bren Professor of Psychology and Neuroscience and professor of biology and postdoctoral scholar Daniel P. Kennedy, were able to make this link with the help of a unique patient, a 42-year-old woman known as SM, who has extensive damage to the amygdala on both sides of her brain.

"SM is unique, because she is one of only a handful of individuals in the world with such a clear bilateral lesion of the amygdala, which gives us an opportunity to study the role of the amygdala in humans," says Kennedy, the lead author of the new report.

This woman is less able to recognize fear in the faces of others and prefers to stand closer to people than they feel comfortable with.

SM has difficulty recognizing fear in the faces of others, and in judging the trustworthiness of someone, two consequences of amygdala lesions that Adolphs and colleagues published in prior studies.

During his years of studying her, Adolphs also noticed that the very outgoing SM is almost too friendly, to the point of "violating" what others might perceive as their own personal space. "She is extremely friendly, and she wants to approach people more than normal. It's something that immediately becomes apparent as you interact with her," says Kennedy.

SM is comfortable with standing nose-to-nose with another person.

The experiment used what is known as the stop-distance technique. Briefly, the subject (SM or one of 20 other volunteers, representing a cross-section of ages, ethnicities, educations, and genders) stands a predetermined distance from an experimenter, then walks toward the experimenter and stops at the point where they feel most comfortable. The chin-to-chin distance between the subject and the experimenter is determined with a digital laser measurer.

Among the 20 other subjects, the average preferred distance was .64 meters—roughly two feet. SM's preferred distance was just .34 meters, or about one foot. Unlike other subjects, who reported feelings of discomfort when the experimenter went closer than their preferred distance, there was no point at which SM became uncomfortable; even nose-to-nose, she was at ease. Furthermore, her preferred distance didn't change based on who the experimenter was and how well she knew them.

Think about the uses if one could suppress the feeling of discomfort in close quarters. Smaller personal space size would have obvious advantages for manned space flight. Going to take a many month trip to Mars? The ability to shrink personal space preferences would enable more relaxed feelings in smaller quarters.

Mines, submarines, even college dorms and subways put people very close to each other - uncomfortably close for many. Do you find yourself in situations where you'd like to be able to dial down your discomfort from being physically close to others?

By Randall Parker    2009 August 30 09:42 PM   Entry Permalink | Comments (8)
2009 August 14 Friday
Human Brain Classifies Images By Whether Living

Human brains treat living and non-living objects very differently. The brain has different regions for processing images of living and non-living.

For unknown reasons, the human brain distinctly separates the handling of images of living things from images of non-living things, processing each image type in a different area of the brain. For years, many scientists have assumed the brain segregated visual information in this manner to optimize processing the images themselves, but new research shows that even in people who have been blind since birth the brain still separates the concepts of living and non-living objects.

The research, published in today's issue of Neuron, implies that the brain categorizes objects based on the different types of subsequent consideration they demand—such as whether an object is edible, or is a landmark on the way home, or is a predator to run from. They are not categorized entirely by their appearance.

Only living things (or formerly living things) are food. Only living things will attack or run away. From the standpoint of basic survival it is not surprising our brains treat living things in fundamentally different ways. I suspect as a result of our evolutionary legacy we are overly biased toward thinking about living things. Due to a greater specialization of labor lots of us have jobs that involve working with non-living things such as designing and building objects. Maybe hunting as a sport is born out of a desire to fill a need in the mind to think about living things. Are men who work with non-living things more likely to hunt?

Even people blind from birth categorize living and non-living objects in different ways detectable via MRI brain scans.

To see if the appearance of objects is indeed key to how the brain conducts its processing, Mahon and his team, led by Alfonso Caramazza, director of the Cognitive Neuropsychology Laboratory at Harvard University, asked people who have been blind since birth to think about certain living and non-living objects. These people had no visual experience at all, so their brains necessarily determined where to do the processing using some criteria other than an object's appearance.

"When we looked at the MRI scans, it was pretty clear that blind people and sighted people were dividing up living and non-living processing in the same way," says Mahon. "We think these findings strongly encourage the view that the human brain's organization innately anticipates the different types of computations that must be carried out for different types of objects."

The researchers are looking for more ways to identify other innate processes of thinking.

Update: In the comments someone mentioned how people give nicknames to their iRobot Roomba vacuum cleaner robots. I've read the same about US soldiers with their battlefield robots in Iraq. So I wonder: When you look at these pictures of robot vacuums do you feel you are looking at things that are in any way at least partially living?

So what's your emotional reaction?

I expect robots for kids to get classified by their brains as living things. South Park's AWESOM-O episode of Eric Cartman pretending to be a robot to Butters shows the future.

An innate tendency of humans to classify robots as living could lead us to create robots that we give rights to.

By Randall Parker    2009 August 14 08:23 AM   Entry Permalink | Comments (5)
2009 July 21 Tuesday
Babies Understand Dogs

We are all Dr. Doolittle as babies.

New research shows babies have a handle on the meaning of different dog barks – despite little or no previous exposure to dogs.

Infants just 6 months old can match the sounds of an angry snarl and a friendly yap to photos of dogs displaying threatening and welcoming body language.

The new findings come on the heels of a study from the same Brigham Young University lab showing that infants can detect mood swings in Beethoven’s music.

But can babies tell when politicians are lying? Or maybe they can predict the stock market but we just haven't figured out yet how to ask them. Or maybe they understand equations for achieving controlled nuclear fusion? Just what all do babies understand, anyhow?

By Randall Parker    2009 July 21 05:36 PM   Entry Permalink | Comments (2)
2009 May 20 Wednesday
Super-Recognizers Great At Facial Recognition

These people should be paid to scan crowds for criminals.

CAMBRIDGE, Mass., May 19, 2009 – Some people say they never forget a face, a claim now bolstered by psychologists at Harvard University who've discovered a group they call "super-recognizers": those who can easily recognize someone they met in passing, even many years later.

The new study suggests that skill in facial recognition might vary widely among humans. Previous research has identified as much as 2 percent of the population as having "face-blindness," or prosopagnosia, a condition characterized by great difficulty in recognizing faces. For the first time, this new research shows that others excel in face recognition, indicating that the trait could be on a spectrum, with prosopagnosics on the low end and super-recognizers at the high end.

The research is published in Psychonomic Bulletin & Review, and was led by Richard Russell, a postdoctoral researcher in the Department of Psychology at Harvard, with co-authors Ken Nakayama, Edgar Pierce Professor of Psychology at Harvard, and Brad Duchaine of the University College London.

The research involved administering standardized face recognition tests. The super-recognizers scored far above average on these tests—higher than any of the normal control subjects.

Imagine employing super-recognizers to watch for criminals in train stations, airports, and other places where large numbers of people pass. These are the people we should want to look at most wanted lists of criminals.

If you could choose among cognitive traits to give to offspring would you place super-recognizer capability high or low in a list of priorities?

By Randall Parker    2009 May 20 11:26 PM   Entry Permalink | Comments (7)
2009 March 19 Thursday
Recognition Of Emotions In Music Seen As Innate Skill

We are wired up to recognize certain types of music as expressing particular human emotions.

Native African people who have never even listened to the radio before can nonetheless pick up on happy, sad, and fearful emotions in Western music, according to a new report published online on March 19th in Current Biology, a Cell Press publication. The result shows that the expression of those three basic emotions in music can be universally recognized, the researchers said.

"These findings could explain why Western music has been so successful in global music distribution, even in music cultures that do not as strongly emphasize the role of emotional expression in their music," said Thomas Fritz of the Max-Planck-Institute for Human Cognitive and Brain Sciences.

The expression of emotions is a basic feature of Western music, and the capacity of music to convey emotional expressions is often regarded as a prerequisite to its appreciation in Western cultures, the researchers explained. In other musical traditions, however, music is often appreciated for other qualities, such as group coordination in rituals.

You've got the music in you.

By Randall Parker    2009 March 19 11:14 PM   Entry Permalink | Comments (3)
2009 February 15 Sunday
We Consistently Map Faces To Personality Types

Do we know what we are doing when we classify people into personality types by looking at their faces?

First impressions are highly influential, despite the well-worn admonition not to judge a book by its cover. Within a tenth of a second of seeing an unfamiliar face we have already made a judgement about its owner's character - caring, trustworthy, aggressive, extrovert, competent and so on (Psychological Science, vol 17, p 592). Once that snap judgement has formed, it is surprisingly hard to budge. What's more, different people come to strikingly similar conclusions about a particular face - as shown in our own experiment (see "The New Scientist face experiment").

People also act on these snap judgements. Politicians with competent-looking faces have a greater chance of being elected, and CEOs who look dominant are more likely to run a profitable company. Baby-faced men and those with compassionate-looking faces tend to be over-represented in the caring professions. Soldiers deemed to look dominant tend to rise faster through the ranks, while their baby-faced comrades tend to be weeded out early. When baby-faced men appear in court they are more likely than their mature-faced peers to be exonerated from a crime. However, they are also more likely to be found guilty of negligence.

While we have clear tendencies to expect different facial appearances to be associated with different kinds of personalities the article reports that scientists are still uncertain as to how accurate our judgments are about faces and personalities.

When offspring genetic engineering becomes possible will people choose to make the faces of their kids look trustworthy and dominant?

By Randall Parker    2009 February 15 11:19 PM   Entry Permalink | Comments (0)
2009 January 01 Thursday
Facial Expressions Are Innate For Expressing Emotions

We do not learn to associate emotions with contorting our faces in particular ways.

San Francisco State University Psychology Professor David Matsumoto compared the facial expressions of sighted and blind judo athletes at the 2004 Summer Olympics and Paralympic Games. More than 4,800 photographs were captured and analyzed, including images of athletes from 23 countries.

"The statistical correlation between the facial expressions of sighted and blind individuals was almost perfect," Matsumoto said. "This suggests something genetically resident within us is the source of facial expressions of emotion."

Matsumoto found that sighted and blind individuals manage their expressions of emotion in the same way according to social context. For example, because of the social nature of the Olympic medal ceremonies, 85 percent of silver medalists who lost their medal matches produced "social smiles" during the ceremony. Social smiles use only the mouth muscles whereas true smiles, known as Duchenne smiles, cause the eyes to twinkle and narrow and the cheeks to rise.

I expect we will eventually have imaging processing software that we can use when watching politicians and other figures on TV that would let us know things like when we are seeing social smiles versus Duchenne smiles. Automated emotional interpretation such as lie detection by facial expression reading

The high point in belief that environment is the source of all behavior was reached a long time ago with B.F. Skinner. I can't believe the guy was ever taken seriously.

By Randall Parker    2009 January 01 12:52 AM   Entry Permalink | Comments (6)
Fewer Dopamine Receptors Means More Novelty Seeking

Thrill seeking and increased risk of drug abuse might stem from having fewer of a type of dopamine receptor.

NASHVILLE, Tenn.--For risk-takers and impulsive people, New Year's resolutions often include being more careful, spending more frugally and cutting back on dangerous behavior, such as drug use. But new research from Vanderbilt finds that these individuals--labeled as novelty seekers by psychologists--face an uphill battle in keeping their New Year's resolutions due to the way their brains process dopamine. The research reveals that novelty seekers have less of a particular type of dopamine receptor, which may lead them to seek out novel and exciting experiences--such as spending lavishly, taking risks and partying like there's no tomorrow.

The research was published Dec. 31, 2008, in the Journal of Neuroscience.

The neurotransmitter dopamine is produced by a select group of cells in the brain. These dopamine-producing cells have receptors called autoreceptors that help limit dopamine release when these cells are stimulated.

"We've found that the density of these dopamine autoreceptors is inversely related to an individual's interest in and desire for novel experiences," David Zald, associate professor of psychology and lead author of the study, said. "The fewer available dopamine autoreceptors an individual has, the less they are able to regulate how much dopamine is released when these cells are engaged. Because of this, novelty and other potentially rewarding experiences that normally induce dopamine release will produce greater dopamine release in these individuals."

The researchers used positron emission topography (PET) brain scans to help them reach this conclusion.

The researchers used positron emission topography to view the levels of dopamine receptors in 34 healthy humans who had taken a questionnaire that measured the novelty-seeking personality trait. The questionnaire measured things such as an individual's preference for and response to novelty, decision-making speed, a person's readiness to freely spend money, and the extent to which a person is spontaneous and unconstrained by rules and regulations. The higher the score, the more likely the person was to be a novelty seeker.

The researchers found that those that scored higher on the novelty-seeking scale had decreased dopamine autoreceptor availability compared to the subjects that scored lower.

If it becomes possible to use a drug to increase the number of dopamine autoreceptors will some thrill-seekers or perhaps some drug abusers opt to change their brain in such a fundamental way in order to gain greater ability to control and restrict their own actions? I can imagine compulsive spenders opting for such a treatment. But skiers, skydivers, and other thrill seekers might decide they'd rather continue to pursue extreme sports.

By Randall Parker    2009 January 01 12:48 AM   Entry Permalink | Comments (2)
2008 October 26 Sunday
People Can Estimate Male Strength From Face Pictures

Our brains can estimate upper body strength for fighting just from facial pictures. The idea here is that our ancestors needed to know when to fight or back off. So we have this innate ability.

(Santa Barbara, Calif.) –– For our ancestors, misjudging the physical strength of a would-be opponent might have resulted in painful –– and potentially deadly –– defeat.

Now, a study conducted by a team of scientists at the University of California, Santa Barbara has found that a mechanism exists within the human brain that enables people to determine with uncanny accuracy the fighting ability of men around them by honing in on their upper body strength. What's more, that assessment can be made even when everything but the men's faces are obscured from view. A paper highlighting the researchers' findings appears in the current issue of the Proceedings of the Royal Society.

"Assessing fighting ability was important for our ancestors, and the characteristic that the mind implicitly equates with fighting ability is upper body strength," said Aaron Sell, a postdoctoral fellow at UCSB's Center for Evolutionary Psychology and the paper's lead author. "That's the component of strength that's most relevant to premodern combat. The visual assessment of fighting ability is almost perfectly correlated with the perception of strength, and both closely track actual upper body strength. What is a bit spooky is that upper body strength can even be read on a person's face.

Maybe facial muscles get built up along with upper chest and arm muscles? Or necks become thicker? Or testosterone levels determine average muscularity as well as extent of masculine features in faces such as thick bone above the eyes.

Some major names in evolutionary psychology (Cosmides and Tooby at UCSB) were involved in this work.

Sell conducted the study with Leda Cosmides, a professor of psychology and co-director of the Center for Evolutionary Psychology; John Tooby, a professor of anthropology and also co-director of the Center for Evolutionary Psychology; Michael Gurven, an associate professor of anthropology; and graduate students Daniel Sznycer and Christopher von Rueden.

Perception of fighting ability as guessed from facial pictures correlated with measured upper body weight lifting capacity.

When the photographs depicted men whose strength had been measured precisely on weight-lifting machines, the researchers found an almost perfect correlation between perceptions of fighting ability and perceptions of strength. "When you see that kind of correlation it's telling you you're measuring the same underlying variable," said Tooby.

They also found that perceptions of strength and fighting ability reflected the target's actual strength, as measured on weight-lifting machines at the gym. In other sections of the study, the researchers showed that this result extended far beyond the gym. Both men and women accurately judge men's strength, whether those men are drawn from a general campus population, a hunter-horticulturalist group in Bolivia, or a group of herder-horticulturalists living in the Argentinian Andes.

Imagine future humans whose upper body strength and facial features become basically disconnected from each other (that can already happen with steroid usage). Innate ability to generalize from facial features won't always work. But there's not an obvious genetic fix to do for future offspring since the current rules that our brain uses will still work for some people and any genetic change in how we analyze facial features will just change which humans we make the errors about. Maybe future humans will just remove that capability in their offspring.

By Randall Parker    2008 October 26 06:56 PM   Entry Permalink | Comments (16)
2008 August 05 Tuesday
Characteristics Of Trusted Face Discovered

Here's another research result that will some day guide prospective parents who want to select and modify embryos to guarantee the success of their kids. Our brains are wired up to find certain facial shapes as more trustworthy.

A pair of Princeton psychology researchers has developed a computer program that allows scientists to analyze better than ever before what it is about certain human faces that makes them look either trustworthy or fearsome. In doing so, they have also found that the program allows them to construct computer-generated faces that display the most trustworthy or dominant faces possible.

Such work could have implications for those who care what effect their faces may have upon a beholder, from salespeople to criminal defendants, the researchers said.

In a paper appearing in the online edition this week of the Proceedings of the National Academy of Sciences, Alexander Todorov, an assistant professor of psychology and public affairs at Princeton, and Nikolaas Oosterhof, a research specialist, continue an inquiry into the myriad messages conveyed by the human face. In 2005, Todorov's lab garnered international headlines with a study published in Science demonstrating that quick facial judgments can accurately predict real-world election results.

This opens up the possibility that Hollywood casting agents could use software to go through large numbers of photos to discover, for example, faces that would make for fearsome dictators or slashers or evil spies.

A U-shaped mouth and an almost surprised look to the eyes maximize feelings of trustworthiness. Eyebrows close to the eyes project a dominant look.

From there, using a commercial software program that generates composites of human faces (based on laser scans of real subjects), the scientists asked another group of test subjects to look at 300 faces and rate them for trustworthiness, dominance and threat. Common features of both trustworthiness and dominance emerged. A trustworthy face, at its most extreme, has a U-shaped mouth and eyes that form an almost surprised look. An untrustworthy face, at its most extreme, is an angry one with the edges of the mouth curled down and eyebrows pointing down at the center. The least dominant face possible is one resembling a baby's with a larger distance between the eyes and the eyebrows than other faces. A threatening face can be obtained by averaging an untrustworthy and a dominant face.

With the ability to predict reactions to faces comes the ability to design faces to maximize desired reactions. Want to design a dominant and highly trusted face for a future leader?

Using the program and the ratings from subjects, the scientists could actually construct models of how faces vary on these social dimensions. Once those models were established, the scientists could exaggerate faces along these dimensions, show them to other test subjects to confirm that they were eliciting the predicted emotional response, and find out what facial features are critical for different social judgments.

Within 20 years if not sooner offspring genetic engineering will be used to choose appearances of offspring. Imagine the possibilities. Ambitious parents who want their kids to become CEOs and high elected officials will select embryos that will grow up to to become adults with facial appearances and body shapes that maximize their potential to dominate and control others.

Are faces that elicit feelings of trust really more trustworthy? Why would our genes that cause that reaction have been selected for unless that reaction was justified?

By Randall Parker    2008 August 05 08:42 PM   Entry Permalink | Comments (3)
2006 June 17 Saturday
Angry Male Faces Noticed Most Rapidly

Angry men stand out in a crowd.

By comparing how quickly human facial expressions of different types are detected in a crowd of neutral faces, researchers have demonstrated that male angry faces are a priority for visual processing – particularly for male observers. The findings are reported by Mark Williams of the Massachusetts Institute of Technology and Jason Mattingley of the University of Melbourne, Australia, and appear in the June 6th issue of Current Biology.

In evolutionary terms, it makes sense that our attention is attracted by threat in the environment. It has long been hypothesized that facial expressions that signal potential threat, such as anger, may capture attention and therefore "stand out" in a crowd. In fact, there are specific brain regions that are dedicated to processing threatening facial expressions. Given the many differences between males and females, with males being larger and more physically aggressive than females, one might also suspect differences in the way in which threat is detected from individuals of different genders.

In the new work, Williams and Mattingley show that angry male faces are found more rapidly than angry female faces by both men and women. In addition, men find angry faces of both genders faster than women, whereas women find socially relevant expressions (for example, happy or sad) more rapidly. The work suggests that although males are biased toward detecting threatening faces, and females are more attuned to socially relevant expressions, both sexes prioritize the detection of angry male faces; in short, angry men get noticed. The advantage for detecting angry male faces is consistent with the notion that human perceptual processes have been shaped by evolutionary pressures arising from the social environment.

Angry males are a greater potential threat than angry females. So it makes sense that natural selection would favor a wiring of human brains that make them more easily recognized.

There's a security angle here: Secret Service and other professional bodyguard outfits that need to recognize angry male would-be assassins might do that job better with male agents. However, do assassins look and feel angry? Or are some feeling thrills at what they are about to do? If assassins express other kinds of emotions when preparing to kill then maybe women would be better at recognizing them.

What I wonder: Just how many distinct adaptations and abilities has natural selection wired into human brains? How many of those abilities are trade-offs with other abilities? For example, in the case above while males have an advantage recognizing angry faces females have an advantage in decoding the meaning of other facial expressions.

Also, once scientists identify which genetic variations make those abilities more or less pronounced which abilities will people choose to give their offspring? I think the question of how people will genetically engineer their offspring is one of the most important questions we face for the future.

By Randall Parker    2006 June 17 07:42 AM   Entry Permalink | Comments (1)
2005 March 22 Tuesday
Stimulaton Of Primate Brains Show Many Complex Behaviors Are Innate

The set of behaviors that are thought to be innate rather than learned continues to expand.

Vanderbilt researchers, writing this week in the Proceedings of the National Academy of Sciences Online Early Edition, report that they can elicit these complex behaviors by stimulating specific areas in the brain of a small nocturnal primate called the Galago or bush baby (Otolemur garnetti). Their results provide significant new support for the proposition that all primate brains, including our own, contain such a repertoire of innate complex behaviors.

"We have now seen this feature in the brain of an Old World monkey and New World prosimian. The fact that it appears in the brains of two such divergent primates suggests that this form of organization evolved very early in the development of primates. That, in turn, suggests that it is characteristic of all primate brains, including the human brain," says Jon Kaas, the head of the research group, Distinguished Professor of Psychology at Vanderbilt University and investigator at the Vanderbilt Kennedy Center for Research on Human Development.

"These results explain why certain behaviors – such as defensive and aggressive movements, smiling and grasping food – are so similar around the world. It is because the instructions for these movements are built-in and not learned," he adds.

Over the last 20 years, neuroscientists have identified an area called the primary motor cortex, which, when stimulated, triggers simple muscle movements. The fact that they were able to produce only motions by single muscles and other simple movements reinforced the idea that only simple movements were hard-wired into primate brain circuitry.

Then, last year Michael Graziano at Princeton University pointed out that previous stimulation experiments in the motor cortex – the area that controls bodily motions – had been done using very short electrical pulses that last less than a half-second. He further suggested that longer pulses might stimulate more complicated motions. Working with alert macaques, he and his colleagues found that applying such long-duration signals did in fact elicit several of these complex behaviors, much as they had predicted.

Kaas and his colleagues, research assistant professor Iwona Stepniewska and doctoral student Pei-Chun Fang, decided to follow the Princeton researchers' lead and try long-duration stimuli in the simpler brain of the Galago. When they did, they also found that this type of stimuli triggered complex behaviors. In fact, they were able to stimulate a larger number of complex movements than the Princeton group had reported, including aggressive facial patterns, defensive forelimb movements, and hand-to-mouth and reaching-and-grasping movements.

The Princeton researchers stimulated areas in the motor cortex. The Vanderbilt researchers found that they could also elicit these behaviors by stimulating a nearby area of the brain called the posterior parietal cortex. This area is heavily interconnected with the motor cortex and had previously been associated with transforming data from the eyes and other senses into a spatial map of the surrounding environment. The new findings reveal that this brain area also plays an important role in complex, innate behaviors.

If a behavior is innate then some day it will become genetically reprogrammable. The reprogramming will be easier to do in embryos than in fully developed humans. A lot of the genetic coding that controls behavior does so by controlling development. Just what choices people will make once they can control the genetic coding of their offspring is one of the most important questions of the 21st century.

Even before offspring genetic engineering becomes possible the discoveries of more genetic causes of human behavior is going to lead to massive rethinks in how we approach child rearing, teaching, criminal justice, decisions about reproduction, and many other aspects of human life. Should a person who is genetically prone to violence be seen as morally responsible for his actions? Is that a reason not to imprison him? Or will people put their own safety first (which is what I'm guessing) and demand that if a violent guy can't help himself should he be jailed for a longer period of time? Also, if he can be identified as violent while still in childhood should be he isolated before he first murders or rapes?

By Randall Parker    2005 March 22 01:20 PM   Entry Permalink | Comments (9)
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