PSYCHOLOGY

[World Science, July 28, 2005]

How alike are you and your husband or wife — or, you and your best friend? Probably more alike than you realize, a new study has found.

The study of twins shows that people’s spouses and best friends are genetically about as close as brothers and sisters, the researchers said. The results also suggested that the preference for partners who are similar to us is partly due to our genes. J. Philippe Rushton and Trudy Ann Bons of the University of Western Ontario in London, Ontario, reported the findings in the July issue of Psychological Science, a journal of the American Psychological Society.

Several hundred pairs of identical and fraternal twins, their spouses, and their best friends were sent a 130-item questionnaire that measured social background, personality, and attitudes. Twins turned out to be as similar to their spouses and friends as they were to their fraternal twins, though not as similar as they were to identical twins, the researchers reported.

The spouses of identical twins (who share 100 percent of their genes) were also more similar to each other than were the spouses of fraternal twins (who only share 50 percent of their genes); the same was true of twins’ best friends.

The researchers compared the genetic and environmental effects on partner choice among identical twins. They found that preference for spouses and friends similar to themselves was about 34 percent due to participants’ shared genes, 12 percent due to their common environment, and 54 percent due to factors in their unique (non shared) environment. This shows there is a sizeable genetic component to our tendency to seek out people like ourselves, they said.

The researchers also found that the greatest self-similarity between people and their partners and friends was on the more heritable items in the questionnaire. For example, “enjoying reading” had a relatively high level of 41 percent heritability, while preferring to “travel the world alone” was only 24 percent heritable.

“From arrays of possible alternatives, people seek those compatible” with their genes, the authors wrote. “People prefer their own kind — extroverts favour extroverts; traditionalists, traditionalists.” Unconsciously favouring heritable criteria in choosing our mates supports evolutionary psychology’s theory that social preferences follow genetic similarities, the researchers claimed.

“If you like, become friends with, come to the aid of, and mate with those people who are genetically most similar to yourself, you are simply trying to ensure that your own segment of the gene pool will be safely maintained and eventually transmitted to future generations,” the authors wrote.

Some researchers have also proposed that preferences for genetically similar partners helps drive the evolution of new species across the animal world. Rushton noted that the results joined a host of recent research showing that both genes and upbringing influence human behaviour. “It is especially interesting to see that this applies to our preferences for mates and friendships,” he said. “Choosing a life partner is one of the most important decisions that we make.”

However, Rushton cautioned against over-interpretation of the results. “We found that more than half of the variance in this study was due to unique environmental effects such as being in the right place at the right time.” He added, “Similarity is only one of many factors in choosing a partner.”

[October ,225]

A study has found brain abnormalities in people who habitually lie, cheat and manipulate others.

Previous research had shown that when normal people lie, there is heightened activity in the prefrontal cortex, a brain area that enables most people to feel remorse or learn moral behavior. The new study showed that the same brain area, just behind the forehead, exhibits structural differences among pathological liars, said the researchers.

The study, led by Yaling Yang and Adrian Raine of the University of Southern California, in Los Angeles, appears in the October issue of the British Journal of Psychiatry. The researchers analyzed the brains of 49 people, a group drawn from temporary employees in the city who had volunteered to participate.

Psychological tests and interviews placed 12 in the category of people who had a history of repeated lying (11 men, one woman); 16 who exhibited signs of antisocial personality disorder but not pathological lying (15 men, one woman); and 21 who were normal controls (15 men, six women).

“We looked for things like inconsistencies in their stories about occupation, education, crimes and family background,” said Raine. “Pathological liars can’t always tell truth from falsehood and contradict themselves in an interview. They are manipulative and they admit they prey on people. They are very brazen in terms of their manner, but very cool when talking about this. Aside from having histories of conning others or using aliases, the habitual liars also admitted to malingering, or telling falsehoods to obtain sickness benefits.”

After they were categorized, the researchers used a brain imaging technique, Magnetic Resonance Imaging, to explore structural brain differences between the groups. The liars had significantly more “white matter” and slightly less “gray matter” than those they were measured against.

White matter consists mostly of the tentacle-like extensions of brain cells, which the cells use to communicate with each other. Gray matter is mostly the main bodies of the cells themselves. Liars had a 25.7 percent more white matter in the prefrontal cortex than antisocial controls and a 22 percent increase more than the normal controls, the researchers found. Liars had a 14.2 percent decrease in prefrontal gray matter compared to normal controls. More white matter – the wiring in the brain – may provide liars with the tools necessary to master the complex art of deceit, Raine said.

“Lying takes a lot of effort,” he said. “It’s almost mind reading. You have to be able to understand the mindset of the other person. You also have to suppress your emotions or regulate them because you don’t want to appear nervous. There’s quite a lot to do there. You’ve got to suppress the truth. “Our argument is that the more networking there is in the prefrontal cortex, the more the person has an upper hand in lying. Their verbal skills are higher. They’ve almost got a natural advantage.”

But in normal people, it’s the gray matter – or the brain cells connected by the white matter – that helps keep the impulse to lie in check. Pathological liars have a surplus of white matter, the study found, and a deficit of gray matter. That means they have more tools to lie coupled with fewer moral restraints than normal people.

“They’ve got the equipment to lie, and they don’t have the disinhibition that the rest of us have in telling the big whoppers,” Raine said. “When people make moral decisions, they are relying on the prefrontal cortex. When people ask normal people to make moral decisions, we see activation in the front of the brain,” he explained. “If these liars have a 14 percent reduction in gray matter, that means that they are less likely to care about moral issues or are less likely to be able to process moral issues. Having more gray matter would keep a check on these activities.”

The researchers stopped short of asserting that these structural differences account for all lying. “This is one of the components,” Raine said. “The findings need to be replicated and extended to other parts of the brain. What are the other neurobiological processes? We haven’t had studies like this. It’s exciting to us because it’s a beginning study, but we need a lot more to flesh out this discovery.”

Yang, the study’s lead author, said the findings eventually could be used in making clinical diagnoses and may have applications in the criminal justice system and the business world. “If [the findings] can be replicated and extended, they may have long-term implications in a number of areas,” said Yang, a doctoral student.

“For example, in the legal system they could potentially be used to help police work out which suspects are lying. In terms of clinical practice, they could help clinicians diagnose who is malingering – making up disability for financial gain. “And also in business, they could assist in pre-employment screening, working out which individuals may not be suitable for hiring. But, right now, I have to emphasize that there are no direct practical applications,” she said.

In their journal article, the authors note that separate studies of autistic children – who typically have trouble lying – have showed the converse pattern of gray matter/white matter ratios. “The facts that autistic children have difficulty lying and also show reduced prefrontal white matter constitutes the opposite but complementary pattern” to the findings in the new study, the researchers wrote. “Although autism is a complex condition and cannot be taken as a model for lying, these results … converge with current findings on adult liars in suggesting that the prefrontal cortex is centrally involved in the capacity to lie.”

[BBC, August 19, 2005]

The quest to simulate the mammalian brain on the world's most powerful supercomputer is neuroscience's most ambitious project yet. BBC Reporter David Reid went to Lausanne in Switzerland to find out how the line is being blurred between man and machine.

Understanding how neurons work could help with medical treatment Inside your head nestles a forest of millions of neurons which weave together to make your thoughts. Man has long wanted to discover the secrets of the brain, and has done so with varying degrees of success. Recently advancements in this area of science have been limited by the power of computers.

But at Switzerland's École Polytechnique Fédérale de Lausanne, the Blue Brain Project aims to change this by simulating the structures and functions of the brain. The project's head, Professor Henry Markram, says that in the past there was no software environment capable of simulating the brain.

"We haven't had the computing power to really address the complexity of the brain. Why is the brain so complex? We need to be able to do simulations addressing the question of complexity."

Now, Blue Gene, a commercially available supercomputer, will help scientists to peer into the most inscrutable part of ourselves. "We are not trying to build an intelligent device or robot or anything like that," explains Professor Markram. "We are trying to understand the brain, and one pathway is to take our available knowledge of the brain and put it to a test inside a model. That process, we believe, will reveal where our gaps are; what we do understand and what we don't understand."

Easily enough said, but to simulate the brain scientists first have to painstakingly analyse it cell by cell. Blue Gene has 8,000 processors, each representing a virtual neuron. They examine the electrical activity in individual neurons and try to decipher the language they use to talk to each other, and how groups of neurons communicate. Then the conclusions are loaded into the Blue Gene computer, which is pretty brainy itself.

With the information gathered in the lab, each of Blue Gene's processors will be programmed to behave like an individual virtual neuron. Markus Baertschi from IBM, which makes Blue Gene, says: "We've got 8,000 processors all working in parallel, talking to each other. Every processor can simulate one neuron and they can communicate among each other to get to the result of thinking, essentially."

The simulation will first build up, neuron by neuron, a working model of a part of the brain called the neocortical column. The end result of all this research could be useful in predicting how the brain might react to certain drugs and diseases.

Professor Markram adds: "We have to realise that while this circuit gave rise to mammalian intelligence and human cognitive function, and is clearly a very powerful circuit, at the same time a lot of things can go wrong inside that circuit. Ultimately if we really want to understand all the things that can go wrong in that circuit we need to have a very detailed model of that circuit."

But this work does not end with discovering what the matter is with grey matter. Scientists have long wanted to discover the secrets of the brain. Mix brain research with one of the world's most powerful computers and people start wondering about artificial intelligence and whether a computer will ever be conscious or have, as they often appear to, a mind of its own.

Markus Baertschi says that the computing power is not really up to it at the moment. "Yes, we have 8,000 processors here, which communicate very rapidly with each other like the brain, but it's only 8,000. The brain has millions and millions and millions, so we need to get to that same size. But that's only raw power. We then need the knowledge of how to tie these millions of computers together to get to something that works and thinks like a brain does."

There are trillions upon trillions of molecules within a tiny little column of neurons, and to accurately capture them is going to be an immense task. Nobody really understands what consciousness is or how it emerges from a biological level, adds Professor Markram.

"The short answer is: we don't really know. The long answer is we're far away from very detailed simulations. We're going to do cellular level simulations in the first phase of two to three years. Then we'll begin with molecular level simulations of single neurons and synapses.

"But we have to realise that there are trillions upon trillions of molecules within a tiny little column of neurons, and to accurately capture them is going to be an immense task."

While computers are impressive number crunchers, artificial intelligence seems a long way off. In the search for startling insights and genius, for the time being at least, we will just have to exercise our own plentiful brain cells.