Are character traits determined genetically?

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

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

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 standardizes these characteristics.

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

Psychologists say the findings are significant because the stronger the genetic link, the more likely it is that these character traits are carried through a family.

Professor Timothy Bates, of the University of Edinburgh's School of Philosophy, Psychology and Language Sciences, said that the genetic influence was strongest on a person's sense of self-control.

Researchers found that genes affected a person's sense of purpose, how well they get on with people and their ability to continue learning and developing.

Professor Bates added: "Ever since the ancient Greeks, people have debated the nature of a good life and the nature of a virtuous life. Why do some people seem to manage their lives, have good relationships and cooperate to achieve their goals while others do not? Previously, the role of family and the environment around the home often dominated people's ideas about what affected psychological well-being. However, this work highlights a much more powerful influence from genetics."

The study, which builds on previous research that found that happiness is underpinned by genes, is published online in the Journal of Personality.

Source: University of Edinburgh [May 16, 2013]

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Cannabis harms the brain - but that's not the full story

For the first time, scientists have proven that cannabis harms the brain. But the same study challenges previously-held assumptions about use of the drug, showing that some brain irregularities predate drug use. 

Professor Dan Lubman, from Turning Point Alcohol and Drug Centre and Monash University, along with a team of researchers from Melbourne University have conducted a world-first study examining whether these brain abnormalities represent markers of vulnerability to cannabis use. 

“Previous evidence has shown that long-term heavy cannabis use is associated with alterations in regional brain volumes,” Professor Lubman said. 

“Although these changes are frequently attributed to the neurotoxic effects of cannabis, no studies have examined whether structural brain abnormalities are present before the onset of cannabis use until now.” 

To fill this void in present studies, Professor Lubman and his team recruited participants from primary schools in Melbourne, Australia, as part of a larger study examining adolescent emotional development. 

Of the 155 original participants who underwent structural magnetic resonance imaging at age 12, 121 completed a follow-up survey measuring substance use four years later. It was found that by age 16, 28 participants had commenced using cannabis. 

“This is an important developmental period to examine, because although not all individuals who initiate cannabis use during this time will go on to use heavily, early cannabis use has been associated with a range of negative outcomes later in life,” Professor Lubman said. 

Their findings revealed that youth with smaller orbitofrontal cortex (OFC) volumes, part of the frontal lobe of the brain, at age 12 were more likely to have initiated cannabis use by age 16. The volumes of other regions of the brain did not predict later cannabis use. 

“Given the lack of research in this area, we hypothesised that pre-drug use differences would be consistent with the structural abnormalities that have been found in studies of heavy users,” Professor Lubman said. 

“What we found is that only the OFC predicted later cannabis use, suggesting that this particular part of the frontal lobe increases an adolescent’s vulnerability to cannabis use. However, we also found no differences in brain volume in other parts of the brain that we have shown to be abnormal in long-term heavy cannabis users, confirming for the first time, that cannabis use is neurotoxic to these brain areas in humans.” 

The OFC plays a primary role in inhibitory control and reward-based decision making; previous studies of adolescent cannabis users have demonstrated subtle deficits in problem-solving, attention, memory and executive functions. 

“In adult cannabis users, decreased activation of the OFC has been associated with faulty decision-making, suggesting that a reduced ability to weigh the pros and costs of one’s actions might render certain individuals more prone to drug problems,” Professor Lubman said. 

“These results have important implications for understanding neurobiological predictors of cannabis use, but further research is still needed to understand their relationships with heavier patterns of use in adulthood as well as later abuse of other substances.” 

This research has been published online in Biological Psychiatry, the official journal of the Society of Biological Psychiatry. 

Source: Monash University [December 13, 2011]

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How We Decide

Until now, most psychology and neural imaging research have focused on how humans learn behavior through trial and error. 

However, Carnegie Mellon University neuroscientists Matthew M. Walsh and John R. Anderson have found that this view is incomplete. 

In their study published in the Proceedings of the National Academy of Sciences (PNAS), Walsh and Anderson show how the brain uses both instruction and experience to select actions. 

This identification of separate neural systems that control behavior also suggests that damage to one may not impair the other. 

"With most decisions that we make, we have access to both experience and instruction sources of information, so it is overly simplistic to just consider one," said Walsh, a doctoral student in the Department of Psychology within CMU's Dietrich College of Humanities and Social Sciences. 

"By tapping different neural learning systems, we can facilitate learning in patient populations. For example, Parkinson's disease is associated with a loss of dopamine and an impaired ability to learn from experience. Consequently, Parkinson's patients may more readily learn from instruction than experience." 

For the study, Walsh and Anderson used electroencephalography (EEG) to measure participants' neural activity during experiments designed to explore how instruction influences trial and error learning.   

The participants were shown two symbols that were assigned different reward values. Their goal was to maximize their reward by selecting the symbol that was more likely to be rewarded within each pair. 

One group received a description of the rewards before choosing, while the other group only received feedback about whether their choices were rewarded. 

The results showed that participants who did not receive instruction gradually learned from experience. Participants who did receive instruction performed perfectly from the beginning. 

Walsh and Anderson focused their analyses on the feedback-related negativity (FRN), a neural signal of reward learning. 

In striking contrast to their behavior, the FRN only developed once participants experienced outcomes in both conditions of the experiment. Thus, while instruction governed behavior, experience controlled the FRN. 

"Little research to this point has looked at how instruction engages behavior," said Walsh. 

"Our work shows that different systems in the brain control behavior, and that one system may learn from experience while the other controls responses." 

Anderson, the R.K. Mellon University Professor of Psychology and Computer Science, has spent the past three decades combining cognitive psychology research with computer science to understand how the brain works, how people learn and how computer-based instructional systems can be used as educational aids. 

For his trailblazing contributions, he received the 2011 Benjamin Franklin Medal in Computer and Cognitive Science. 

"These results highlight a striking dissociation between behavioral and neural responses. While instruction may immediately control behavior, certain neural responses must be learned from experience. Although some theories anticipate such a dissociation, this is the most direct evidence to date," said Anderson. 

Source: Carnegie Mellon University [December 12, 2011]

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The brain on trial

How should insights about the brain affect the course of a criminal trial, from the arguments in a courtroom to the issuing of a sentence? 

This was the topic of the Fred Kavli Public Symposium, held recently at the Society for Neuroscience's "Neuroscience 2011." Titled "The Brain on Trial: Neuroscience and the Law," the symposium looked at how advances in neuroscience are both challenging and assisting the judicial system. To explore this further, The Kavli Foundation brought together three experts to discuss the subject. Joining the dialogue: 

• Alan Leshner, symposium chair; chief executive officer of the American Association for the Advancement of Science and former head of the National Institute of Drug Abuse; 

• Martha Farah, director of the Center for Neuroscience and Society, University of Pennsylvania; 

• Jay Giedd, MD, an expert in adolescent brain development at the National Institute of Mental Health and chief of NIMH's Unit on Brain Imaging in the Child Psychiatry Branch. 

Together they examined the role neuroscience should have in determining legal policies and judgments, discussed innovative brain-based treatments for certain pathological behavior, and raised concerns about the use and misuse of scientific evidence. "The mere fact that brain processes give rise to the behavior isn't enough to excuse it," said Farah. "But the law does recognize some psychological conditions that diminish responsibility, and if neuroscience knows something about the neural processes underlying these conditions, it can aid in their diagnoses." 

Among the critical issues: how new insights about brain maturity should be used when assessing teenage crimes. "There currently is debate about whether adolescent brain maturity should be considered in sentencing for a crime or help determine what would be the proper deterrent for future adverse behavior," explained Giedd. "...What's difficult is applying this to individuals, as there are so many exceptions to the rule - there are many mature teens, and likewise immature people in their twenties and thirties. So the real challenge is going from group averages to individual prediction or characterization." 

Another issue is how a deeper understanding of addiction should affect sentencing. Said Leshner, "By combining the health approach to the criminal justice approach, I think you have a better chance of having effective and acceptable public policy. If you don't deal with the illness or the brain part of drug addiction, you have much less chance of actually reducing the behavior you don't like, whether it's drug using or committing crimes." 

For the complete discussion with Alan Leshner, Martha Farah and Jay Giedd, visit: http://www.kavlifoundation.org/science-spotlights/neuroscience-brain-trial 

Source: The Kavli Foundation [December 12, 2011]

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What do animals 'know'? More than you may think

Rats use their knowledge to make decisions when faced with ambiguous situations, UCLA psychologists report.

A rat finds a reward in an ambiguous situation [Credit: Aaron Blaisdell/UCLA Psychology]

"Rats often make judgments and behave as if they're rational creatures," said UCLA associate professor of psychology Aaron Blaisdell, a member of UCLA's Brain Research Institute and senior author of a new study published in the December issue of the journal Psychonomic Bulletin and Review.

"To make a decision in the face of uncertainty, rats call on prior history and reasoning," Blaisdell said. "They apply what they know to a situation where they are uncertain. The rats are not necessarily thinking like little humans, but they have learned through experience. A lot of animal behavior seems to be rational. Their behavior follows logical inferences."


Blaisdell, an expert in animal cognition (he avoids the phrase "animal intelligence"), and Cynthia Fast, the study's lead author and a UCLA graduate student in psychology, report on a series of experiments in which 74 female rats were rewarded with a sugar solution — which rats like about as much as teenagers like soda, Blaisdell said — for pressing a lever under certain conditions but not under others, which they learned to differentiate. 

The rats, none of which were harmed, first learned to expect the sugar reward if they pressed a lever when they saw one of two lights illuminated in their enclosure but not when they saw both lights on. After learning this pattern in 90 days, the rats were shown only one illuminated light while the other light was covered. In this case, the rats searched less for the sugar solution, as if both lights were on. This indicated, Blaisdell said, that the rats imagined the other light to be on, even though they could not see it. 

"Their behavior is consistent with their having an image of the light being on," Blaisdell said. "When we didn't cover the light, they knew what decision to make. They have the ability to hold an image of something that is not there and make a decision based on that." 

"Their prior learning influenced how they perceived this ambiguity," Fast said. "The rats responded less in this condition than they would if there was just a single light but more than they would if both lights were on. It would be like your driving on your commute and approaching an intersection where you know there is a traffic light but you can't see it because a tree branch or a bus in front of you is blocking your view. You approach slowly until you're able to see if the light is red or green. The rats seem to be doing the same thing. It's as if they reason, 'Hmm, I can't see the light on the right; maybe it's on,' and they press the lever less than they would if there were just a single light on."

The research was federally funded by the National Science Foundation.

In another experiment, rats were given the reward only if they pressed a lever when both lights were on, but not when either light was on alone — a pattern they learned much more quickly (in only 30 days). Then the psychologists covered one of the lights to study how the rats would respond. 

What was surprising, they said, was that covering the light in this case did not seem to have any impact on the rats' decision to respond. They continued to behave as if they were certain that the covered light was not on.

 To find out why, the researchers conducted a follow-up experiment in which the rats were again given the reward for pressing the lever when both lights were on (but not when only one was on), and they were also given the reward if they pressed the lever when they heard a tone or a clicking sound — but not the tone and clicking sound simultaneously. Other rats were given the reward only if the tone and clicking sound occurred together, not separately.

"The rats are capable of learning that too," Fast said. "They learn to differentiate among these different lights and different auditory cues and can tell them all apart." 

"It takes them a long time," Blaisdell said.

The rats were more sensitive to ambiguity when the uncertainty followed the more challenging training involving both the lights and the auditory cues, even in the condition that failed to make a difference previously, Fast and Blaisdell report.

"The difficulty of the task the rats are engaged in affects how they deal with uncertainty," Blaisdell said. "When the task is more difficult, they address it in a more sophisticated fashion. As far as I know, that has not been shown with any animal before."

 Little is known about how human imagination works, but an understanding of how widespread imagination is across the animal kingdom can shed light on the origins of imagination,
Blaisdell said. 

The aging brain 

The ability to make decisions in ambiguous situations declines with age, Blaisdell and Fast noted.

"With aging, decision-making becomes more fragile, especially in the face of lack of information," Blaisdell said. 

Blaisdell is interested in learning the brain mechanisms involved in decision-making and perhaps applying this research to human cognition and neural changes that occur with aging or with degenerative diseases. He also hopes to gain new insights into how we learn.

"There is still so much we don't know about learning," he said. "The more we can understand about how the brain supports cognition, the more we will be able to look for where cognition is going wrong when the brain malfunctions." 

Author: Stuart Wolpert | Source: University of California Los Angeles [December 08, 2011]

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Psychology researcher finds that power does go to our heads

Power -- defined as the ability to influence others -- makes people think differently. For North Americans, a feeling of power leads to thinking in a focused and analytical way, which may be beneficial when pursuing personal goals. 

"What's most interesting about this study is the idea that thinking is flexible, not rigid or innately pre-programmed. We are able to attune our style of thinking to the needs of the situation," explains Li-Jun Ji, the study's co-author and a social psychologist who studies the relationships between culture and thinking. "However, the specific ways we might attune our thinking seems to depend on our cultural background." 

For most people, being in a position of power or influence means that you want to influence others and achieve your own goals. In North America, these goals tend to be self-defined and independent from the wider social context. As a result, thinking -- focusing on one's own goal and how to achieve it without being distracted by the surrounding context -- can be advantageous. 

Dr. Ji also found that North American individuals with high socioeconomic status (SES) displayed more analytical thinking than low SES individuals. She believes that this may be because higher SES increases people's feelings of agency, a precursor to power. 

In order to induce feelings of power, the researchers asked study participants to recollect occasions in their lives when they had influenced others. The kind of memories the participants recalled included making a shy roommate more outgoing, influencing people to buy products as part of a fundraiser, and leading a struggling soccer team to victory. 

The participants were then asked to complete a number of different tasks designed to assess whether they were thinking more analytically or more holistically. Analytical thinking is characterized by processing a focal object and its features independently from its surrounding context (for example, using adjectives to describe a ball as 'red' or 'round'). Holistic thinking involves a focus on contextual information and the relationships between objects (for example, using verbs like 'kick' or 'play' to highlight the connection between the ball and its environment).  

This research was published in the Personality and Social Psychology Bulletin. 

Source: Queen's University [December 06, 2011]

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Which way you lean — physically — affects your decision-making

We’re not always aware of how we are making a decision. Unconscious feelings or perceptions may influence us. Another important source of information—even if we’re unaware of it—is the body itself. 

“Decision making, like other cognitive processes, is an integration of multiple sources of information—memory, visual imagery, and bodily information, like posture,” says Anita Eerland, a psychologist at Erasmus University Rotterdam in the Netherlands. In a new study, Eerland and colleagues Tulio Guadalupe and Rolf Zwaan found that surreptitiously manipulating the tilt of the body influences people’s estimates of quantities, such as sizes, numbers, or percentages. The findings will appear in an upcoming issue of Psychological Science, a journal published by the Association for Psychological Science. 

When we think about numbers, we mentally represent smaller numbers to the left and larger numbers to the right. The researchers surmised that leaning one way or the other—even imperceptibly—might therefore nudge people to estimate lower or higher. To test this hypothesis, study participants—33 undergraduates—stood on a Wii Balance Board that imperceptibly manipulated their posture to tilt left or right or stay upright while they answered estimation questions appearing on a screen. The participants were told they probably didn’t know the answers and therefore would have to estimate; they were also instructed to stand upright throughout the trials. A representation on the screen, below the question, of the person’s posture showed it to be upright even when it was not.  The participants answered the questions one by one verbally. 

In the first experiment, the estimations were of different kinds of quantities—e.g., the height of the Eiffel Tower or percentage of alcohol in whiskey. In the second, the quantities were all of the same kind—How many grandchildren does Queen Beatrix of the Netherlands have? How many Number 1 hits did Michael Jackson have in the Netherlands? The answers were all between 1 and 10. 

As expected, participants gave smaller estimations when leaning left than when either leaning right or standing upright. There was no difference in their estimates between right-leaning and upright postures. 

The researchers point out that body posture won’t make you answer incorrectly if you know the answer. “Your body posture may nudge your estimates in a particular direction,” says Zwaan. Adds Eerland: “Posture doesn’t overwrite knowledge.” 

Still, says Zwaan, we should not mistake our cognitive processes as perfectly and consciously rational. “Decision-making is not a pristine process.  All sources of information creep into it, and we are just beginning to explore the role of the body in this.” 

Source: Association for Psychological Science [November 07, 2011]

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