Posts tagged psychology
Articles and news from the latest research reports.
Limits on Brain’s Ability to Perceive Multifeatured Objects
New research sheds light on how the brain encodes objects with multiple features, a fundamental task for the perceptual system. The study, published in Psychological Science, a journal of the Association for Psychological Science, suggests that we have limited ability to perceive mixed color-shape associations among objects that exist in several locations.
Research suggests that neurons that encode a certain feature — shape or color, for example — fire in synchrony with neurons that encode other features of the same object. Psychological scientists Liat Goldfarb of the University of Haifa and Anne Treisman of Princeton University hypothesized that if this neural-synchrony explanation were true, then synchrony would be impossible in situations in which the same features are paired differently in different objects.
Say, for example, a person sees a string of letters, “XOOX,” and the letters are printed in alternating colors, red and green. Both letter shape and letter color need to be encoded, but the associations between letter shape and letter color are mixed (i.e., the first X is red, while the second X is green), which should make neural synchrony impossible.
“The perceptual system can either know how many Xs there are or how many reds there are, but it cannot know both at the same time,” Goldfarb and Treisman explain.
The researchers investigated their hypothesis in two experiments, in which they presented participants with strings of green and red Xs and Os and asked them to compare the number of Xs with the number of red letters (i.e., more Xs, more reds, or the same).
Participants’ responses to unique color-shape associations were significantly faster and more accurate than were their responses to displays with mixed color-shape associations.
The results show that relevant color and shape dimensions could be synchronized when the pairings between color and shape were unique, but not when the pairings were mixed.
These findings demonstrate a new behavioral principle that governs object representation. When shapes are repeated in several locations and have mixed color-shape associations, they are hard to perceive.
This research expands on Anne Treisman’s groundbreaking research on feature integration in visual perception, which shows that humans can encode characteristics such as color, form, and orientation, even in the absence of spatial attention.
Treisman is one of 12 scientists who received the National Medal of Science at the White House on February 1, 2013. The National Medal of Science, along with the National Medal of Technology and Innovation, is the highest honor that the US government grants to scientists, engineers, and inventors.
Bilingual babies know their grammar by 7 months
Babies as young as seven months can distinguish between, and begin to learn, two languages with vastly different grammatical structures, according to new research from the University of British Columbia and Université Paris Descartes.
Published today in the journal Nature Communications and presented at the 2013 Annual Meeting of the American Association for the Advancement of Science (AAAS) in Boston, the study shows that infants in bilingual environments use pitch and duration cues to discriminate between languages – such as English and Japanese – with opposite word orders.
In English, a function word comes before a content word (the dog, his hat, with friends, for example) and the duration of the content word is longer, while in Japanese or Hindi, the order is reversed, and the pitch of the content word higher.
"By as early as seven months, babies are sensitive to these differences and use these as cues to tell the languages apart," says UBC psychologist Janet Werker, co-author of the study.
Previous research by Werker and Judit Gervain, a linguist at the Université Paris Descartes and co-author of the new study, showed that babies use frequency of words in speech to discern their significance.
"For example, in English the words ‘the’ and ‘with’ come up a lot more frequently than other words – they’re essentially learning by counting," says Gervain. "But babies growing up bilingual need more than that, so they develop new strategies that monolingual babies don’t necessarily need to use."
"If you speak two languages at home, don’t be afraid, it’s not a zero-sum game," says Werker. "Your baby is very equipped to keep these languages separate and they do so in remarkable ways."
Gene thought to be linked to Alzheimer’s is marker for only mild impairment
Defying the widely held belief that a specific gene is the biggest risk factor for Alzheimer’s disease, two Cornell developmental psychologists and their colleagues report that people with that gene are more likely to develop mild cognitive impairment — but not Alzheimer’s.
The study suggests that older adults with healthy brain function can get genetic tests to predict increased risk of future mild cognitive impairment. However, once they are impaired cognitively, the tests won’t predict their likelihood of developing Alzheimer’s.
"Right now, genetic tests are used in exactly the opposite way. That is, healthy people don’t get the tests to predict their risk of mild cognitive impairment, but impaired people get them to predict their risk of Alzheimer’s disease," said Charles Brainerd, professor of human development and the study’s lead co-author with Valerie Reyna, professor of human development. "So, impaired people think that tests will tell them if they are at increased risk of Alzheimer’s, which they won’t. And healthy people think that tests won’t tell them whether they are at increased risk of cognitive impairment, which they will."
The researchers describe their findings in the January issue of Neuropsychology (27:1).
The work builds on previous research by Brainerd and associates that suggested the ε4 allele of the APOE genotype increases the risk of mild cognitive impairment as well as Alzheimer’s.
The researchers analyzed data from the only nationally representative dataset of its kind, the National Institute on Aging’s Aging, Demographics and Memory Study. They looked at data from 418 people over age 70 to see if those who carried the allele were more likely to develop mild cognitive impairment compared with those who did not have the allele. They also looked at whether ε4 carriers with mild cognitive impairment were more likely to develop Alzheimer’s disease compared with non-carriers with mild cognitive impairment.
They found that healthy ε4 carriers were nearly three times — 58 percent — more likely to develop mild cognitive impairment compared with non-carriers. However, ε4 carriers with mild cognitive impairment developed Alzheimer’s at the same rate as non-carriers.
Early music lessons boost brain development
If you started piano lessons in grade one, or played the recorder in kindergarten, thank your parents and teachers. Those lessons you dreaded – or loved – helped develop your brain. The younger you started music lessons, the stronger the connections in your brain.
A study published last month in the Journal of Neuroscience suggests that musical training before the age of seven has a significant effect on the development of the brain, showing that those who began early had stronger connections between motor regions – the parts of the brain that help you plan and carry out movements.
This research was carried out by students in the laboratory of Concordia University psychology professor Virginia Penhune, and in collaboration with Robert J. Zatorre, a researcher at the Montreal Neurological Institute and Hospital at McGill University.
The study provides strong evidence that the years between ages six and eight are a “sensitive period” when musical training interacts with normal brain development to produce long-lasting changes in motor abilities and brain structure. “Learning to play an instrument requires coordination between hands and with visual or auditory stimuli,” says Penhune. “Practicing an instrument before age seven likely boosts the normal maturation of connections between motor and sensory regions of the brain, creating a framework upon which ongoing training can build.”
My gray matter might be waning. Then again, it might not be. But I swear that I can feel memories — as I’m making them — slide off a neuron and into a tangle of plaque. I steel myself for those moments to come when I won’t remember what just went into my head.
I’m not losing track of my car keys, which is pretty standard in aging minds. Nor have I ever forgotten to turn off the oven after use, common in menopausal women. I can always find my car in the parking lot, although lots of “normal” folk can’t.
Rather, I suddenly can’t remember the name of someone with whom I’ve worked for years. I cover by saying “sir” or “madam” like the Southerner I am, even though I live in Vermont and grown people here don’t use such terms. Better to think I’m quirky than losing my faculties. Sometimes I’ll send myself an e-mail to-do reminder and then, seconds later, find myself thrilled to see a new entry pop into my inbox. Oops, it’s from me. Worse yet, a massage therapist kicked me out of her practice for missing three appointments. I didn’t recall making any of them. There must another Nancy.
Am I losing track of me?
Waiting for the Forgetting to Begin by Nancy Stearns Bercaw
This Is Your Brain On Movies: Neuroscientists Weigh In On The Brain Science of Cinema
In movies, we explore landscapes far removed from our day-to-day lives. Whether experiencing the fantastical adventures of Star Wars or the dramatic throes of The English Patient, movies demand that our brains engage in a complex firing of neurons and cognitive processes. We enter into manipulated worlds where musical scores enhance feeling; where cinematography clues us into details we’d normally gloss over; where, like omniscient beings, we voyeuristically peek into others’ lives and minds; and where we can travel from Marrakech to Mars without ever having left our seat. Movies reflect reality, yet are anything but.
“Movies are highly complex, multidimensional stimuli,” said Uri Hasson, a neuroscientist and psychologist at Princeton University. “Some areas of the brain analyze sound bites, some analyze word context, some the sentence content, music, emotional aspect, color or motion.” Just as many people must come together to work on different elements of a movie’s script, score, visuals or costumes, he explained, so many areas of the brain must also be engaged in processing those disparate elements.
The relatively new field of neurocinematic studies seeks to untangle our neurological experience of film and, in doing so, learn not only the mechanisms behind movie watching but also how movies might teach us more about ourselves.
Secrets of lasting love are hidden inside the brain
Researchers have found that they can spot the signs of a true romance in people embarking on a new relationship by looking at how much their brains light up when they think about their new partner.
The scientists detected distinctive patterns of electrical activity in the brains of volunteers who believed they had recently fallen in love, and found that they could use the scans to predict whether a couple would stay together.
The findings could end the uncertainty of courting by revealing whether a couple are likely to have a long relationship or whether their feelings will fizzle out.
The scans showed that even if someone believed they had fallen in love, the activity of their neurons could suggest whether their feelings were strong enough for them to be with the other person three years later.
Prof Arthur Aron, a social psychologist at Stony Brook University in Long Island, New York, said: “All of those involved in the study felt very intensely in love with their partner and this was reflected in their scans, but there were some subtle indicators that showed how stable those feeling were.
“If that strong feeling was combined with signs that they could regulate emotions, to see the partner positively and deal with conflict, then it seems to be really productive in staying with the person.” The psychologists, whose research was published in the journal Neuroscience Letters, found a number of key parts of the brain were involved.
Using magnetic resonance imaging, the scientists scanned 12 volunteers, seven of whom were women, who had fallen passionately in love and had been with their partner for about a year. As they were scanned, each was shown a picture of their partner and asked to think of memories of them. The participants were also asked to think about and look at pictures of an acquaintance with whom they had no romantic attachment. Three years later, the researchers compared the scans with the outcome of each relationship. Half the relationships had lasted.
The scientists found that the scans of those who were still in relationships had heightened levels of activity, when thinking of their partner, in an area of the brain that produces emotional responses to visual beauty, known as the caudate tail.
These people also had lower levels of activity in the pleasure centres of the brain that relate to addiction and seeking rewards. The scientists say deactivation in this area has been linked to satiety and satisfaction.
Another part of the brain, known as the medial orbitofrontal cortex, was also less active, which the scientists say made those people less critical and judgmental about their partners.
Aron said the research could have a practical application in helping people having relationship problems.
He said: “The brain is so complex that we are still quite a way from being able to very precisely pick out these qualities, but it does allow us to get at what is really going on inside someone aside from what they tell us.
“We may eventually get to a point where we can recognise things that the person doesn’t recognise themselves and we can say that they are not as intensely attached to a person as they think they are.”
Prof Aron added: “This probably facilitates handling the conflicts that inevitably arise when you spend a lot of time with someone. It plays a big part in keeping people together and staying satisfied.”
A fourth area known to modulate mood and self-esteem was less active in those who stayed together, something the scientists think may be linked to people forming stable and intimate bonds.
The psychologists also found they could spot signs of how happy a couple who stayed together would be in the scans taken three years earlier.
Xiaomeng Xu, the lead author of the study at Brown University in Rhode Island, said: “Factors present early in the early stages of romantic love seem to play a major role in the development and longevity of the relationship.
“Our data provides preliminary evidence that neural responses in the early stages of romantic love can predict relationship stability and quality up to 40 months later.
“The brain regions involved suggest that reward functions may be predictive for relationship stability.”
Two years ago, researcher Josef Bless was listening to music on his phone when he suddenly had an idea.
"I noticed that the sounds of the different instruments were distributed differently between the ears, and it struck me that this was very similar to the tests we routinely use in our laboratory to measure brain function. In dichotic listening, each ear is presented with a different syllable at the same time (one to the left and one to the right ear) and the listener has to say which syllable seems clearest. The test indicates which side of the brain is most active during language processing," Bless explains.
Josef Bless is working on a PhD in psychology at the University of Bergen. He is a member of the Bergen fMRI Group, an interdisciplinary research group headed by Professor Kenneth Hugdahl, who has received a European Research Council (ERC) Advanced Grant for his brain research.
The iPhone app for dichotic listening is called iDichotic and was launched on the App Store in 2011, where it can be downloaded for free. Some one year later, more than 1,000 people have downloaded the app, and roughly half have sent their test results to the researchers’ database.
The researchers analysed the first 167 results they received and compared them with the results of 76 individuals tested in laboratories in Norway and Australia. The results have been published in the journal Frontiers in Psychology.
"We found that the results from the app were as reliable as those of the controlled laboratory tests. This means that smartphones can be used as a tool for psychological testing, opening up a wealth of exciting new possibilities," says Bless.
"The app makes it possible to gather large volumes of data easily and inexpensively. I think we will see more and more psychological tests coming to smartphones," he adds.
The researchers have also developed a special version of iDichotic for patients with schizophrenia who suffer from auditory hallucinations (i.e. hear “voices”). The app helps in training patients to improve their focus, so that when they hear voices, they are better able to shut them out.
"Using a mobile app, patients can be tested and receive training at home, instead of having to come to our laboratory," says Bless.
The app iDichotic has been developed in collaboration with Professor Kenneth Hugdahl, Doctor René Westerhausen, and Magne Gudmundsen.
Fear factor: Study shows brain’s response to scary stimuli
Driving through his hometown, a war veteran with post-traumatic stress disorder may see roadside debris and feel afraid, believing it to be a bomb. He’s ignoring his safe, familiar surroundings and only focusing on the debris; yet, when it comes to the visual cortex, a recent study at the University of Florida suggests this is completely normal.
The findings, published last month in the Journal of Neuroscience, show that even people who don’t have anxiety disorders respond visually at the sight of something scary while ignoring signs that indicate safety. This contradicts a common belief that only people with anxiety disorders have difficulty processing comforting visual stimuli, or safety cues, said Andreas Keil, a professor of psychology in UF’s College of Liberal Arts and Sciences.
“We’ve established that, in terms of visual responding, it’s not a disorder to not respond to a safety cue,” Keil said. “We all do that. So now we can study at what stage in the processing stream, with given patients, is the problem occurring.”
Co-authors Keil and Vladimir Miskovic, both members of the UF Center for the Study of Emotion and Attention, examined the effect of competing danger and safety cues within the visual cortex. The study results could help distinguish between normal and abnormal processes within the visual cortex and identify what parts of the brain are targets for the treatment of anxiety disorders.
“You’d think the visual cortex would just faithfully code for visual information,” said Shmuel Lissek, an assistant professor of psychology at the University of Minnesota not involved in the study. “This kind of work is testing the idea that activations in the visual cortex are actually different if the stimulus has an emotional value than if it doesn’t.”
(Source: news.ufl.edu)
Turning repulsive feelings into desires
Hunger, thirst, stress and drugs can create a change in the brain that transforms a repulsive feeling into a strong positive “wanting,” a new University of Michigan study indicates.
The research used salt appetite to show how powerful natural mechanisms of brain desires can instantly transform a cue that always predicted a repulsive Dead Sea Salt solution into an eagerly wanted beacon or motivational magnet.
Mike Robinson, a research fellow in the U-M Department of Psychology and the study’s lead author, said the findings help explain how related brain activations in people could cause them to avidly want something that has been always disliked.
This instant transformation of motivation, he said, lies in the ability of events to activate particular brain circuitry—a structure called the nucleus accumbens, which sits near the base of the front of the brain and is also activated by addictive drugs.
Cues for rewards often trigger intense motivation. The smell of food can make a person suddenly feel hungry when this wasn’t the case earlier. Drug cues may prompt relapse in addicts trying to quit. In some cases, desires may be triggered even for a relatively unpleasant event.
Researchers studied how rats responded to metal objects that represented either pleasant sugar or disgustingly intense Dead Sea saltiness. The rats quickly learned to jump on and nibble the sweetness cue, but turned away from and avoided the saltiness cue.
But one day the rats suddenly woke up in a new state of sodium appetite induced by drugs given the night before. On their first re-encounter with the saltiness cue in the new appetite state, their brain systems became activated and the rats instantly jumped on and nibbled the saltiness cue as though it were the sugar cue.
"The cue becomes avidly ‘wanted’ despite knowledge the salt always tasted disgusting," Robinson said.
The sudden brain changes help explain how an event, such as taking an addictive drug, could become “wanted” despite a person’s knowledge of the negative and unpleasant consequences of the drug.
"Our findings highlight what it means to say that drugs hijack our natural reward system," said Robinson, who authored the new study with Kent Berridge, James Olds Collegiate Professor of Psychology and Neuroscience.