Science reveals the power of a handshake

ScienceDaily (Oct. 19, 2012) — New neuroscience research is confirming an old adage about the power of a handshake: strangers do form a better impression of those who proffer their hand in greeting.

A firm, friendly handshake has long been recommended in the business world as a way to make a good first impression, and the greeting is thought to date to ancient times as a way of showing a stranger you had no weapons. Now, a paper published online and for the December print issue of the Journal of Cognitive Neuroscience on a study of the neural correlates of a handshake is giving insight into just how important the practice is to the evaluations we make of subsequent social interactions.

The study was led by Beckman Institute researcher Florin Dolcos and Department of Psychology postdoctoral research associate Sanda Dolcos. They found, as they wrote, that "a handshake preceding social interaction enhanced the positive impact of approach and diminished the negative impact of avoidance behavior on the evaluation of social interaction."

Their results, for the first time, give a scientific underpinning to long-held beliefs about the important role a handshake plays in social or business interactions. Sanda Dolcos said their findings have obvious implications for those who want to make a good impression.

"I would tell them to be aware of the power of a handshake," she said. "We found that it not only increases the positive effect toward a favorable interaction, but it also diminishes the impact of a negative impression. Many of our social interactions may go wrong for a reason or another, and a simple handshake preceding them can give us a boost and attenuate the negative impact of possible misunderstandings."

The study focused experimentally on approach and avoidance behaviors in social interactions. Functional magnetic resonance imaging (fMRI), skin conductance, and behavioral responses were collected from18 male and female volunteers who watched and rated animated videos of non-verbal guest-host interactions in a business setting. Analysis of the fMRI data focused on brain areas from the social cognition network.

The results showed "increased sensitivity to approach than to avoidance behavior in amygdala and superior temporal sulcus, which were linked to a positive evaluation of approach behavior and a positive impact of handshake." In addition, the researchers wrote, the "nucleus accumbens, which is a reward processing region, showed greater activity for Handshake than for No-handshake conditions" -- thus demonstrating a link to "the positive effect of handshake on social evaluation."

"The regions of the social cognition network are commonly engaged when people are assessing the intentions of others," Florin Dolcos said. "They had been identified before and people who have difficulty in interactions, like people with autism, have reduced response in this region.

"But, unlike previous studies, we simulated approach and avoidance behaviors using animated characters that displayed obvious interest or indifference for further interactions. This is the first time that such a manipulation was used in a relevant context."

The videos the participants watched included animated human figures in a setting that indicated a business-type interaction. The figures included a host and a guest encountering each other for the first time. Florin Dolcos said using animated videos with human figures interacting in a defined social context was a big step forward in this type of research.

"Previous research investigating social interactions has used static instead of dynamic social stimuli, or focused only on faces," he said. "However, in everyday life people are typically involved in dynamic interactions with others in a defined social context. I think that is what sets this study apart."

Sanda Dolcos summed up the results: "Overall, our study not only replicated previous reports that identify activity in regions of the social cognition network, but also provided insight into the contribution of these regions into evaluating approach and avoidance social interactions, and grant neuroscientific support for the power of a handshake."

Florin Dolcos added that it's not just any handshake that leads to positive feelings, but a particular way of shaking hands, such as a firm, confident, yet friendly handshake, as is often promoted as good business practice.

"In a business setting this is what people are expecting, and those who know these things use them," he said. "Not a very long time ago you could get a loan based on a handshake. So it conveys something very important, very basic. Yet the science underlying this is so far behind. We knew these things intuitively but now we also have the scientific support."

Florin Dolcos is a member of Beckman's Cognitive Neuroscience group, heads the Dolcos Lab for Affective, Cognitive, and Clinical Neuroscience, and is Assistant Professor in the Department of Psychology.

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The above story is reprinted from materials provided by Beckman Institute for Advanced Science and Technology.

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Journal Reference:

Sanda Dolcos, Keen Sung, Jennifer J. Argo, Sophie Flor-Henry, Florin Dolcos. The Power of a Handshake: Neural Correlates of Evaluative Judgments in Observed Social Interactions. Journal of Cognitive Neuroscience, 2012; : 1 DOI: 10.1162/jocn_a_00295

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New fruit fly model of epilepsy reveals mechanisms behind fever-induced seizures

ScienceDaily (Oct. 17, 2012) — UC Irvine and Brown University researchers have created a new fruit fly model of inherited epilepsy that's providing insights into the mechanisms underlying temperature-dependent seizures while establishing a platform from which to develop therapies for these disorders.

In the Oct. 10 issue of The Journal of Neuroscience, Diane O'Dowd of UCI, Robert Reenan of Brown and colleagues report their method for placing a gene mutation that causes human fever-induced seizures into drosophila fruit flies. As a result, the mutant flies experience heat-induced seizures.

This represents the first time a human genetic disease mutation has been "knocked in" to the equivalent location in the fruit fly genome. The drosophila knock-in model provides a rapid and low-cost basis for defining the neural mechanisms contributing to inherited seizure disorders.

"We can also use this genetic model of human epilepsy in fruit flies to look for new treatments for the disease," said O'Dowd, professor and chair of developmental & cell biology at UCI.

Fever-induced, or febrile, seizures are most commonly seen in children. Only about one in 100 children with febrile seizures develops epilepsy, and most outgrow them by age 5. In contrast, individuals who have the inherited disorder -- termed GEFS+ -- have febrile seizures that persist beyond childhood and also often develop seizures in the absence of fever.

Reenan, a biology professor at Brown, and Brown undergraduate Jeff Gilligan used a genetic-exchange research method called "homologous recombination" to insert a mutation into the gene in fruit flies that's a direct parallel of the GEFS+ mutation in the human SCN1A sodium channel gene that causes febrile seizures in people.

When placed in tubes that were put in warm water, most of the mutant fruit flies began to experience seizures within 20 to 30 seconds. They would fall over, and their wings would flap and their legs twitch for about two minutes while the flies were kept at a high temperature. The researchers found that seizure susceptibility was dose-dependent: Ninety-five percent of the flies with two copies of the mutant gene had seizures, as opposed to 60 percent of those with just one copy. Unaltered control flies did not have temperature-dependent seizures.

To determine the neurological causes of the seizures, O'Dowd, her postdoctoral fellow and lead study author Lei Sun, and UCI colleagues examined neurons in the brains of both mutant and control flies to monitor activity and see how they behaved as the brains were heated. In the mutant flies, they discovered flaws in the functioning of sodium channels.

"What happens is the mutant channels don't open and close properly," O'Dowd said. "This effect is amplified at high temperature, and this changes the ability of neurons to generate the appropriate electrical signals, leading to hyperactivity in the brain circuits."

"With this knowledge, the next step is to use this model to look for drugs that might reduce or eliminate heat-induced seizures," she added.

In addition to providing insight into the neurology of febrile seizures, the study establishes a new fruit fly model as a viable genetic platform for the study of epilepsy and validates the use of homologous recombination in flies to explore mechanisms underlying other genetically linked diseases.

Ryan Schutte and Vivian Nguyen of UCI and Cynthia Staber of Brown also contributed to the study, which was funded by the National Institutes of Health, Howard Hughes Medical Institute and the Ellison Medical Foundation.

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Journal Reference:

L. Sun, J. Gilligan, C. Staber, R. J. Schutte, V. Nguyen, D. K. O'Dowd, R. Reenan. A Knock-In Model of Human Epilepsy in Drosophila Reveals a Novel Cellular Mechanism Associated with Heat-Induced Seizure. Journal of Neuroscience, 2012; 32 (41): 14145 DOI: 10.1523/JNEUROSCI.2932-12.2012

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