Odor Matching: The Scent Of Internet Dating

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ScienceDaily (Apr. 12, 2009) — Dating websites will soon be able to compare partners in terms of whether the personal body odour of the other party will be pleasant to them. This has a very serious biological background.

If the start-up company Basisnote get their way, we will soon not only be able to match looks and interests in the profile of a potential partner with our own preferences. Now even the individual smell of the other party can be recorded in the profile and then checked to see if it will be pleasant for us. Even before going on the first date.
“If everything fits, you have the same interests, lots to talk about, but you can’t stand their smell, then a love affair doesn’t stand a chance,” explains biologist August Hämmerli. He makes the online smell profile possible with his company Basisnote. The start-up from Bern has worked together with ETH to develop a fast test to determine your own body odour and enter it as a code in a database. If the flirt partner has also entered their smell profile, you can find out within seconds whether you would like their smell.
All of this works by taking a saliva test, which can be carried out easily at home. It works with a chromatographic process, similar to a pregnancy test. The result: a simple digital code, which can be entered into an online profile. All of this takes no longer than twenty minutes. Hämmerli continues: “Obviously, smell is by no means the only factor in choosing a partner. However, our test makes it a measurable component.” The company is developing the test together with Mathias Wegner, head assistant at the Paul Schmidt-Hempel chair at the Institute for Integrative Biology. The test will appear on the market this year in cooperation with an online dating provider.
Immunity check through the nose
This all sounds like another gag for online dating platforms. Far from it. According to an explanatory model by evolutionary biologists, there is a valid explanation for why our nose is so important when it comes to choosing our partner. It is not without reason that we have to literally be able to “stand the smell” of our partner, if we are to find them likeable or even more. Our nose has sensitive receptors. They probe whether the other party has as few similar genes to us as possible. The more varied the gene pools are, the higher the chance for healthy, strong offspring.
It has been a well-known fact for a long time that mice check their potential mating partners by smelling them. The fact that humans do the same on a subconscious level was first proven in the nineties by biologist Claus Wedekind at University of Bern. He let female students smell T-shirts that had been worn by male test persons. The women had to indicate the smell that they found to be the most pleasant. It was shown that they consistently chose the men whose immune system was most different from their own.
How does this work? Basisnote founder August Hämmerli explains: “The genes of the MHC, the Major Histocompatibility Complex, carry the instructions for important building blocks of the immune system, the MHC proteins.” These bind fragments of foreign proteins, for example following an infection, and pass them on to the body’s own defence cells, which initiate a defence reaction. The more different MHC molecules someone has, the more different pathogens his body can defend against. In humans, there are more than one hundred variations of each of the nine most important MHC genes. The more varied the MHC, the better the immune systems of the offspring will be armed. Hämmerli: “The specific body odour is marked by the MHC combination. It is transmitted in the bodily fluids and transformed into the body’s very own smell on the skin.” The stronger the difference in immune system between the potential partner and yourself, the more pleasant you will find their smell.
Test instead of a T-shirt
According to Hämmerli, Basisnote is really just applying Wedekind’s T-shirt study to a standardised test system. August Hämmerli is so convinced of the success of his idea that he gave up his position as scientist at ETH to found the company. The Bern-born man coordinates the interface between the interested firms and the research work at the ETH laboratories. Co-founder Dominic Senn is an economist and political scientist. He also worked as a scientist at ETH up to the founding of the company, and is now responsible for the development of the business as CEO. Physicist Manuel Kaegi, who is just finishing his dissertation at the laboratory for safety analysis at ETH, looks after the IT implementation at Basisnote and interfaces with existing online dating platforms.
For two-and-a-half years, the three men have collected development funds and worked intensively on the details of the product. Now all technical issues have been resolved and it only remains to define the most user-friendly application. They are also preparing the first scientific publications on the subject.
The negotiations with online dating platforms are in their final phase. Hämmerli is happy to say that there has been great interest. He is reluctant to reveal which partner search site will soon be featuring smell as a dating component. This will have to wait until the autumn.
Setting up their own partner search site is out of the question. Their plans for the future are along other lines: “There are so many interesting areas. Once all of this is up and running, we want to have a look at the perfume sector,” Hämmerli reveals.
Adapted from materials provided by ETH Zurich.

Dogs And 2-year-olds Share A Limited Ability To Understand Adult Pointing Gestures

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ScienceDaily (Apr. 10, 2009) — Dogs and small children who share similar social environments appear to understand human gestures in comparable ways, according to Gabriella Lakatos from Eötvös University in Budapest, Hungary, and her team. Looking at how dogs and young children respond to adult pointing actions, Lakatos shows that 3-year-olds rely on the direction of the index finger to locate a hidden object, whereas 2-year-olds and dogs respond instead to the protruding body part, even if the index finger is pointing in the opposite direction.

It is widely accepted that in the course of domestication, dogs became predisposed to read human communication signals, including pointing, head turning and gazing. Furthermore, the social environment of human infants is often shared by pet dogs in the family, and therefore there are likely to be similarities in the social stimulation of both young children and dogs.
The authors carried out two studies in which they compared the performance of adult dogs and 2- and 3-year-old children - the period of human development during which children and dogs respond in similar ways. They investigated whether dogs and human children are able to generalize from familiar pointing gestures to unfamiliar ones and whether they understand the unfamiliar pointing actions as directional signals.
A total of fifteen dogs and thirteen 2-year-old and eleven 3-year-old children took part in the two studies. In the first study, the researchers used a combination of finger and elbow pointing gestures to help dogs locate hidden food and children a favorite toy. They found that dogs choose a direction for the reward on the basis of a body part that protrudes from the experimenter's silhouette, even when the index finger is pointing in a different direction. Like dogs, 2-year-olds did not understand the significance of the pointing index finger when it did not protrude from the silhouette. (In these cases, the elbow protruded in the opposite direction.) However, 3-year-olds responded successfully to all gestures.
In the second study, the researchers used unfamiliar pointing gestures with a combination of finger, leg and knee pointing. All children and the dogs understood the leg-pointing gestures but only 3-year-olds successfully responded to pointing with the knee.
The authors conclude that "protruding body parts provide the main cue for deducing directionality for 2-year-old children and dogs. The similar performance of these groups can be explained by parallels in their evolutionary history and their socialization in a human environment."
Journal reference:
Lakatos et al. A comparative approach to dogs’ (Canis familiaris) and human infants’ comprehension of various forms of pointing gestures. Animal Cognition, 2009; DOI: 10.1007/s10071-009-0221-4
Adapted from materials provided by Springer Science+Business Media, via AlphaGalileo.

Why We Have Difficulty Recognizing Faces In Photo Negatives

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ScienceDaily (Mar. 25, 2009) — Humans excel at recognizing faces, but how we do this has been an abiding mystery in neuroscience and psychology. In an effort to explain our success in this area, researchers are taking a closer look at how and why we fail.

A new study from MIT looks at a particularly striking instance of failure: our impaired ability to recognize faces in photographic negatives. The study, which appears in the Proceedings of the National Academy of Sciences this week, suggests that a large part of the answer might lie in the brain's reliance on a certain kind of image feature.
The work could potentially lead to computer vision systems, for settings as diverse as industrial quality control or object and face detection. On a different front, the results and methodologies could help researchers probe face-perception skills in children with autism, who are often reported to experience difficulties analyzing facial information.
Anyone who remembers the days before digital photography has probably noticed that it's much harder to identify people in photographic negatives than in normal photographs. "You have not taken away any information, but somehow these faces are much harder to recognize," says Pawan Sinha, an associate professor of brain and cognitive sciences and senior author of the PNAS study.
Sinha has previously studied light and dark relationships between different parts of the face, and found that in nearly every normal lighting condition, a person's eyes appear darker than the forehead and cheeks. He theorized that photo negatives are hard to recognize because they disrupt these very strong regularities around the eyes.
To test this idea, Sinha and his colleagues asked subjects to identify photographs of famous people in not only positive and negative images, but also in a third type of image in which the celebrities' eyes were restored to their original levels of luminance, while the rest of the photo remained in negative.
Subjects had a much easier time recognizing these "contrast chimera" images. According to Sinha, that's because the light/dark relationships between the eyes and surrounding areas are the same as they would be in a normal image.
Similar contrast relationships can be found in other parts of the face, primarily the mouth, but those relationships are not as consistent. "The relationships around the eyes seem to be particularly significant," says Sinha.
Other studies have shown that people with autism tend to focus on the mouths of people they are looking at, rather than the eyes, so the new findings could help explain why autistic people have such difficulty recognizing faces, says Sinha.
The findings also suggest that neuronal responses in the brain may be based on these relationships between different parts of the face. The team found that when they scanned the brains of people performing the recognition task, regions associated with facial processing (the fusiform face areas) were far more active when looking at the contrast chimeras than when looking at pure negatives.
Other authors of the paper are Sharon Gilad of the Weizmann Institute of Science in Israel and MIT postdoctoral associate Ming Meng, both of whom contributed equally to the work..
The research was funded by the Alfred P. Sloan Foundation and the Jim and Marilyn Simons Foundation.
Adapted from materials provided by Massachusetts Institute of Technology.

Contrary To Widely Held Beliefs, Romance Can Last In Long-term Relationships, Say Researchers

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ScienceDaily (Mar. 21, 2009) — Romance does not have to fizzle out in long-term relationships and progress into a companionship/friendship-type love, a new study has found. Romantic love can last a lifetime and lead to happier, healthier relationships.

"Many believe that romantic love is the same as passionate love," said lead researcher Bianca P. Acevedo, PhD, then at Stony Brook University (currently at University of California, Santa Barbara). "It isn't. Romantic love has the intensity, engagement and sexual chemistry that passionate love has, minus the obsessive component. Passionate or obsessive love includes feelings of uncertainty and anxiety. This kind of love helps drive the shorter relationships but not the longer ones."
These findings appear in the March issue of Review of General Psychology, published by the American Psychological Association.
Acevedo and co-researcher Arthur Aron, PhD, reviewed 25 studies with 6,070 individuals in short- and long-term relationships to find out whether romantic love is associated with more satisfaction. To determine this, they classified the relationships in each of the studies as romantic, passionate (romantic with obsession) or friendship-like love and categorized them as long- or short-term.
The researchers looked at 17 short-term relationship studies, which included 18- to 23-year-old college students who were single, dating or married, with the average relationship lasting less than four years. They also looked at 10 long-term relationship studies comprising middle-aged couples who were typically married 10 years or more. Two of the studies included both long- and short-term relationships in which it was possible to distinguish the two samples.
The review found that those who reported greater romantic love were more satisfied in both the short- and long-term relationships. Companion-like love was only moderately associated with satisfaction in both short- and long-term relationships. And those who reported greater passionate love in their relationships were more satisfied in the short term compared to the long term.
Couples who reported more satisfaction in their relationships also reported being happier and having higher self-esteem.
Feeling that a partner is "there for you" makes for a good relationship, Acevedo said, and facilitates feelings of romantic love. On the other hand, "feelings of insecurity are generally associated with lower satisfaction, and in some cases may spark conflict in the relationship. This can manifest into obsessive love," she said.
This discovery may change people's expectations of what they want in long-term relationships. According to the authors, companionship love, which is what many couples see as the natural progression of a successful relationship, may be an unnecessary compromise. "Couples should strive for love with all the trimmings," Acevedo said. "And couples who've been together a long time and wish to get back their romantic edge should know it is an attainable goal that, like most good things in life, requires energy and devotion."
Journal reference:
Bianca P. Acevedo and Arthur Aron. Does a long-term relationship kill romantic love? Review of General Psychology, 2009; 13 (1): 59 DOI: 10.1037/a0014226
Adapted from materials provided by American Psychological Association, via EurekAlert!, a service of AAAS.

Stranger Knows Best: Other People Know More About What Will Make Us Happy Than We Do

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ScienceDaily (Mar. 20, 2009) — Want to know what will make you happy? Then ask a total stranger -- or so says a new study from Harvard University, which shows that another person's experience is often more informative than your own best guess.

The study, which appears in the current issue of Science, was led by Daniel Gilbert, professor of psychology at Harvard and author of the 2007 bestseller "Stumbling on Happiness," along with Matthew Killingsworth and Rebecca Eyre, also of Harvard, and Timothy Wilson of the University of Virginia.
"If you want to know how much you will enjoy an experience, you are better off knowing how much someone else enjoyed it than knowing anything about the experience itself," says Gilbert. "Rather than closing our eyes and imagining the future, we should examine the experience of those who have been there."
Previous research in psychology, neuroscience, and behavioral economics has shown that people have difficulty predicting what they will like and how much they will like it, which leads them to make a wide variety of poor decisions. Interventions aimed at improving the accuracy with which people imagine future events have been generally unsuccessful.
So rather than trying to improve human imagination, Gilbert and his colleagues sought to eliminate it from the equation by asking people to predict how much they would enjoy a future event about which they knew absolutely nothing -- except how much a total stranger had enjoyed it. Amazingly enough, those people made extremely accurate predictions.
In one experiment, women predicted how much they would enjoy a "speed date" with a man. Some women read the man's personal profile and saw his photograph, and other women learned nothing whatsoever about the man, but did learn how much another woman (whom they had never met) had enjoyed dating him. Women who learned about a previous woman's experience did a much better job of predicting their own enjoyment of the speed date than did woman who studied the man's profile and photograph.
Interestingly, both groups of women mistakenly expected the profile and photo to lead to greater accuracy, and after the experiment was over both groups said they would strongly prefer to have the profile and photograph of their next date.
In the second experiment, two groups of participants were asked to predict how they would feel if they received negative personality feedback from a peer. Some participants were shown a complete written copy of the feedback. Other were shown nothing, and learned only how a total stranger had felt upon receiving the feedback. The latter group more accurately predicted their own reactions to the negative feedback. Once again, participants mistakenly guessed that a written copy of the feedback would be more informative than knowledge of a total stranger's experience.
"People do not realize what a powerful source of information another person's experience can be," says Gilbert, "because they mistakenly believe that everyone is remarkably different from everyone else. But the fact is that an alien who knew all the likes and dislikes of a single human being would know a great deal about the species. People believe that the best way to predict how happy they will be in the future is to know what their future holds, but what they should really want to know is how happy those who've been to the future actually turned out to be."
Gilbert's research was funded by the National Science Foundation.
Adapted from materials provided by Harvard University, via EurekAlert!, a service of AAAS.

Liking Sweets Makes Sense For Kids

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ScienceDaily (Mar. 20, 2009) — As any parent knows, children love sweet-tasting foods. Now, new research from the University of Washington and the Monell Center indicates that this heightened liking for sweetness has a biological basis and is related to children's high growth rate.

"The relationship between sweet preference and growth makes intuitive sense because when growth is rapid, caloric demands increase. Children are programmed to like sweet taste because it fills a biological need by pushing them towards energy sources," said Monell geneticist Danielle Reed, PhD, one of the study authors.
Across cultures, children prefer higher levels of sweetness in their foods as compared to adults, a pattern that declines during adolescence. To explore the biological underpinnings of this shift, Reed and University of Washington researcher Susan Coldwell, PhD, looked at sweet preference and biological measures of growth and physical maturation in 143 children between the ages of 11 and 15.
The findings, reported in the journal Physiology & Behavior, suggest that children's heightened liking for sweet taste is related to their high growth rate and that sweet preferences decline as children's physical growth slows and eventually stops.
Based on the results of sensory taste tests, children were classified according to their sweet taste preference into a 'high preference' or 'low preference' group. Children in the 'low preference' group also had lower levels of a biomarker (type I collagen cross-linked N-teleopeptides; NTx) associated with bone growth in children and adolescents.
"This gives us the first link between sweet preference and biological need," said Reed. "When markers of bone growth decline as children age, so does their preference for highly sweet solutions."
Other biological factors associated with adolescence, such as puberty or sex hormone levels, were not associated with sweet preference.
"We now know that sweet preference is related to physical growth. The next step is to identify the growth-related factor that is signaling the brain to influence sweet preference," said study lead author Coldwell, Washington Dental Service Endowed Professor and Associate Professor of Dental Public Health Sciences at the University of Washington School of Dentistry.
The research was funded by a grant to the University of Washington from the National Institute of Dental and Craniofacial Research (National Institutes of Health).
Adapted from materials provided by Monell Chemical Senses Center, via EurekAlert!, a service of AAAS.

Language Of Music Really Is Universal, Study Finds

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ScienceDaily (Mar. 20, 2009) — 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. 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.
In the new study, Fritz, Stefan Koelsch, and their colleagues wanted to find out whether the emotional aspects of Western music could be appreciated by people who had no prior exposure to it. Previous studies had asked similar questions about people with little experience with a particular musical form, for instance Westerners listening to Hindustani music, they said. But to really get at musical universals requires participants who are completely naïve to Western music.
Fritz enlisted members of the Mafa, one of about 250 ethnic groups in Cameroon. He traveled to the extreme north of the Mandara mountain ranges, where they live, with a laptop and sun collector to supply electricity in his backpack.
Their studies showed that both Western and Mafa listeners, who had never before heard Western music, could recognize emotional expressions of happiness, sadness, and fear in the music more often than would be expected by chance. However, they report that the Mafa showed considerable variability in their performance, with two of twenty-one study participants performing at chance level.
Both groups relied on similar characteristics of music to make those calls; both Mafas and Westerners relied on temporal cues and on mode for their judgment of emotional expressions, although this pattern was more marked in Western listeners.
By manipulating music, the researchers also found that both Western listeners and African listeners find original music more pleasant than altered versions. That preference is probably explained in part by the increased sensory dissonance of the manipulated tunes.
"In conclusion," the researchers wrote, "both Mafa and Western listeners showed an ability to recognize the three basic emotional expressions tested in this study from Western music above chance level. This indicates that these emotional expressions conveyed by the Western musical excerpts can be universally recognized, similar to the largely universal recognition of human emotional facial expression and emotional prosody." Prosody refers to the rhythm, stress, and intonation of connected speech.
The authors include Thomas Fritz, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Sebastian Jentschke, UCL Institute of Child Health, London, UK; Nathalie Gosselin, Universite´ de Montreal, Montreal, Canada; Daniela Sammler, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Isabelle Peretz, Universite´ de Montreal, Montreal, Canada; Robert Turner, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Angela D. Friederici, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; and Stefan Koelsch, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, University of Sussex, Falmer, UK.
Journal reference:
Thomas Fritz, Sebastian Jentschke, Nathalie Gosselin, Daniela Sammler, Isabelle Peretz, Robert Turner, Angela D. Friederici, Stefan Koelsch. Universal Recognition of Three Basic Emotions in Music. Current Biology, 2009; DOI: 10.1016/j.cub.2009.02.058
Adapted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.