Most People Kiss The Right Way, Study Finds

By John Roach
for National Geographic News
February 12, 2003
It's that time of the year when romance is in the air and people
everywhere are planning where and when to plant the perfect kiss: after
a candlelit dinner at a fine restaurant, during a waltz on the dance
floor, or in the privacy of their own home.

But one thing lovers have little control over is how they'll turn their heads when they go in for the kiss. Chances are they'll turn their heads to the right, according to a German psychologist who observed the head-tilting preferences of 124 kissing couples.

The psychologist, Onur Güntürkün of Ruhr-Universität-Bochum, is not so much a voyeur as he is a scientist trying to figure out why humans have a preference for their right side, which from kissing a lover to kicking a soccer ball is twice as popular as the left.

"We humans are right-footed, right-handed, right-eared, and right-eyed. I want to know why," he said.

Researchers have long known that human embryos and newborn babies have a preference to turn their heads to the right and it is conceivable, said Güntürkün, that this early bias is the root of other biases that occur later in life.

The problem is that the head-turning behavior of newborns is thought to disappear by the time they reach half a year old, long before humans develop a preference for one side of the body or the other.

Scientists believe that for a link to be established between head-turning and other side-preferences such as the eye, ear, and foot, there must be an overlap in time with the establishment of these preferences.

Güntürkün said he never believed that head-turning bias simply disappeared when a baby reached the age of six months and so he went in search of a way to test for a head-turning bias in human adults.

Kissing Study

The search led him to airports, train stations, parks, and beaches in the United States, Turkey, and Germany. There, Güntürkün would pass the time looking for couples expressing their affections for each other.

"I tried to be as discrete as possible and I guess most couples didn't sense that they were observed," he said. "As soon as they had kissed, I walked away."

Güntürkün explained in his paper that to be included in this study, the act had to meet a few kissing criteria: lip contact, face-to-face positioning, no hand-held objects, and an obvious head-turning direction during the kiss.

It turns out that roughly twice as many people turn their heads to the right when they go in for a kiss than to the left. Of the 124 pairs observed, 80 turned their heads to the right and 44 to the left.

This right-kissing, two-to-one bias is the same ratio as the bias toward the right foot, ear, and eye, according to Güntürkün. Preference for the right hand is eight to one, but scientists believe it is skewed because of cultural pressures.

"These data suggest that a head-motor bias still persists in adulthood and could therefore modulate the establishment of various forms of sidedness over the entire lifetime," said Güntürkün.

Study Questioned

Chris McManus, a psychology professor at University College London and author of the book Right Hand, Left Hand published by Harvard University Press in 2002, questions the methodology of Güntürkün 's find.

McManus said that it may be possible that head-turning preferences of babies are the root of preferences for one side or the other, "but the only way to test the hypothesis is to follow infants whose head-turning direction is known."

Güntürkün did not know the couples he observed, so did not know if they turned their heads to the right or left as infants. However, Güntürkün believes his research may eventually show that head-turning preference is one of the very few sided behaviors controlled by genetics, and that all others are secondary.

Daniel Geschwind, a research scientist with the Center for Neurobehavioral Genetics at the University of California at Los Angeles, said it is unclear whether this head-turning behavior is related to other types of asymmetries such as being right-eared and right-eyed.

"The reason other asymmetries are interesting is they have a lot to do with early patterning, such as language," he said. Ear-sidedness, for example, is related to language. "It is unclear if this is related to any of that."

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