If you are
thinking that your dog is "your child of fur", then the science has
his back. New research shows that when fellow dogs stare into our eyes, they
activate the same hormonal response that binds us to human babies. The study -
the first to demonstrate the effect of hormonal linkages between humans and
other types - may help explain how dogs became our companions for thousands of
years.
"It's an
incredible discovery that indicates dogs have hijacked the human bonding
system," says Brian Hare, a dog awareness expert at Duke University in
Durham, North Carolina, who was not involved in the work. Hare says the
discovery may lead to a better understanding of why service dogs help people
with autism and post-traumatic stress disorder. "A repetition of this
magnitude should be found because it is likely to have such far-reaching
effects."
Dogs are
already famous for their ability to interact with humans. Not only do walking
and frisbee walk, fangs seem to understand us in a way that no other animal can
understand. Point to something, for example, and your dog will look where you
refer - an intuitive reading of our intentions ("I'm trying to show you
something") that confuses our closest relative: the chimpanzee. People and
dogs also see each other's eyes during the reaction - a sign of understanding
and the emotion that close relatives of dogs and wolves interpret as hostility.
Also read: People Love Pets
It was this
mutual view that aroused the interest of Takifumi Kikusui, an animal behavior
at Azabu University in Sagamihara, Japan. The Kikusoy Lab studies oxytocin, a
hormone that plays a role in the bonding of mothers, confidence and altruism.
Other groups have shown that when a mother stares at her child's eyes, the
child's oxytocin levels rise, causing the child to return to his mother's eyes,
causing the mother to release more oxytocin, etc. A positive feedback loop
appears to create a strong emotional bond between a mother and a child during a
time when the child cannot express himself in other ways.
Kikusui - the
owner of the dog for more than 15 years - asked if the same was true of fangs.
“I love my dogs, and I always feel like they're more than a pet partner,” he says. So I began to wonder, "Why are they so close to humans?" Why are they in close contact with us? "
Kikusui and
his colleagues persuaded 30 of their friends and neighbors to bring their pets
to his laboratory. They also found a few people who were raising wolves as
pets. When each owner of his animal was brought to the laboratory, the
researchers collected urine from both of them and then asked his companions to
interact with their animal in a room together for 30 minutes. During this time,
owners were raising their animals and talking to them. The dogs and their
owners also looked into each other's eyes, each other for two minutes, and each
other for just a few seconds. (It was not surprising that the wolves
communicated so much with their owners.) After the time was up, the team took
urine samples again.
Mutual
squinting had a profound effect on both dogs and their owners. Among the duo
who spent the most time looking at each other's eyes, both males and females
saw a 130% increase in oxytocin levels, and both males and females increased by
300%. (Kikusoy was one of them, taking part in the experiment himself with two
standard poodle dogs, Anita and Jasmine.) The scientists saw no increase in
oxytocin in dogs and owners who spent little time staring at each other, or on
any of the duo wolf.
In a second
experiment, the team repeated the same basic procedure, except this time they
gave the dogs a nasal spray of oxytocin before they interacted with their
companions. There were also no wolves this time. Kikusoy laughs: "It would
be very dangerous to give the nose spray to the wolf." Female dogs giving
nasal spray spent 150% more time looking at their owners, who in turn saw a
300% increase in oxytocin levels. No effect has been observed in male dogs or
in dogs that are given nasal spray that contains only saline solution.
The results
indicate that human-dog interactions provoke the same type of positive oxytocin
feedback loop as seen between mothers and their babies, the team reported
online today in Science. This, in turn, may explain why we feel so close to our
dogs and vice versa. Kikusoy says that the nasal spray may have affected female
dogs only because oxytocin plays a greater role in female reproduction, as it
is important during labor and lactation.
He says that
this positive feedback episode may have played a critical role in domesticating
dogs. And since wolves turn into dogs, it is only those who can be associated
with humans who receive care and protection. Humans themselves may have
developed the ability to reciprocate and adapt the maternal feedback cycle to
new species. "This is our biggest guess," Kikusoy says, suggesting
that since oxytocin reduces anxiety, adaptation may be important to human
survival as well. "If humans are less stressful, it is better for their
health."
"I
definitely think oxytocin is involved in domestication," says Jessica
Oliva, Ph.D. A student at Monash University in Melbourne, Australia, whose work
recently demonstrated that the hormone enhances dogs' ability to understand the
human signal. However, she says, mutual stare does not happen in a vacuum; most
of these dogs may associate the behavior with food and play, both of which can
also boost oxytocin levels. Although we may view our dogs as our children, they
do not necessarily see our mothers. We might just be great friends giving them
a casual massage.
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