Dontcha love the language academics use to title their papers?
The stuff inside this particular one is even better, though — as reported by the NY Times:
When dogs feel fundamentally positive about something or someone, their tails wag more to the right side of their rumps. When they have negative feelings, their tail wagging is biased to the left.
It happens just today I was thinking about symmetry and the human body — how there is apparent symmetry externally, but the internal organs are not symmetrical.
Which got me thinking specifically about the heart. Why is the heart on the left? Always on the left? Why aren’t there mirror people with right-sided hearts? Would a human with a heart exactly in the middle be . . . different? How? A different species? And I wonder what would it feel like, emotionally, to have a heart smack dab in the middle?
Don’t ask me why I was thinking all this btw. I have no idea. Now if I were a sci fi writer . . .
Anyway, I’m not, so back to the Times article — this biased whole tail wagging thing is because our brains (“our” meaning a whole lotta higher critters) aren’t symmetrical either. And of course the brain’s asymmetry casts a shadow visible on our external bodies, if you know where to look:
Research has shown that in most animals, including birds, fish and frogs, the left brain specializes in behaviors involving what the scientists call approach and energy enrichment. In humans, that means the left brain is associated with positive feelings, like love, a sense of attachment, a feeling of safety and calm. It is also associated with physiological markers, like a slow heart rate.
At a fundamental level, the right brain specializes in behaviors involving withdrawal and energy expenditure. In humans, these behaviors, like fleeing, are associated with feelings like fear and depression. Physiological signals include a rapid heart rate and the shutdown of the digestive system.
Because the left brain controls the right side of the body and the right brain controls the left side of the body, such asymmetries are usually manifest in opposite sides of the body. Thus many birds seek food with their right eye (left brain/nourishment) and watch for predators with their left eye (right brain/danger).
In humans, the muscles on the right side of the face tend to reflect happiness (left brain) whereas muscles on the left side of the face reflect unhappiness (right brain).
But that’s not all. Get this — one researcher speculates that the asymmetry of the brain evolved because of the assymetry of the internal organs:
The asymmetry [of the brain] may also arise from how major nerves in the body connect up to the brain, said Arthur D. Craig, a neuroanatomist at the Barrow Neurological Institute in Phoenix. Nerves that carry information from the skin, heart, liver, lungs and other internal organs are inherently asymmetrical, he said. Thus information from the body that prompts an animal to slow down, eat, relax and restore itself is biased toward the left brain. Information from the body that tells an animal to run, fight, breathe faster and look out for danger is biased toward the right brain.
My speculation about how a person with a heart in a different spot might feel different doesn’t sound quite so weird now, does it ;-)
(Humor me, please! LOL)
[tags] dogs, neuroscience [/tags]