Monday, June 08, 2015

Laterality isn't all one-sided

Idiosyncratic motor laterality in the horse - Applied Animal Behaviour Science

Equine Eyesight--Equus

There are a lot of common misconceptions about horses and how they function in the world.  We humans try to ferret out the details of other creatures' lives, but we're prone to guesswork and "common knowledge" responses.  The two articles linked above are worthy of consideration as you stand staring at your horse and wondering...WTH?

The first, scholarly study focuses on whether horses experience "handedness"--laterality--in movement.  Is your horse right-side-dominant or left-side-dominant?  Do you care?

It's not possible to tell from a still picture which side of
your horse is dominant.  Dolly may be right-sided by default
due to arthritis in her left shoulder.

You should care.  Training is a lot less frustrating when an owner gets where the horse is coming from (and I don't mean the neighbor's carrot patch).  Your horse actually does have a left/right preference, and it's not about weakness on one side or the other. It's about his brain.  Interestingly, the study found that males tend to be more left-footed than females.  Huh.  I've certainly seen that in action with my own horses, as Zip is totally a Lefty while Dolly is a Righty all the way.  I'm a Righty, too.  We've bonded.

If you've ever tried to write with your less dominant hand, you know that it's not all about practice. Practice will make it better. Some people are born (or can very effectively become) bilateral.  I'm not sure the same applies to horses only because they have no particular motivation to change.

Training is about change.  If the horse changes his behavior for his own purposes, it's usually effective, efficient and pretty hard to unchange.  He may change his route around the pasture because he's found where the best grass grows.  He may change his position in the lineup at the gate because he's less likely to get the snot kicked out of him if he moves back a space.  He may not have any particular desire to change from left- to right-side-dominant.  That's where horses and trainers butt heads.  We humans are a smidge self-centered, and we sometimes ignore that the four-legged partner we're working with doesn't give a rat's ass what we think he should look like as he cruises around the pen.  We're very convincing, but not very understanding.

Now, I'm a Righty, as noted.  I'm right hand, left leg, left eye dominant.  Go figure.  Zip is a Lefty.  This has always presented a minor issue as his preference for working beautifully to the left doesn't mesh well with my weaker right leg.  I can keep him reasonably straight going to the right.  To the left, I'm a little short on pressure with the outside leg, so he tends to drift out through the corners.  I correct this as much as possible by working hard to keep my right leg strong, but brains are brains, and I'm just slower on that side.  Period.

The other issue is the Split Brain Theory of horse life.  Our brains are split. There's a fascinating book (I recommend the audio version), Tales From Both Sides of the Brain: A Life in Neuroscience, by Michael S. Gazzaniga that should be required reading for anyone interested in interacting with any other thinking being.  It's that book that got me thinking about whether or not the horse really has such a definitive split between the hemispheres as we've been led by popular press to believe.  If it's as unclear to science as it appears to be, then why is it so ridiculously "obvious" to horsemen?

That's because we believe what we're told and few of us are researchers into such esoteric subjects as a career choice.

The second article speaks to the visual differences between us and our horses.  I, for one, believed the stories that said horses are completely monocular--they only see with one eye at a time, hence the spooky thing when something appears to move from one visual field to the other.  Not so.  It's not that "he's never seen it from that side of his brain."  They actually can use binocular vision, and they do so regularly.  When a horse picks his head up from his hay pile and stares across the pasture at you with both eyes, he's seeing you with both eyes, and you are totally 3D.  He knows how far away you are, how fast you're approaching, and how fast he needs to turn and run to get out of working.  Apparently what causes the spook is that for the instant between binocular vision (when he sees the object ahead with both eyes) and when it moves into monocular vision, there's a bit of a disconnect.  He loses focus and has to take a moment to determine just how far away, how big, and how fast-moving (or not) the object might be.  Being a self-protective sort, he quickly moves away from it until he can sort this out.

Dakota was likely born left-side-dominant, but if you look
closely at his left chest, you'll see the dimples of an impact
injury he probably suffered years ago that prevents him from
fully extending his left foreleg.  He's permanently confused.

Some horses have wide foreheads, which places the eyes farther to the sides and creates a larger blind spot. If the average horse needs you to be four feet in front of him for him to see you with both eyes, the wide-forehead guy might need you to be six or eight feet away.  The guy with the narrow head with eyes more frontally-aimed might not need as much distance.  The wide-forehead horse is likely to be spookier and rely more heavily on his trust in his rider/handler.  The narrow-forehead guy, as long as he doesn't have a lump between his eyes, might handle foreign objects more easily.

Your assignment this week is to look at your horse.  Figure out which side is dominant, and figure out just where his blind spot begins.  You might find the solution to some of the behavioral issues you're dealing with staring you Right (or Left) in the face.

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