05/29/2026
Brilliantly presented powerful information-
When people talk about laterality in horses, the conversation often gets simplified into “left brained/right brained” or a horse simply being stiff on one side and hollow on the other, but laterality is much more layered than that.
One layer involves sensory preference, particularly which eye the horse prefers to use when observing something.
Studies suggest that information from the left eye is primarily processed by the right hemisphere of the brain, while information from the right eye is processed by the left hemisphere.
Those hemispheres process information differently.
The right hemisphere is associated with stronger emotional arousal, rapid responses, and physiological stress reactions. The left hemisphere is more associated with familiar routines and learned patterns.
This helps explain why horses often prefer to keep unfamiliar or suspicious stimuli in the left eye. They are processing that information through the part of the brain that is more specialized for assessing novelty and potential threat.
But laterality doesn’t stop at sensory processing.
There is also an anatomical layer.
The horse’s internal anatomy is not perfectly symmetrical (neither is ours). Organs such as the liver and lungs have heavier right lobes, which influences how weight is distributed internally. In response, horses often develop increased contraction through the left side of the body as a way of counterbalancing that asymmetry.
Over time, those tendencies can influence another layer of laterality: habitual muscular contraction patterns.
Habitual posture is essentially the body’s default unconscious organization based on resting muscle tone and there are many ways those patterns become established.
Pain and injury can create protective compensations through the withdrawal reflex.
Repeated exposure to stress or startle responses can habituate associated muscle contractions until the horse no longer realizes they are holding those patterns.
Repetitive movement patterns can also shape the body over time. Hauling, living on a slope, uneven hoof balance, or carrying a crooked rider can all gradually influence posture and coordination until those patterns become unconscious defaults.
All of these layers influence each other.
Sensory preference can influence movement.
Movement patterns influence muscular development and posture.
Posture influences balance, coordination, and nervous system organization.
This is why I don’t think the goal should necessarily be straightness.
In fact, I’ve heard it suggested that the word often translated as “straightness” in the training scale may be more accurately understood as balance.
That perspective makes sense to me.
The goal is not to create a horse that is perfectly symmetrical, but to help the horse become more comfortable, organized, and fluid using both sides of the body with greater ease and adaptability.
Part of that involves restoring access to areas that have become limited by chronic tension or motor-sensory amnesia.
And part of it involves training practices that thoughtfully develop both sides of the horse through movement as well as exposure, handling, and interaction with their environment.
Balance has a physical component but it also has neurological, emotional, and behavioral elements.
