If you feel like your horse is part of you it's probably because you share a special state called "co-being."
At least that's what the study "Co-being and intra-action in horse-human relationships: a multi-species ethnography of be(com)ing human and be(com)ing horse," would suggest. The study, which was performed by Norwegian and American researchers and published in the August 2013 edition of Social Anthropology, found that riders and horses can enter into a unique state of interspecies "co-being" with one other.
Co-being refers to a state of relationship in which each partner evolves to "fit" better with the other, both physically and mentally.
Anita Maurstad, PhD, professor and researcher in the Department of Cultural Sciences in the Tromsø University Museum at the University of Tromsø in Norway, explained this phenomenon in a 2013 interview with The Horse.
"As riders get to know their horses, they attune to them--they learn both mental and somatic (physical) ways of acting versus their partner. Horses, too, attune to their humans; thus, co-being is a good analytical concept for speaking about these aspects of the relationship."
However, co-being is more than just the popular "mirror" theory that horses are "reflections" of their riders. In co-being, riders "get to know their horses as personalities through ongoing processes of deep engagement," Maurstad explains.
"They see horses as different personalities, both in the sense of horses being different personalities individually, and being different personalities from themselves, the humans. Riders do not see their horses as passive reflections of themselves."
Maurstad and her fellow researchers interviewed 60 male and female riders in North America and Norway to better understand the effect of riding and their relationship with their horses. They wanted to understand why they rode, how this activity influenced them as a person, and how it influenced their family life. It was the participants' responses that led the researchers to explore the concept of co-being "as a vital element to understanding the relationship."
Through her research Maurstad found that each species learns to adapt physically to the other in unique ways for the specific riding partnership; humans learn to act and communicate in ways that work with their particular horse, and horses learn to act and communicate in ways that work with their particular rider.
"(Humans) are balancing according to a feel of the other, the horse, attuning their bodies to sensations of the horse bodies," Maurstad and her colleagues state in their study. "Action and response between the species bring about riding as a collaborative practice, where bodies become in sync. And sync is a product of intra-action in that both are changed through a process of training from the meeting between the two--literally flesh to flesh."
However, this kind of connection can only develop over time.