What does Warwick Schiller mean by attachment theory in horse training and where did the concept come from?

Warwick Schiller's application of attachment theory to horse training draws from the developmental psychology work of John Bowlby and Mary Ainsworth, who studied how infants form bonds with caregivers and what happens when those bonds are secure versus insecure. Schiller began exploring this framework after noticing that horses with behavioral problems — spookiness, buddy sour behavior, separation anxiety, inability to focus — consistently shared a common pattern: they had not formed a secure attachment to any human, and their relationship with humans was transactional at best. In Bowlby and Ainsworth's framework, a securely attached infant uses the caregiver as a safe base from which to explore the world. When something frightening happens, the infant returns to the caregiver for reassurance, regulates its distress through the relationship, and then ventures out to explore again. An insecurely attached infant cannot use the caregiver this way — either because the caregiver is unreliable, unpredictable, or emotionally unavailable — and as a result cannot self-regulate or explore confidently. Schiller observed this same pattern in horses. A horse that has a secure attachment to its handler — that genuinely trusts the human as a safe base — will look to the handler when uncertain rather than defaulting to flight, will regulate its emotional state through the relationship rather than through proximity to other horses, and will generally be easier, safer, and more willing to work with. A horse with an insecure attachment — regardless of how much technical training it has received — remains dependent on herd proximity, spooks readily in novel environments, and cannot settle without its buddies. Schiller's practical implication is that building secure attachment is not a soft or optional component of training — it is foundational infrastructure that determines how well all other training works. A horse with a secure human attachment learns faster, generalizes better, and handles stress more effectively than a technically trained horse without that relational foundation.