The bond of strider to their person is a very strong emotional connection. Its like being accepted into the herd. Horses think in terms of we. They dont think in terms of I. Think is not the right word either as how a strider feels coupled with their body language and movements that produce their 'language'.
The drykas and the strider would have an understanding. Its not unlike the drykas hand sign as the body sign of the striders add to the feel that one gets from the strider. Goss said that a strider is on the intelligence level of a teenager. Thats pretty smart. So they would have strong opinions and emotions coupled with their body language. The drykas, their rider, is the same way. The drykas are an emotional people a showy people so are horses in general. Horses are huge show offs and very expressive. This translates into the bond.
Understanding herd dynamics would put the bond into perspective.