Aids are physiological responses to stimulus. Aids do not involve memory. Cues are a signal for a specific learned behavior. It involves memory.
An aid would be more in the line of putting your calf on the horse's sides to raise his back--it's an automatic physical response. A cue for a learned behavior, for example: wiggling your index finger for the horse to back up. Bookmark this page: http://iceryder.net/aids.html Judy
