McGreevy, P.D., McLean, A.N., Thomson, P.C., 2009b. SMART: Sensitivity Models for Animals in Response to Training. The Veterinary Journal.
Trained responses are said to be under stimulus control when they appear reliably and exclusively on cue. The SMART system is a conceptual, three-dimensional graphic that uses four quadrants to chart a horse’s responsiveness to various cues from two reins and the trainer’s legs and seat. The current plots have been designed for ridden horses. The models assume that the trainer’s cues are bilaterally equivalent, unless the intention is to signal a turn or a lateral movement. The extent to which ‘go’ signals manifest as straight, forward locomotion reflect the bilateral balance of the horse’s reactions to the trainer. The Z-axis shows the probability of a favourable response for the specific strength of stimulus from the trainer relative to competing stimuli from other sources. Where Z is 0 for a particular value of X and Y, the horse shows no desired response to the trainer. The X-axis shows left versus right movement; the Y-axis shows ‘stop’ versus ‘go’.