Published in the Scottish edition of Equi-ads 2013:
Take a break
Any good horse trainer will advise that when you are teaching your horse something new, you should take frequent short breaks and allow your horse to rest. We know from experience that this improves training results, but maybe not exactly why.
In 'Evidence-Based Horsemanship', Dr Stephen Peters comments on recent results using brain imaging (fMRI) to observe brain activity in people performing cognitive tasks such as responding to questions or performing motor tasks.
Researchers who allowed subjects to rest in the fMRI between tasks found that the same brain areas used in performing the task were still being used by the subjects while resting. When retested, the subjects also seemed to incorporate the knowledge from that task better than subjects who were not exposed to a delay.
It's not proven, but I'd put good money on this working much the same way with horses - so do give them lots of short breaks while you are training, where they can keep learning without you having to lift a finger!