Which restraint device is described as an old and simple method that stimulates a horse's nerves?

The lip twitch is a traditional restraint device used in handling horses. It consists of a tool that gently pinches the sensitive skin of the horse's upper lip, which stimulates nerve endings in that area. This stimulation can create a calming effect on the horse, allowing for easier handling during procedures such as grooming, veterinary examinations, or other activities that may be stressful for the animal.

The effectiveness of the lip twitch lies in its ability to divert the horse's attention from the stressor, helping to reduce anxiety and resistance. It is essential to use this tool properly to avoid causing unnecessary pain or distress to the horse. This method has been utilized for a long time due to its simplicity and the quick results it often yields when dealing with untrained or nervous horses.

In contrast, the other devices mentioned have different applications. A chain shank is usually more for leading or controlling a horse’s head, the nose lead is a type of halter that applies pressure to the nose, and hobbles are used to limit a horse's movement by securing its legs together. Each of these serves distinct purposes and is chosen based on the specific needs of the situation or the horse's behavior.