A recent article looking for ways to improve research into the preferences of horses found that horses can be taught to communicate preferences to their handlers by using symbols. Mejdell et al (2016) used positive reinforcement training to teach 23 horses to choose whether or not to wear a blanket, and tested the efficacy of the training through weather challenges. They predicted that if the horses had correctly learned to discriminate the symbols they would vary their choices based on the weather.
Horses were trained over 14 days to understand the consequences of choosing the ‘blanket on’ symbol versus the ‘blanket off’ symbol both in their home box and outdoors. At first the horse was taught to touch a single board with their nose and were rewarded for this. Then the relevant symbol was shown to the horse (i.e. ‘blanket on’ symbol if no blanket was worn at the time of the training), the horse was rewarded for touching it, and the action was carried out. ‘Blanket on’ and ‘blanket off’ symbols were then presented together, and only the relevant choice was rewarded until no mistakes were made.
Finally a ‘no change’ symbol was added with the other relevant symbol. This was the beginning of introducing choice to the horse. Either choice was rewarded and carried out accordingly. A choice of ‘no change’ prompted the trainers to perform a sham handling of the horse as if putting on a blanket or taking one off to prevent horses from choosing ‘no change’ simply to avoid being touched. Random choices were then presented, with only the relevant choices being rewarded, and irrelevant ones being ignored until no mistakes were made. When horses passed this stage, they moved on to temperature challenge tests to ensure they understood the consequences of choosing different symbols.
For the temperature challenge, horses were rugged heavily indoors until they were obviously warm, then presented with the choices of ‘no change’ or ‘blanket off’ until they reliably chose the obvious answer (but all choices were still rewarded). The cold challenge was outdoors until mild signs of temperature discomfort were shown, then the ‘no change’ or ‘blanket on’ choices were given. After passing this stage, the horses were ready for preference testing.
On two warm, pleasant days and two cold, unpleasant days, the horses were taken from their paddock to the test area in a random state of blanketed or not blanketed. The symbols were varied in position and relative distance to each other. The horses’ responses were very consistent with the weather; all horses chose ‘blanket off’ on the warmer days when wearing one, or ‘no change’ when not. On the cold days, all but two horses chose ‘no change’ when wearing one or ‘blanket on’ when not.
The researchers concluded this kind of training is an effective way to study preferences in horses, and can be used in the field in place of less portable Y-maze testing that has been done previously to determine preference.
The article is open access and can be found with this reference:
Mejdell, C; Buvik, T; Jørgensen, G; Bøe, K. (2016) Horses can learn to use symbols to communicate their preferences. Applied Animal Behaviour Science, 184 pp 66-73. https://doi.org/10.1016/j.applanim.2016.07.014