Affective States—How Horses’ Emotions Impact our Interactions
When a horse is worried about something, he doesn’t pay much attention to you. That’s when
his ‘arousal’ level is high. A horse can also be optimistic or pessimistic—he can expect a new experience to be positive
or negative. That’s his ‘emotional state’. His level of arousal and emotional state taken together are his affective state and dictate the quality of work he is capable of and what kind of reinforcement will be most effective for
training at that moment. Being able to read a horse’s affective state and respond appropriately in the moment could
make the difference between raising his arousal level further until he can no longer interact with you and making significant progress towards your goal, whether that goal is quality time with
him or higher steps in piaffe.

How Arousal is Created We don’t yet know exactly what levels of arousal are ideal for training new behaviours.
However, common sense and practical experience agree that if the horse is not aroused enough (if he is asleep), or if he is too aroused (if he fears for his life), there will be little useful
interaction between horse and human.
Determining what level of arousal will be best for the intended activity with a horse could
greatly benefit the interaction. For a therapy session, a very relaxed horse with a low level of
arousal is preferred. For resolving a behaviour problem, a higher level of arousal will be needed
so the horse is motivated to trial new responses and find the correct one. For shaping a trained
behaviour, medium arousal will be best, so the horse can think about what is being asked.

How Negative Affective States are Created
We know more about negative affective states than positive because animal welfare criteria
used to be based on the absence of negatives rather than the presence of positives. Positive
experiences were finally introduced in the 2020 Five Domains Model.
When a horse’s expectations of the outcome of certain behaviours or events are not met, the
difference between expectations and actual outcome creates frustration. Frustration in any or
all of the four physical domains (Nutrition, Physical Environment, Health, and Behavioural
Interactions) will create a negative state in the fifth Mental domain. This negative state can
contribute to aggressive behaviour and, if frustration continues, will create a long term negative
outlook. The use of punishment in training can also contribute to a negative state.

How Positive Affective States are Created
Use of the principles of equitation science in training has been shown to help avoid negative
affective states during training. For welfare, however, it is not enough to avoid the negative.
Working actively to help create a positive experience for the horse will contribute to positive
affect and relationship.
In a study by Freymond et al, horses trained with addition reinforcement (where something
pleasant is given to the horse to reinforce correct behaviour) were found to have more positive
emotional states than those trained with subtraction reinforcement (where something
unpleasant is taken away to reinforce correct behaviour). Interestingly though, after the training
session the subtraction-reinforced horses experienced a more positive overall emotional state
than the addition-reinforced horses had. This suggests that trainers and owners employing
combined reinforcement (use of both addition and subtraction reinforcement) may be able to
positively influence their horse’s mood.

Conclusion
Awareness of how a horse is currently feeling is a great asset to any horse person. This
knowledge makes it easier to predict what the horse will do in any given situation, enhancing
safety and even making it possible to change plans to create a positive experience for the
horse.
Keeping the lowest level of arousal required for the activity is essential to good training,
positive welfare, and good relationship. Not everything in the human-horse relationship is going
to contribute to a positive emotional state (for example, horses are unlikely to ask for a
vaccination!), but even the negatives can be countered in other ways to develop an overall
positive affective state in a horse.

Bibliography
Creighton, E. (2007) Equine learning behaviour: limits of ability and ability limits of trainers.
Behav. Process. 76, 43–44.
Freymond SB; Briefer EF; Zollinger A; Gindrat-von Allmen Y; Wyss C; and Bachmann I. (2014)
Behaviour of horses in a judgment bias test associated with positive or negative reinforcement.
Appl. Anim. Behav. Sci. 158, 34–45.
Mellor, DJ; Beausoleil, NJ; Littlewood, KE; McLean, AN; McGreevy, PD; Jones, B; and Wilkins,
C. (2020) The 2020 Five Domains Model: Including Human-Animal Interactions in Assessments
of Animal Welfare. Animals 10, 1870. Open access: https://www.mdpi.com/
2076-2615/10/10/1870
Olczak, K., Nowicki, J., and Klocek, C. (2016) Motivation, stress, and learning–critical
characteristics that influence the horses’ value and training method–a review. Ann. Anim. Sci.
16, 641–652.
Starling, MJ; Branson, N; Cody, D; and McGreevy, PD. (2013) Conceptualising the Impact of
Arousal and Affective State on Training Outcomes of Operant Conditioning. Animals 3. Open
access: https://www.mdpi.com/2076-2615/3/2/300/pdf