Interspecific social cognition in horses in their relationship with humans

Social cognition is the way in which an individual perceives and understands the individuals that surround him. It involves several cognitive skills such as :

• Communication skills
• Social learning, i.e learning how to perform a task through observing the said task carried out by another individual.
• Recognition of other individuals
• Understanding the emotions of others, or understanding their mental states (their intentions, perceptions, knowledge, beliefs…)

For social animals , like horses, social cognition is particularly important for the cohesion and survival of the group.  For example, the capacity to understand the emotions of other members of the group enables them to limit conflictual situations and favors harmony in the group. Understanding mental states can help in hiding a food source from others to avoid it being stolen. It can also incite one horse to follow another member of the group who knows where a food source is located. Social learning helps to solve a task much more quickly than learning through trial and error.

Since the horse has been domesticated for around 6000 years, and has a close relationship to humans, this social cognition could integrate understanding of human beings as well. This is known as « interspecific » social cognition (between different species). Interspecific social cognition can however be complex. Each different species has its own mode of communication (the signals used will be different) and will express emotions in a specific way, or will have different perception capacities.  For example the horse, unlike us, has a near panoramic vision, and can see for 340° all around… To understand huma,n beings the horse needs to integrate these differences.

Recognising other individuals

It has been shown that the horse recognises the humans that he knows both visually (even on photographs) and by the sound of their voice. The horse associates a voice to a visual aspect of the person, and will show signs of surprise if , after seeing someone familiar, he hears a different voice

Social learning

A recent study suggests that a horse will learn a task more quickly (pressing a button to open a lid on a container of food) if he has first observed a demonstration by a human tester, than if he has to learn the task alone.

Understanding our emotions

Recent studies, which have just been published, concern the horse being able to recognize human emotions expressed through our facial expressions. In 2016,  it was demonstrated that horses react differently when presented with photographs of a human face smiling (positive facial expression) or when presented with a photograph of an angry face (negative facial expression). In the latter case, their heart rate went up, and they looked at the photos of negative facial expressions with their left eye, which coincides with a lateralisation linked to negative stimuli. This study showed that not only do horses differentiate between photos of  positive and negative facial expressions , but that they also show an appropriate physiological response. This study therefore suggests that they recognize our emotions and understand the implications.

In 2018 a second study, with even more surprising results, was conducted. In this study,  the horses were again presented with photos showing positive or negative facial expressions, and then were, a few hours later, confronted with the person in the photograhs (this time wearing a neutral facial expression). Horses who had seen the photo of the negative expression took longer to approach the person and looked at him mainly with their left eye. Horses can thus use information about human emotions acquired previously to guide them in their future interactions with that person.

Pointing

The horse also seems tio understand a means of communication which is specific to humans : pointing. When choosing between two buckets of feed, the horse will prefer to go towards the bucket which is being pointed at by a human tester without any prior learning.  A horse will also try to communicate with humans is he wants to be fed for example. These requests are often made by looking alternately at the food and at the person, but if the person is not paying attention, the horse may also use tactile communication, by coming to touch the person with his muzzle to get his attention.  The horse will also prefer to ask for food from an attentive  person, than from someone paying no attention to him. He will prefer the tester facing him to one turrning his back, or a tester with open eyes to one with his eyes closed…..

Understanding our knowledge

It seems that the horse is capable of taking into account our perception, and at least one of our mental states. A recent study conducted in Japan, suggests that the horse can adapt his behaviour to what his handler knows or doesn’t know.  In this experiment, a bucket placed  next to the paddock,out of the horse’s reach, was then filled with feed. The horse needed to ask for help from his carer, also present near the paddock, to be able to get to the food. The results show that the horse in this situation reacts differently depending on whether his carer was or was not present when the food was placed in the bucket.  These results suggest that horses adapt their behaviour according to the level of knowledge of their handler. They would therefore appear to know whether the tester knows  that there is food in the bucket (« the horse knows the tester knows »), this corresponds to a high level cognitive phenomenen.

We carried out an experiment in a livery yard, to study in more detail how much the horse understands of human mental states. More specifically , the objective was to find out if  horses can deduce whether the experimenter is attentive or not to a situation , and adapt their behaviour accordingly.
To ascertain this, we used 15 horses from the livery yard (horses therefore with a particularly strong relationship with their owners) individually in an indoor school. In the first phase of the experiment, the horse was held by an assistant  facing a bucket, while a second person filled the bucket with feed. Two experimenters were present on either side of the bucket. One of them the « witness » was facing the bucket and could observe the scene. The other, a « non-witness » was standing with his back to the bucket and could not therefore see the feed being put in the bucket. The assistant then closed the bucket with a lid which the horse would not be able to open. The second phase could then begin. Both experimenters then turned to face the horse and the assistants left the school and the horse was left free. The horse’s behaviour towards the experimenters was then filmed for 2 minutes.

The analysis of the horses’ behaviour revealed several interesting aspects. Firstly, as the horses could not get to the feed themselves, they turned to the experimenters to get help. There was therefore firstly a desire to communicate with the experimenters. Moreover, the horses demanded more from the witness than from the non-witness : they spent more time looking at him, and more often than not touched him with their muzzle. This preference for the witness suggests that the horses used the the fact that he was attentive during the first phase to adapt their behaviour in the second phase. Unlike the previous experiments, the horse did not just deduce whether a human was being attentive to him. In all likelihood, he understood that the experimenters had – in a near past – been attentive or not to an event. The horse recalled this information, and subsequently used it. This study suggests cgnitive faculties in the horse, that we had so far not suspected.