They use it whether towards conspecifics or interspecifics (perhaps especially humans), and just as each word in human spoken language has a meaning which has been learned by individuals within our species, each slight of body language displayed by the horse is universal within their species (although still has to be learned and practiced), and is more and more understood by humans also.  To be able to display (and to understand from another) an emotion, an intention, a belief about status, a need or desire, a location reference, a like or dislike, an invitation or rebuttal and possibly many more, as horses can, could be described as linguistic intelligence.  Of course, vocal ‘language’ of horses is also a factor.  Vocalisations of pain or desperation for a resource are different and perhaps more ‘pained’ than those of arousal during play.  Different sounds have varied meanings, from play excitement or invitation, distress from being separated, those induced by pain, fearful neighs (Browning, 2009) – all of these, it could be said, count as a type of verbal language, even if the sounds made are not shaped by the tongue and lips to form words such as our own, they are, nonetheless, shaped to create specific meaning to others.

Adaptive Intelligence

As mentioned in various points, a horse’s adaptive abilities are strong in that they are able to acknowledge their environment, including others within it, and adapt their behaviours (perhaps by trial and error in some cases) to suit.  Perhaps this has contributed strongly to the convergent evolution of the domestic horse and humans.  It also encompasses problem solving abilities, as well as others linked with other ‘types’ of intelligence

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Emotional Intelligence

Another huge one is emotional intelligence. We have discussed that equines have the ability to perceive emotional states of others.  How about the ability to experience emotions themselves?  If one steps away from the caution of anthropomorphising, it is acknowledged that the mammalian brain (so, including equines and humans) is at least in part reliant on the limbic system to create and ‘feel’ or express emotions, as well as store memories of stimuli that have previously triggered certain emotions and emotional responses.  Roxo et al (2011) explored postulations from neuroscientists, psychologists, psychiatrists and neurologists regarding the structure of the limbic system, its components, how emotions are created and which areas of the brain are involved, including whether there is or has to be interaction between different structures or areas.  This review includes hypotheses as far back as those of Aristotle in 384-322 BC, with further progress made by Galen (130-200 AD), but reports in detail are explored from the early 19th century.  Of course, in the 16th century, Descartes famously postulated that animals were incapable of having experiences, and were basically automata. 

Later, John B. Watson proposed that all behaviour was as a result of the environment around the organism, and a stimulus-response mechanism as a result of conditioning.  This theory is referred to as behaviourism and didn’t take emotional experience into account.  Although the subject is still being researched, the consensus appears to be that the limbic system (encompassing amygdala, hippocampus, hypothalamus, cingulate gyrus and orbitofrontal gyrus) is at least in part responsible for emotional formation, leading to behavioural mechanisms and at least short term, if not long-term potentiation.  With sentience and affective states in mind, it is strange (to put it mildly) that certain human behaviours are still legal when it comes to equines, given that the UK Government passed the Animal Sentience Bill earlier this year, stating that it is recognised that all vertebrates are indeed sentient.  For example, why is it still ok for us to cause physical pain? Emotional distress?

Cross-over of the intelligences suggested above is also very likely as situations often involve multiple aspects. Some horses may have a more enhanced spatial intelligence than another, but a weaker social intelligence.  Perhaps it’s fluid – maybe certain circumstances facilitate particular intelligences more than others. Lots to consider!

More recent studies by a team at the Research Institute of Molecular Pathology headed by Wulf Haubensak (2018) have utilised pharmacogenetics, optogenetics and viral tracing to explore brain mapping and observation of responses by intricate systems of the frontal lobes.  They have observed that emotions are mapped by antagonistic circuits of neurons, with each emotion (reward vs fear) effectively having its own set of conditioned neural pathways within the lateral central amygdala (CE1).  These exclusive networks work in a gated fashion, where high fear stimuli close the gate against the reward network and high reward stimuli open the gate for positive response and close against the fear ‘network’.  Haubensak describes this as: