We have to work this out ourselves because I do not think that we can rely on the experts and reference books because this is a developing area of understanding for people. The short answer is that we don’t know for sure if cats understand human emotions. However, my gut feeling is that they do and I will explain why. I would welcome the thoughts of visitors in comments.
It seems to me that humans present their emotions to the world in at least two ways (1) their facial expression and (2) their actions, behavior and body language while they are feeling a specific emotion.
For example, if a cat owner is angry or frustrated her face looks different to when she is happy. Her behavior and body language will show signs of anxiety and frustration. She might raise her voice and dismiss her cat at that moment. She might slam a door or argue with somebody. She might be unexpectedly still for a while or cry. There are a myriad of subtle behavioral signals expressing emotions.
Domestic cats are very good observers. It is known that they learn by observation from their mother in the wild. That’s the way their mother teaches them, by demonstration. And there are numerous instances on video on the Internet of cats learning by observation to make the best of their lives living with people, such as opening doors and knowing when to ask for food.
Therefore, it is not unreasonable to suppose that cats can recognize human facial expressions. A domestic cat won’t know the meaning of the words ‘anxiety’, ‘anger’ or ‘contentment’. However domestic cats can recognize behavior caused by anxiety, anger and contentment. Therefore indirectly they understand human emotions at least to a limited extent.
As for the shape and configuration of a human facial expression, there is an interesting article in the Times this morning about horses. I don’t know whether horses are smarter than cats. Cats are predators and have to hunt. They use their intelligence when hunting. Horses are herbivores. Arguably they need less intelligence to survive. Anyway, for the sake of this discussion I will presume that they have similar intelligence.
A recent study, published in the journal Current Biology, carried out by scientists from the universities of Sussex and Portsmouth in the UK discovered that horses can recognise the expressions of people.
Horses were presented with an image of a woman who was either happy or angry. A few hours later the same woman resented herself to the horses in person with a neutral expression. It is known that when a horse feels threatened they look at the threat with their left eye and when not threatened they look at the person or animal with their right eye.
In this study the researchers showed that the horses looked at the woman with their left eye if they had been presented with a picture of her being angry earlier. Conversely, when the previous image was one of happiness they looked at the woman with their right eye.
It makes sense that domestic animals are able to recognize human expressions and I would argue, therefore, that they also recognize human emotions through their actions. It makes sense because it goes to survival ultimately. A cat should modify her behaviour dependent upon her human owner’s emotion. It would pay to avoid an owner who is angry and upset but go towards and be friendly towards an owner who is happy and contented.
In conclusion, therefore, in answer to the question, “do cats understand human emotions?” my current thinking is that they do understand them to a limited extent through the person’s facial expressions, their behavior and body language but they will not understand the definition of emotions i.e. they cannot label a form of human behavior arising from specific emotions.