Can Animals Have A Good Life?
What makes for a good life? Animal welfare advocates have predominantly focused on reducing pain, suffering, and distress, and on making animals’ living conditions more like natural ones. When emotional states are considered, it is typically to mitigate negative ones such as boredom, frustration, and depression.
But the absence of suffering is not enough to make life good. In our own lives, for example, there are many subjective factors that are also important for happiness. In this recent review, the authors summarize research on how happiness in humans is defined and measured, and connect it to what we know — and still need to learn — about happiness in animals. Developing a better understanding of animal happiness will help advocates increase the positive aspects of animals’ lives, not simply reduce the negative ones.
Human happiness consists of two main components. The cognitive component describes people’s perceptions of their quality of their life compared to their expectations. The affective component describes subjective pleasant or unpleasant feelings that are longer-term than emotions and moods. Research has found that happiness is dictated by the frequency, not intensity, of positive affect, so affective happiness is typically measured as the ratio of positive and negative affect over a long period of time.
There are several reasons to believe that affective, not cognitive, happiness is dominant in animals. From an evolutionary point of view, studies have shown that affective processes are older than cognitive processes. In fact, we do not know if animals have the ability to conceptualize the quality of their own life, the key component of cognitive happiness. And research in humans has shown that the affective component of happiness is more important than the cognitive component.
The gold standard for measuring affective happiness in humans is self-reports of how people generally feel. Although this is not possible in animals, indirect methods used for human infants are more readily adapted. One popular method is to use proxy reports of affect such as the opinion of a caretaker or expert. However, proxy reports have been shown to have limited accuracy in experiments with human infants and chimpanzees.
Another method is monitoring physiological changes in hormone levels, immune system function, or cardiovascular health. These factors have been linked to affective happiness in humans and may be promising future tools for evaluating happiness in animals. However, because it is impossible to compare the results to self-reports as is done in humans, researchers may be limited to validate these techniques on humans, hoping that similar mechanisms are present in animals.
Behavioral indicators such as posture, vocalization, and play behavior can provide information about affect in a given moment. When observed over long periods of time, these indicators can serve as a measure of typical affect. A simpler behavioral test for measuring long-term affect is the judgement bias test. This test measures how “optimistic” animals are when presented with a new stimulus. Animals who demonstrate more curiosity are judged to have higher long-term affect, while animals who are predisposed to think the stimulus is negative are judged to have lower long-term affect. Similar tests using cognitive traits such as attention and memory have also been used to measure affect in animals.
Particularly exciting is the possibility of new research and technology opening the door to automatic measurement of affective happiness in farmed animals, allowing advocates to identify conditions that most improve animal well-being. Taken together, research on defining and measuring affective happiness in animals will allow the animal welfare community to more effectively improve the lives of animals.