We don't know what other humans are feeling most of the time!
Seriously, we don't, in general, know what we ourselves are feeling!
So we do assume that that person is "sad" when perhaps she is feeling anxious and excited and confused
- or that the orang is sad (when in fact she is hungry or curious, but she has those eyes!).
My way to express excitement or grief may be seriously different from yours! And that is true for people within the same culture!
(Last Tuesday's NYTimes had an interesting article on the role and effect of crying, how there are cultural expectations of how people "ought" to express themselves and the consequences for people who - for whatever reason - do not follow the script.)
And yet we debate not only whether animals have feelings, but just what those feeling are.
How do you feel about this? (No head bobbing or pacing, please)
An interesting point zooplantman and one I had not thought of. I suppose that, for the majority of people (in the western culture at least) crying, for example is an expression of sadness. It is fundamentally the same with animals and an ethological study can often identify many of these expressions so that we can learn - to an extent - what the animal is feeling.
For example, I was reading an article recently about chimpanzee body language: a pout is used as a greeting, dropping the head is a request for grooming, grins show fear, excitement or strength etc. By learning and then being able to read this body language we can begin to learn about animals' lives.
However, behaviour study is a relatively new discipline and, as such, there are still many things that we misinterpret or cannot interpret at all. Also, as you said certain individuals do not fit the pattern so all are careful observations are useless. Then there are different cultures, in humans, there are only four universal facial expressions, the rest are cultural and apparently this is the same with animals.
As such, it is incredibly difficult to determine what an animal is thinking however I believe that emotions are shared between us and the rest of the animal kingdom. After all, a few million years of evolution can't have made us that different.
It's an interesting topic...
