Question: how do you measure emotional responses in animals with different physiologies and behaviors?

Ben Brilot answered on 11 Mar 2013:

That’s a very, very good question and it’s one that a lot of scientists are trying to figure out. One argument is this: there are a number of ways in which you can tell what sort of emotional state another person is in. The most obvious is that they tell you (“I feel afraid”), but also you’d see things like their heart would be beating very fast, they might be sweating, certain parts of their brain might be very active, and certain hormones might have increased their concentration in the blood (like adrenaline). Although other animals do differ a bit in their physiology and brain structure, they’re similar enough to us that we can still see all of these changes in an animal that is in a situation where it should be ‘afraid’.

As for behaviour, the same thing goes: animals often do very similar things to us in a similar emotional state. So when they’re afraid animals will freeze or find somewhere to hide, or run away or put up a fight. They obviously differ to an extent from us (you don’t tend to try and run down a hole like a rat might), but again you can say that it’s the same type of behaviour: trying to get away, avoid or confront the thing that they fear. It’s important to keep the differences in mind: you have to remember that what we’re afraid of might not scare another animal (and similarly the things that they fear might not even register with us – I’ve seen a bird be very scared of a bit of black tape on a ceiling).