From Animals Make Us Human: Creating the Best Life for Animals by Temple Grandin:
I believe that the best way to create good living conditions for any animal, whether it’s a captive animal living in a zoo, a farm animal, or a pet, is to base animal welfare programs on the core emotion systems in the brain. My theory is that the environment animals live in should activate their positive emotions as much as possible, and not activate their negative emotions any more than necessary. If we get the animal’s emotions right, we will have fewer problem behaviors.
That might sound like a radical statement, but some of the research in neuroscience has been showing that emotions drive behavior, and my own thirty-five years of experience working with animals have shown me that this is true. Emotions come first. You have to go back to the brain to understand animal welfare.
Of course, usually — though not always — the more freedom you give an animal to act naturally, the better, because normal behaviors evolved to satisfy the core emotions. When a hen hides to lay her eggs, the hiding behavior turns off fear. But if you can’t give an animal the freedom to act naturally, then you should think about how to satisfy the emotion that motivates the behavior by giving the animal other things to do. Focus on the emotion, not the behavior.
So far, research in animal behavior agrees with the neuroscience research on emotions. A really good study on whether animals have purely behavioral needs was done with gerbils. Gerbils love to dig and tunnel, and a lot of them develop a corner-digging stereotypy when they’re around thirty days old. A stereotypy is an abnormal repetitive behavior (ARB for short), such as a lion or tiger pacing back and forth in its cage for hours on end. Pets and farm animals can develop stereotypies, too. Stereotypies are defined as abnormal behaviors that are repetitive, invariant (lions always pace the exact same path in their cages), and seemingly pointless.
An adult gerbil spends up to 30 percent of its "active time" doing stereotypic digging in the corner of its cage. That would never happen in nature, and many researchers have hypothesized that the reason captive gerbils develop stereotypic digging is that they have a biological need to dig that they can’t express inside a cage.
On the other hand, in nature gerbils don’t dig just to be digging. They dig to create underground tunnels and nests. Once they’ve hollowed out their underground home, they stop digging. Maybe what the gerbil needs is the result of the digging, not the behavior itself. A Swiss psychologist named Christoph Wiedenmayer set up an experiment to find out. He put one set of baby gerbils in a cage with dry sand they could dig in, and another set in a cage with a predug burrow system but nothing soft to dig in. The gerbils in the sand-filled box developed digging stereotypies right away, whereas none of the gerbils in the cage with the burrows did.
That shows that the motivation for a gerbil’s digging stereotypy is a need to hide inside a sheltered space, not a need to dig. The gerbil needs the emotion of feeling safe, not the action of digging. Animals don’t have purely behavioral needs, and if an animal expresses a normal behavior in an abnormal environment, its welfare may be poor. A gerbil that spends 30 percent of its time digging without being able to make a tunnel does not have good welfare.
All animals and people have the same core emotion systems in the brain. Most pet owners probably already believe this, but I find that a lot of executives, plant managers, and even some veterinarians and researchers still don’t believe that animals have emotions. The first thing I tell them is that the same psychiatric medications, such as Prozac, that work for humans also work for animals. Unless you are an expert, when you dissect a pig’s brain it’s difficult to tell the difference between the lower-down parts of the animal’s brain and the lower-down parts of a human brain. Human beings have a much bigger neocortex, but the core emotions aren’t located in the neocortex. They’re in the lower-down part of the brain.
When people are suffering mentally, they want to feel better — they want to stop having bad emotions and start having good emotions. That’s the right goal with animals, too.