Of course, it's simple: You ask him. Therein lies the problem with animal emotions. Not only can we not experience what they experience emotionally, we can't ask them what they're feeling. However, we can exercise a little common sense.
With the rise of ethology -- the study of animal behavior -- scientists began to allow for what actually causes behavior: emotion. Behavior problems are the number -- one cause of preventable death -- euthanasia for dogs under three years of age in the United States. Dogs have emotions. Emotions cause them to behave in certain ways. We must understand the source and catalysts of emotion before we can hope to deal successfully with behavioral problems that result from it.
Dr. McConnell explains that every emotional experience includes changes in the body, changes in expression, and thoughts or feelings that go along with them. The scenario: A man is pointing a gun at Nick as I stand next to him. The threat is real and my body floods with norepinephrine, a stress hormone that affects the part of the brain controlling action; I prepare for "fight or flight." My expression changes, my eyes widen, and my pupils dilate. I'm thinking to myself, Oh, God, Nick is going to get shot. I reach out and pull Nick to safety. This simple short scene illustrates that emotions do precipitate a range of action, from subtle eye gestures to racing heartbeats to sweeping body movements. Researchers used to believe that as our senses registered something—a charging bear, for example—we would experience an emotion, and that emotion would cause changes in our body, expression, and thoughts. Some experts now speculate that that theory was backward, believing instead that as we register sensory data that causes changes to our body and mind, we then feel the fear. I see a man with a gun turn toward my beloved dog, my body chemistry changes, my eyes widen in horror, and I think, Oh, no! Only after all of that do I feel fear.
It is counterintuitive to claim that emotion doesn't affect animals. After all, how long would a species survive without being able to experience fear? More and more experts are starting to agree. Marc Bekoff, professor emeritus of biology at the University of Colorado–Boulder, says in his book, "The Emotional Lives of Animals:" "It is bad biology to argue against the existence of animal emotions."
Darwin unquestionably believed that animals have emotions, and many experts still concur that what Darwin termed the "universal emotions" of fear, anger, disgust, surprise, sadness, and happiness are indeed the primary emotions. These are the emotions that require no conscious thought to experience, since they are born with us, hardwired into our systems.
The "triune model" from neurologist Paul MacLean suggests that we have three separate brains representing different levels of evolution. The lowest level is the reptilian brain, shared by everything from snakes and fish on up the evolutionary ladder to the very top. In addition, mammals have a paleomammalian, or limbic, brain. Finally, the more highly evolved species like man and dog have a top level known as the cerebral cortex, the thinking part of the brain that is far larger in man than in any other species. Though there may be multiple "emotion systems" in an individual's brain, primary emotions are connected to the limbic system and thus to the limbic brain shared by all mammals.