A compelling opinion piece appeared in the New York Times this weekend, entitled “Dogs are people, too”. It was written by a faculty member at Emory University who has used magnetic resonance imaging to map brain activity in dogs. After successfully training 2 dogs to lay motionless for the scan, the author – Gregory Berns – found that a portion of the dog brain – the caudate nucleus – was “turned on” in response to signals that predict food (actually, what they show is that the oxygen content in blood in this part of the brain changed as the hand signal was presented as MRI cannot measure neural activity directly). As Dr. Berns says in his Opinion Piece:
In dogs, we found that activity in the caudate increased in response to hand signals indicating food. The caudate also activated to the smells of familiar humans. And in preliminary tests, it activated to the return of an owner who had momentarily stepped out of view. Do these findings prove that dogs love us? Not quite. But many of the same things that activate the human caudate, which are associated with positive emotions, also activate the dog caudate. Neuroscientists call this a functional homology, and it may be an indication of canine emotions.
He is correct that the caudate nucleus is an important part of the brain whose job it is to help us to determine the value of positive and negative stimuli (events in our environment) and to act accordingly. He correctly notes that this part of the brain, or nearby ones, often shows activation when humans are exposed to positive events. He infers, therefore, that dogs must be showing the same emotional reactions that humans are capable of and quickly pivots to the thrust of his piece:
The ability to experience positive emotions, like love and attachment, would mean that dogs have a level of sentience comparable to that of a human child. And this ability suggests a rethinking of how we treat dogs.
There are so many flaws with Dr. Berns’ argument that one hardly knows where to begin.
First, I think most of us can appreciate that anticipating food is hardly a sign of a “human-like” emotion. I have a pond with goldfish in my backyard. I always feed them first thing in the morning, usually right at sunrise. So, when the back yard lights come on in the early morning, my fish swirl to the surface and begin checking for food. They do this because their brains have learned the associations between the light coming on and food coming, and parts of their nervous system no doubt “turn on” in response to the light to trigger their feeding, just like Dr. Berns’ dog’s brain “lit up” when the hand signal for food was presented. Even insects show these kinds of learned behaviors to food cues. Showing a behavioral or brain response to a food cue (or even to the smell of a human owner) is a far cry from exhibiting a “human emotion” and does not in any way afford them the same relevancy that a human child has.
It’s not surprising that these behaviors are present in evolutionarily old animals because learning to predict food is a crucial behavior for survival in all species. It’s therefore also not surprising that evolutionarily old parts of the brain are used for these abilities. There are in fact many parts of the brain specialized to a great degree in human beings, giving us our unique abilities. The caudate nucleus is explicitly not one of them. Brain regions akin to the caudate are found in birds, lizards and fish. Because it is such an evolutionarily old part of the brain, it’s not surprising that its function is also quite old.
Second, Dr. Berns claims knowledge of scientific literature to support his point of view. He says that he can infer emotion in the dog because it’s caudate nucleus is turned on. In his post, he notes that:
In humans, the caudate plays a key role in the anticipation of things we enjoy, like food, love and money. But can we flip this association around and infer what a person is thinking just by measuring caudate activity? Because of the overwhelming complexity of how different parts of the brain are connected to one another, it is not usually possible to pin a single cognitive function or emotion to a single brain region.
But the caudate may be an exception. Specific parts of the caudate stand out for their consistent activation to many things that humans enjoy. Caudate activation is so consistent that under the right circumstances, it can predict our preferences for food, music and even beauty.
What he fails to tell you, of course, is that the same parts of the human brain are engaged by anticipating or experience very unpleasant events, like an electrical shock. In that sense, how could you possible infer the presence of a positive emotion from activation of this part of the brain? You can’t, which is why neuroscientists have called out this flawed logic, referred to as reverse inference.
Third, even if he was right and dogs did experience joy when food was given, it hardly implies they have human-like emotions – or more importantly – human-like reason and cognition, abilities that lead to our moral relevancy and moral decision-making.
I am a long-time dog owner and lover. Like most dog owners who have lost a dog at some point, I understand acutely the value of a dog’s life, as well as their unique and joyous being. But what is so wonderful about dogs is that they are dogs, and not people. Their whimsy, playfulness and unconditional affection is what brings us joy, and they are capable of these things because they are dogs.
In his OpEd, Dr. Berns trivializes science, the powerful technologies we use to understand the brain and dogs themselves. When science is twisted and misused in this way, we all lose.