You Animal You

A couple of recent posts have generated some lively discussions, and some of them have led to the nature versus nurture debate. I have been arguing that we come with many of our basic emotions pre-wired, and that it is only the relatively new emergence of malleable cognitive faculties that gives us the chance to change the outcome of situations that would otherwise go down as instinctive responses to external stimuli. Basically, the complexities of cognition and consciousness provide us with free will. Some, however, do not agree. They believe that the hard-wired parts of our minds are limited to the autonomic stuff and the basic survival skills (fight or flight, etc.). They think that the only way I can be right is if humans are robots, robots that were designed. I've made my case in comments and will probably attempt to summarize once the dust settles, but I think there's some value in introducing some basic cognitive science into the picture. What follows is taken almost directly from Chapter 3 of my book.

Contrary to what many people like to believe, no need to believe, humans are not cosmically special. We are animals, not uber-rulers of a vast universe. Yes, we are sophisticated and capable of staggering feats of intelligence, but we are also consistently guilty of acts of passion that mirror the instinctive exploits of our animal cousins. What can we say? It’s in our genes. We all have the same basic genetic framework. The same four letter DNA alphabet (A, T, G, and C) serves as the underlying scaffold for all life on earth. Strands of DNA form genes. Throughout the history of life on this planet, genes have given rise to new organisms that were incrementally different from the ones that came before. However, new organisms were not created from scratch every time. Their designs were built upon designs that have worked well all along. This is why it makes sense that we share 98% of our DNA with chimpanzees, but only 90% with mice. This notion of conservation of design is starkly evident when it comes to the design of the human mind.

The vertebrate brain is divided into three major divisions: the hindbrain, midbrain, and forebrain. It turns out that the structure and function of the hindbrain and midbrain in humans are very similar to what is seen in reptiles, birds, and other mammals. All vertebrates have basically the same organization in the spinal cord, brain stem, thalamus, and cerebellum. That goes for rats, lizards, chimps, and humans. To go even further, we know that the same neurochemicals found in the human brain are also found in the nervous systems of leeches and worms, as well as reptiles, birds, and other mammals. Of course, this is not to say that we have the same minds as other animals. Humans are certainly endowed with mental structures and capabilities that far exceed those of any other animals on our planet. The point, however, is that the aspects we share with other animals are playing a leading role in our everyday lives, whether we know it or not. A light exploration of the architecture of the human mind will give us a feel for this.

The fact that we share our emotional infrastructure with other animals has a profound implication on how we experience life and on our search for truth. Consider the following diagram.



It depicts the pathway from an emotional stimulus to a bodily response in the brain. The first thing that happens is the emotional stimulus (say spotting a bear when you’re walking in the woods) sends a signal to the thalamus. The thalamus sends the signal to both the amygdala and the cerebral cortex. The amygdala (a brain structure known to be critical in the execution of basic emotional behavior) is responsible for issuing the response as quickly as possible to prepare you for action. The thalamus to amygdala loop constitutes what we’ll call the emotional pathway. The response it issues manifests itself not only in the immediate body response (such as elevating your heart, causing you to freeze, and preparing your muscles to act), but also in a signal to the cerebral cortex. The cerebral cortex has the luxury of taking its time to receive the signals both from the thalamus and from the amygdala. It also sends signals back down to the amygdala to be processed along with incoming information from the thalamus. So, the conscious emotional experience is separate and comes after the emotional response. The emotional response is what we share with all vertebrates. The emotional experience is reserved for those of us with consciousness. The jury is out as to exactly where that line is drawn, and I won’t dare hazard a guess. But I’d like to believe my dog is conscious. In any case, there are some points to be made about this arrangement between emotions and cognition.

In terms of the brain, there is a “low road” and “high road” when it comes to mentally processing an external stimulus. The low road is the evolutionarily old route. It corresponds to the pathway from the stimulus to the thalamus to the amygdala to the bodily response. This is the basic flow of what we can think of as emotional programs that take place in what is known as the emotional unconscious. It was designed by evolution to produce survival-enhancing responses to stimuli in the real world. This is really the point of the emotions we share with other animals – they are our rapid-response system. The high road, on the other hand, is the evolutionary new kid on the block. It corresponds to the pathway from the emotional stimulus to the thalamus to the cerebral cortex to the amygdala (and back to the cerebral cortex in a loop) to the bodily response. The cerebral cortex is, in a sense, where the cognitive processing happens. While the stimulus is eliciting a response on the “low road,” the cerebral cortex is assimilating both the stimulus and the emotional response into something that can be considered in a larger context. There are two aspects of this arrangement that have implications on our everyday lives.

The first is the notion that emotional processing inhibits cognition. Look back at the diagram and notice how the brain’s cognitive and emotional equipment are connected to each other. As crude as it is (I hear publishers have editors for this kind of thing), the arrangement is deliberate. The emotional low road is connected more closely to the nervous system, and therefore to the environment, than the cognitive high road. This is because, in evolutionary terms, it is much older. It is the part of the brain that we share with other mammals. In a way, our emotions are our brain’s first line of defense. The cognitive loop is “above” the emotional loop in the sense that all stimuli pass through the emotions en route to the cerebral cortex. The thalamus to amygdala loop, therefore, gets first right of refusal in terms of mounting a response to any given stimulus. It gets to decide whether and how to react to a stimulus before the high road is ever involved. This is important because, when the emotions take charge, there seems to be little room for cognition. It’s that simple. And there are plenty of examples in everyday life to prove it.

Ask almost any first time mother of an infant this question. When your baby cries, how easy it for you to think clearly? My straw poll of some well-educated young mothers yielded a pretty much unanimous response, “When my baby cries, I become completely stupid.” They went on to explain that the sound of their babies' crying brought out feelings of anguish to fix the situation. Of course, as the children get older, this effect diminishes. However, the anguish is perfectly understandable. Some of the most basic emotional functions exist to ensure the wellbeing of offspring. They most directly serve the most gigantic of biological imperatives – the perpetuation of genes. It is, therefore, no surprise that the sound of one’s own baby's crying elicits a very strong emotional response. (This was originally written before my child was born. I can now personally attest to this.) What is surprising, however, is how much our emotions are involved in our thought processes.

The second implication of the brain's organization has to do with the congnition versus emotion question. The fact that all cognitive processing happens after emotional processing means that we can’t really be sure about the state of our processing system for any given stimulus (or situation). We can’t be sure how much of the processing that is going on is emotional versus cognitive. In other words, how much of how we are evaluating the world and responding to it is because of what we’re thinking versus what we’re feeling? As much as we would all like to say that we can usually answer that question accurately, the fact is that we really can’t. The odds are against us – for two reasons.

For one thing, emotional processing happens much faster than cognitive processing. Consider the fact that emotions evolved to deal with life and death situations. They facilitate split-second responses when necessary. Cognitive processes, however, are in no hurry. If something is important enough for you to need to respond almost automatically, you can bet there is a basic emotion mediating it. So, emotions are involved first, and they work fast. In the real world, this means that by the time we get around to thinking about something, there’s no telling how much emotional processing has occurred. We can all recall situations where we have reacted emotionally, but denied it vehemently, only to come to our senses and apologize later.

The odds are also against us because of the sheer magnitude of tasks handled by emotions versus those handled by cognition. The brain’s cognitive faculties are evolutionarily new, and they have been built on top of the ancestral emotional infrastructure we share with other animals. We are capable of handling tasks, such as finding food and shelter and responding to threats, with our emotions entirely. Whether we like it or not, the fact is that our animalistic emotions are involved in our daily lives a lot more than we think they are. They’re always on duty; that’s how the brain is wired.

So what does all this have to do with the nature versus nurture argument? It establishes the scientific basis for the idea that what we observe in nature (the phenotype) is the result of a combination of both forces - genes and the environment. More importantly, put this together with the ideas that we share much of our emotional infrastructure with animals and that other animals (primates, big cats, elephants, etc.) have basic emotions that lead to seeking status, anger, jealousy, and so on, but do not have our cognitive faculties, and you can reasonably conclude that a big part of our emotional repetoire is hard-wired. This is not to say that we are doomed to a predetermined existence. The diagram depicted shows quite clearly how the cognitive loop feeds back into the emotional loop, which means that even the most genetically controlled systems can be cognitively manipulated. That really is the scientific basis for the notion of enlightening the caveman in all of us. Am I getting through to you dualists out there?

Footnotes -
1. Some of the info on the wiring of the brain comes from Joseph LeDoux’s The Emotional Brain: The Mysterious Underpinnings of Emotional Life (Touchstone, 1996).
2. Aspects of the discussion on the evolutionary origins of emotion come from Descartes' Error : Emotion, Reason, and the Human Brain by Antonio Damasio (Avon Books, 1994).