The Psychobiology of Emotions

This page discusses the underlying psychobiology of emotions or feelings and their importance.

What are emotions?

Emotions are feeling states. They are the affect side of consciousness. They have both psychic and physiological dimensions. They are subjective but are readily communicated to others.

Feelings are neither good nor bad

Our feelings are just our feelings. Not good, not bad, just feelings. We have little affect on how we feel about something. They are so primal, so fundamental to what makes us human. They go way back in vertebrate evolution, especially mammals.

While how we feel about something is neither good nor bad, what we do about those feelings can be good or bad. This is where the good old brain, actually the cerebral hemispheres, comes into play. It has control over our behavior, which is what we do (and say).

There is a whole branch of therapy, called Cognitive Therapy, that argues that our thoughts control our feelings. I have real problems with this premise as emotions were here long before our large cerebral cortex (see evolution discussion below). Yes, we can affect our emotions through rational arguments and reason. But let's not put the horse before the cart (Somehow this seems appropo for this website--the horse-cart analogy.) Emotions are primal, basic. Rational, logical thought override is only a very recent evolutionary addition.

What are the basic emotions?

Depending on which authority you read, there are seven basic emotions: anger, fear, sadness, happiness, emotional pain, shame/guilt, and loneliness.

Some authors would also include surprise as an emotion. This is related to the startle response. Or, as I discuss in the Wild Ride, being "spooked", in the case of Mustang Sally.

Emotions are not all-or-none. They usually occupy a continuum. You can be a little sad or a lot sad, a little angry or a lot angry, etc., or anywhere in between.

One of the tricks of the trade in therapy is to have the client self-rate how strong their feelings are. I usually use a 0-10 scale, where "0" is no sadness, anger, etc. and "10" is the maximum of experiencing that emotion.

More complex emotions consists of mixes of these basic emotions and various gradations of them on their continuum. Frustration, for example, may be a mix of anger and sadness.

You can feel more than one emotion at the same time. You can feel both sad and happy for example.

While most of these basic emotions are self-evident for most of us, I want to say a few words about a couple of them...

Anger and fear

Anger and fear are the emotions of the flight-or-fight response, the most fundamental of vertebrate survival tools--and many invertebrates too. Fear is to flight as anger is to fight. They have a specific part of the brain, an ancient part of the brain, the amygdala, buried deep the ancient midbrain, that regulates them.

Diseases or accidents that damage the amygdala result in a loss of fear and anger. Sounds good, no? No, is right. These individuals have a significantly lowered chance of survival.

Shame and guilt

These are similar but different from the therapeutic standpoint. Shame is something imposed from the outside by others for something you have little or no control over. Guilt is a feeling of regret or remorse for something you have done. You had control over this one (usually) but are feeling bad about the choice you made.


n-Dimensional Emotional Hyperspace

A way of conceptualizing emotions is in terms of an n-dimensional emotional hyperspace, where n is the number of basic or primary emotions. This model helps us understand our comfort zone and personal growth. Here is a link to a page that discusses this concept and its here

Evolution of emotions

Emotions began in primitive protozoans (mobile, single-cell, microscopic critters) as a simple approach-avoidance response. You moved toward something that was "good" (food, mate, light, etc.) and away from things that were "bad" for you (e.g. predators, toxic compounds, darkness, etc.) This movement is referred to as "taxis". Life of a protozoan is pretty basic so they don't need a complex emotion system. Where would they house it anyway?

Even plants might be said to have their own primitive "emotions"--their own approach-avoidance system. The "move" by growth though. This growth is called "trophism". Plant leaves and stems grow toward light--something called positive photrophism. Whereas roots are negatively phototrophic--they grow away from the light.

As organisms became more complex and mobile (multicellular, brains, legs, that sort of stuff), they needed a larger range of emotional responses to cope with the more complex enviornments they encountered. Those that had a wider range of emotions survived and reproduced better.

Why do we have emotions?

Remember Mr. Spock of Star Trek? His totally logical mind devoid of emotions? If having no emotions were such a great thing, then why do mammals as well have so many of them. Why are we not more like Mr. Spock? In short, and as indicated above, Mr. Spock would have been at a selective disadvantage in terms of his survival, and lets not even go there in terms of reproduction.

Better survival and reproduction

Survival and reproduction are the two evolutionary imperatives. You don't do these, and both of them, you and your genes loose in the evolutionary game. So there was natural selection for more complex emotion systems. But more complex emotion systems required more complex brains or central nervous systems. Emotions confer a selective advantage for organisms that have them. Emotions help us to survive and reproduce.

Fear and anger are probably the most primitive of the emotions because they are coupled to the flight-or-fight response.

Quick read on the environment

Emotions give an organism a quick assessment of his environment. No thought required. Go with your gut feeling, etc.

If you are a frog or lizard, not a lot to "think" with anyway. About all these critters, the lower vertebrates, sharks, fish, amphibians, and reptiles, can do it seems is flight-or-fight stuff, fear and anger.

Of course they can get affectionate too. But that has more to do with hormones, pheromones, and mating than emotions per se.

Help us make decisions

Emotions help us make decisions. It is hard to choose between alternatives if you do not have any emotion toward them one way or the other. Hamburger or hot dog? How do you choose? Does one make you happier than the other? Probably.

Darwin's studies

Charles Darwin, the father of evolutionary theory, was one of the earliest pioneers to systematically study emotions. He looked at emotions in other mammals and across cultures. His findings were published in his book, The expression of the emotions in man and animals, in 1898.

In general he found that other mammals use similar muscles in their face and body to express many of the same emotions as humans. Across cultures, the same muscles and emotions were seen. So emotions seem  universal in mammals.

Emotions and the Brain

The Triune Brain

This gets us to what has been called the triune brain (coming soon). The triune brain distinguishes the reptilian brain, the mammalian brain, and the the neo-mammalian brain. The latter, found only in man and perhaps the higher primates, is characterized by the greatly expanded cerebral cortex, more complex cross-connections between the two cerebral hemispheres of the cortices, and an expanded limbic system.


Limbic system

It is the limbic system that houses and enables our complex emotional system. It is in a sense our "emotional brain". Derived from the olfactory (smell) parts of the brain's temporal lobe, it also explains why smells are so linked to our emotions and, consequently, why and how aromatherapy works. This is why aromas or smells can elicit such emotional responses. The amygdala is part of the limbic system and has to do with our emotion of fear.

Right and Left Brain

EEG studies have indicated that the right frontal lobe of the cortex controls negative emotions like depression, fear, shame, etc., while the left side, positive emotions. Shy or inhibited children more right frontal activity and more left frontal activity in bold or uninhibited children.

Molecules of Emotion

Candace Pert in her great book, Molecules Of Emotion: The Science Behind Mind-Body Medicine, discusses her discovery of endorphins. These natural opiates of the body are our feel-good molecules that connect body to mind in a complex information network that we can refer to as the body-mind. They are neuropeptides, short strings of amino acids that act as neurotransmitters, transmitting information between neurons and cells.(See discussion in "Neruotransmitters", coming soon)

Her pioneering work discovered opiate receptors that lie on the neuron's outer membrane. Many more of these endorphins and neuropeptides have since been identified along with their receptors. These receptor-neuropeptide systems along with other such systems. explains the body-mind experience of emotions. 

Genes of emotions

The Human Genome project has enabled us to to identify several genes associated with emotions. There are genes that have been identified that affect depression, anxiety, thrill seeking, and addiction, for example. (See Living with Our Genes: Why They Matter More Than You Think.)

We know from other genetic studies that many mental disorders have a large genetic (hereditary) component, e.g. depression, anxiety, bi-polar, Asperger's, schizophrenia, etc.

Let us talk about one gene that has been identified that affects emotions and is related to novelty or thrill-seeking. We will discussed other genes related to emotions in other sections. Genes that affect anxiety and depression have also been identified and is discussed more in those sections.

The thrill-seeking gene

Dopamine is our "feel good" neurotransmitter. It affects is our emotion of happiness.

As discussed in our Depression page, it along with serotonin and norepinephrine (a.k.a. adrenalin) in proper balance, are important for maintaining mood. There is a gene that codes for dopamine and another that codes for its receptor. But, we want to briefly discuss an associated gene that affects what stimulates the release of dopamine in our brains, the D4DR gene. First, back to dopamine...


Dopamine energizes or motivates people to seek something that feels good. In our primitive organism model mentioned above, it energizes our critter to approach something that "feels" good, e.g. food, light, a sex, etc.

There are a group of cells deep within the brain in a region called nucleus accumbens that are especially rich in neurons that produce and respond to dopamine. This is sort of the brain's "G-spot" for those that know something about this from human sexuality.

Biochemically, dopamine is composed of a modified single amino acid. So it is in a class of neurotransmitters called monoamines. These are a group of neurotransmitters that are involved in affecting personality, depression, drugs and alcohol, aggression, eating, and sex.


Briefly each neurotransmitter has its own receptor. The two of them, neurotransmitter and receptor fit together sort of like a lock and key. The neurotransmitter is the key and the receptor is the lock. There are separate genes that code for each receptor. Receptors are proteins. Our cells' surfaces are lined my a huge array of these receptors. This is discussed more fully on the "Neurotransmitters" page (coming soon).

Mice without dopamine

To give you an idea of what dopamine does in terms of energizing or motivating behaviors, in one experiment mice were genetically engineered so that they would not have dopamine. All they wanted to do was to lay around. They were not motivated even to eat. When they were injected with L-Dopa, a replacement for the dopamine they could not produce, they quickly recovered their interest in eating, drinking, and moving around.

In humans

Dopamine deficiency in humans is what leads to Parkinson's disease and is caused by a degeneration in cells in the substania niagra that also lie deep in the brain. In addition to the physical movements affected by Parkinson's, there are accompanying changes in personality caused by the dopamine deficiency. Most notably affected was the trait of novelty seeking.

The DN4R gene

This gene codes for one of the several dopamine receptors. There are several versions (alleles) of the gene found in the general population. It is the long version, which has an elongated number of amino acids in the middle of the receptor protein. People with this long version are what can be called "thrill seekers".

Recall that for any gene (a.k.a. locus) we carry two alleles. One we get from our mother and the other from our father. If we get the same version of the gene (allele), we are said to be homozygous for that gene. If we get different alleles, we are heterozygous.

People that are homozygous for the long version allele rate hight on thrill seeking. In order to get enough dopamine affect in their brains, they have to be involved in intense thrill activities such as sky diving, racing, mountain climbing, bull riding, etc. Only when engaged in such activities do they feel really alive. They just can't seem to get enough dopamine otherwise.

The long version of the D4DR gene protein does not bind with dopamine as well as the shorter versions. So it takes more dopamine to have the same affect as people with the shorter version.

Addicts have a similar problem. In this case, however, the drug has decreased the number of dopamine receptors available. More about this under Addictions (coming soon).

This gene is highly expressed in the limbic portion of the brain, our emotional center.

Hot love

Just as an interesting aside to this story is the emotions that surround infatuation. There is a dopamine high produced in the early stages of many relationships that is addictive as a result. As time goes on however, and if the relationship continues, the dopamine level drops off. This is about the two-year point at a maximum (usually). At which time the relationship must "mature" into a new kind of relationship.

This is one of the reason we see such a high frequency of divorces, separations, and breakups around the 1-2 year point. The dopamine high has worn off.

This is also probably why in ancient and indigenous societies we see breakups of the "marriage" between the 2-4 year mark: two years for the dopamine high, and four years for weaning from breast feeding of the young.



Neurogenesis and Healing

Addiction and the Teen Brain

The Triune Brain

State-Dependent Memory, Learning, and Behaviors and Trauma

Basic Genetics Series

Nature and Mind

  • Clinical Psychobiology