Emotions and the triune brain

The work of Dr. Paul MacLean, in identifying the parts and functions of man’s brain, appears to offer a neurological explanation for the effectiveness of bonding.  Dr. MacLean, former chief of the Laboratory of Brain Evolution and Behavior at the National Institutes of Mental Health, describes a triune brain containing three parts. The first, most primitive part, is the basal ganglia. The next part is the surrounding limbic system, or the emotional brain. Last is the neocortex, which is the logical, thinking part of the human brain.

MacLean and others view the neocortex as the primary locus of reason, and it could be called the ‘rational brain’. The limbic system is the primary site of emotion, such as love, pleasure, anger, fear, and pain, and could be called the ’emotional brain’. The basal ganglia controls and coordinates movement and related functions, and could be called the primitive brain.’ MacLean sees the site of our emotions as located in the limbic system, that part of the human brain that is actually a relic of the old mammalian brain!

In other words, the human brain appears to exist on three levels. A primitive, visceral brain, an emotional brain from the limbic system, and a rational brain which came with the development of the neocortex. What is of particular interest here is that the brain was not transformed into a single integrated new unit, as fins in fish became limbs in man. Rather, nature superimposed each new unit upon the other, so that we function with three interrelated but distinct brain systems, each with its own unique patterns and needs.

MacLean’s theory provides interesting insights into the complexities of human behavior. He postulates that by analogy “it’s as if the brain has acquired three drivers, all seated up front and all of different minds!” In other words, it’s as if the human system were being driven by an alligator, a gorilla, and a computer! What is of further interest is that we now know that under stress or in a state of anticipated danger, the more primitive levels of the brain take precedence or control over the higher portions by distorting the input of information.

To picture this, we can imagine the nerve cells of the primitive brain as stone-age cliff dwellers finding shelter in a honeycomb of caves and tunnels. The basal ganglia tends to be a slave to routine, precedent and ritual. “In human activities,” states MacLean, “expressions of the primitive brain are found in slavish conformance to routine and old ways of doing things, personal day-today ritual and superstitious acts, obeisance to precedent (as in legal and other matters), ceremonial reenactment, responding to partial representations, whether alive or inanimate, and all manner of deception.”

According to MacLean, the primitive needs dictated by the visceral brain include a sense of safety and territoriality, and corresponds with the human need for order, routine and regularity as a home base from which to explore. To the extent that these primary needs are denied, so can they become more insistent. Instincts preserve a perfect memory for what their ancestors learned over millions of years, but the primitive brain is poorly equipped for learning to cope with new situations. MacLean postulates that without a basic sense of security, man is unlikely to extend his learnings or his potential for change beyond the survival or primitive level. (It is possible that some of the people we now label dumb or slow or stubborn are simply still trying to determine if they are safe!)

It is in the limbic brain that we find the beginning of social groups, mating, breeding, flocking and migration formation. Behavior associated with the limbic system has to do with the experience of bearing dependent young, which requires maternal bonding and allows for a period of play and exploration before getting down to the more serious business of survival and procreation of the species. Here then lie the roots of family structures and the differentiated sex roles that make possible the lengthy period of child-­rearing typical of human beings. We also find here communication through sound. The most primitive sound is the wail of the nursling for its mother.

In terms of location, the limbic system surrounds the brain stem and is found in the brains of all people. Through the hypothalamus, it has a much more direct influence than the neocortex on the body’s visceral and glandular functions. It wraps around the hypothalamus, where certain pleasure and pain centers are located and thus pain in the limbic system is conveyed to the pituitary gland, which is the master gland of the body that orchestrates body chemistry through the release of hormones. Thus, sustained emotional stress often produces hormonal imbalances that not only affect bodily functions, but can also suppress the body’s immune system. Thus, emotionally caused suppression of the immune system is now viewed as a significant factor in the development of cancer as well as other diseases. Many psychologists have come to believe that cognition cannot be dealt with separately from emotions, as energy repressed in the emotional part of the brain will seek exits through other parts of the body and can result in disease. In other words, if emotions are not brought into conscious awareness and fully expressed through words or sounds, the energy tied up in them will seek other channels for expression, including illness, depression, or acting-out behavior.

Clinical and experimental findings over the past forty years indicate that the limbic brain evaluates sensory information in terms of emotions that guide behavior required for preservation of the individual and the species. In responding to information about pain and pleasure, the limbic brain is primarily involved in the experience and expression of emotion. MacLean comments: “When we think of how we evaluate the importance of things, nothing could be more fundamental than the realization that the limbic system has the capacity to generate strong feelings of conviction that we attach to our beliefs, regardless of whether they are true or false.”

MacLean theorizes that signals from the outside world made it difficult for the organism to make clearly reasoned decisions for survival. Nature remedied this situation by developing the third lobe of the brain, the neo-cortex, or rational mind. This newcomer to the human brain system is viewed as the mother of invention and preservation of ideas. Receiving signals primarily from the eyes, cars, and body wall, the neocortex focuses on material objects outside the organism and functions somewhat like a coldly reasoning, heartless computer.

In laboratory experiments with rats and hamsters, co-workers found that when the neocortex was damaged, animals were still able to mate, breed and rear young, and were almost indistinguishable from normal animals in a variety of psychological tests.  In experiments with other animals, when basal ganglia and the limbic system were destroyed, although the neocortex was left intact, almost everything typical of animal behavior ceased. These experiments, together with certain findings on patients with brain disease, indicate that the “neural substrata for the basic personality and the organized expression of behavior” is provided by the primitive brain and the limbic system, and not by the rational thinking brain!

The structure of the human brain is such that no information reaches the neocortex without first passing through the limbic system, where the emotions originate. Emotions color that information and determine how much attention will be paid to it. In this way, emotional needs deeply influence thinking and cognition. In addition, emotions have been found to be deeply implicated in the operation of long term memory. When our emotions are sufficiently aroused, we shut out the cerebral cortex and are caught in their grip, fanatic in our insistence on the logic of our thinking. We communicate emotions and signal both danger and pleasure through sounds and gestures, which suggests that communication and sharing of feelings are critical to the survival of the early mammal in each of us. However, for positive learning to occur and to be available for later use, (through memory), the environment must be safe, and we must be able to trust. Otherwise, we revert to the more primitive response of self-protection!

Paul MacLean’s model of the triune brain helps to explain the behavioral dominance of the more primitive parts of the brain, which prepared to step in and take over if needs are not met. Thus, we see regressive behavior in formerly `rational’, well-functioning people when their basic needs and security are threatened. Many times, in structured learning, we fall into the trap of trying to separate the cerebral cortex from both the limbic system and the visceral brain, but this merely produces fragmented thinking, confusion and even disease. It is apparent that humans can’t be reasoned out of their basic needs! If their needs are met, they are then free to explore and to be creative. It is of interest to remember that the word ‘primitive’ derives from the word ‘primary’, which means ‘first’!

MacLean’s theories about the triune brain provide interesting insights into the clinical work of Daniel Casriel, MD, and support Casriel’s theories about the logic of emotion as it affects human behavior, the nature of pain and pleasure, and the continuing need for bonding — physical closeness in an emotionally open, sharing and safe environment. Casriel believes that our biologically based need for bonding, and our need to discharge survival-­based emotions of pain, fear and anger (which can be met full-measure through screaming), provides the missing link between primitive and modern man.

In our culture, we are rarely able to fulfill our biologically based needs for physical and emotional contact (in words, sounds, gestures and touch) in a climate of predictable and trusting closeness, as so many people in our culture are “weary, leery, teary,” hopeless and despairing. Casriel sees Western man as being “phobic of intimacy,” while he sees intimacy or bonding as a basic biological need inherited from our primitive ancestors.

MacLean’s theories about the biological needs of the basal ganglia and the limbic system help to explain the success of the “Bonding Workshop.” This approach emphasizes the restructuring of an individual’s emotions, behavior, and attitudes (emotionally-laden thought patterns) and encompasses the needs of all parts of the brain. By teaching the individual how to get his or her basic need for bonding met within a supportive group, and how to ventilate pain-related emotions of fear and anger, Casriel effectively encourages gratification of the needs of the visceral and limbic parts of the brain, freeing the neocortex to absorb new learnings. Rather than fear our instincts, emotions, and bodies and view them as the seat of neurosis, illness, or lack of control, we now know we must integrate the needs of the brain’s three parts to release our potential for conscious control, for emotional and physical health, and for greater depth of understanding.


If the needs of the triune brain remain unrecognized and unfulfilled by the adult, then stress, distress and disease result. When we fulfill our physical and emotional needs, we feel whole and “at one” with ourselves. As we recognize the complexity of our own nature, we can respond to it knowledgeably and develop the skills necessary for sustaining ourselves in a state of physical and emotional well-being. Experiential training and immersion in bonding provides an excellent media for developing such understanding and learning these essential skills.

~ Lori Heyman Gordon