It is a beautiful day outside, the person you care about just told you they feel the same way, you paid all your bills and still have money left over, and you finished all your work on time, yet you are still in a very crabby mood. Or, it is an awful day out, you just failed an exam, you have a ton of work to finish in too little time, and you were just dumped, still you have a feeling of well-being that you cannot change. We have all been there, our emotions seem to have a mind of their own and we do not know why we are feeling what we are feeling. Philosophers, psychologists, and science fiction writers have been debating the usefulness of emotions for centuries, still we continue to experience them and deal with them as part of our existence as human beings. Neurobiologists have preferred to take the tactic of looking at emotions as something we experience, thus something that should be studied. This tactic has led to some interesting evidence in terms of the usefulness of emotion in our everyday life. Some have found that experiencing the variety of feelings that we do might help in our ability to remember things and in learning about the world around us. If it is the case that emotional information does help us when we remember things and learn, then how do emotions work in the brain? There have been found to be some key structures, each playing a role in the way we experience emotions and what kind of moods are experienced. Still, with all of this information, we still have emotions that we cannot explain given our everyday experience. The increased understanding of neurobiology that we have can be used to explain why we feel what we do, even when the external world cannot.
It had long been thought that any research into emotion was a waste of good research efforts. There were many reasons for this, but primarily the idea was that emotions were not scientific enough for science. As time and methods have changed, so has that attitude and now emotions are looked at with slightly more respect and less apprehension about their not being rational. (1) This change in attitude has led to people finding that emotions might actually lead to somewhat useful things. One researcher has found that the emotional content of stimuli can influence our ability to remember the stimuli in future. He found that when he did PET scans on people, activity in the amygdala when the people were watching highly emotion arousing films was correlated with their long-term retention of the material. Activity in the same area of the brain when watching something that did not arouse emotions did not correlate significantly with memory of the material. He had also found that when certain chemical functioning of the amygdala was blocked, memory was impaired in people, while amnesiacs with this area intact had a greater ability for memories with emotional content (2). Another case involves a businessman who had a tumor removed. While the tumor's damage did not affect the man's intelligence, after the removal, he can no longer make good decisions. He repeatedly makes bad ones and they do not bother him. He realizes that the decisions are bad, but cannot change his behavior when making them. It was found when studying him later that the area damaged had been parts of the pre-frontal cortex. While he did lose his ability to plan in a small way, he also lost his ability to experience emotion to a great degree. The doctors treating him believe that it is the ability to experience emotion that is causing his decision making problems. When a decision is made that is either bad or good there is an emotional content associated with the decision. That emotional content, whether or not it is rational affects how we make a similar decision in the future. The fact that this person has lost the ability to feel emotions means that he makes decisions based on his reason alone, losing a component of the decision making process. That component is what allows us to see past the dry pros and cons of an issue and into the grayer areas of what is truly important to us and those around us (3). Through this evidence there is further reason to study the effects of emotion on our everyday life. Emotions play a bigger role then the everyday ups and downs we experience, they affect how we process all of our information which can have long-term repercussions in our lives.
As has been shown by some of evidence already presented the amygdala probably plays a big role in emotion and how we experience it. It has been implicated in experiencing strong emotions, specifically fear. When it is removed from animals, extreme passivity ensues. When it is electrically stimulated, extreme aggressiveness is shown by the animals. Evidence like this has led people to think that this structure is what allows us to complete the fight or flight response that is so important for animal survival. The hippocampus, because of its influence on memory, also probably plays a role in emotion. If this structure is removed animals have trouble forming long-term memories. The hypothalamus also may have something to do with emotion. Specifically because it has something to do with the sympathetic nervous system expression of emotion. (4) We all have had the racing pulse, or sweaty palms when nervous. In fact it has been suggested that it is the experience of this physical stimuli that causes emotion. By feeling the racing pulse and sweaty palms we identify the sum total of the sensations as nervousness. (5) However, it has been shown by tetraplegics, who have little sensation below the neck that they still experience emotion. This lends support to the idea that it is more of mind to body relationship and not the other way around. (1) The prefrontal area of the brain is what plays a large role in humans ability to feel emotion and use it in decision making processes. It is why a Modest Proposal is not so modest and causes revulsion in the reader. This area is the largest in humans and may allow for a more rational analysis of something which does not really lend itself to rational thinking. (4)
Given all of this information, we still have not explained why the situation at the beginning of the paper exists in our everyday lives. By explaining emotion as something that is useful and something that has definite neurobiological basis, we are, however, closer to coming up with some of the reasons that might explain the situation mentioned at the beginning of this paper. It has already been shown that there are certain areas of the brain that are implicated in the experience and control of emotion. While no one area of the brain is solely responsible for all of the emotion that a person experience, the areas do interact with each to help to form the experiences we call emotions. Since this is the case we can safely suppose that these areas of the brain are made up of neurons that fire and release chemicals. Emotion is, like all other things that we experience, is merely a pattern of activity in the brain and body. With that being the way it is, it is reasonable to also expect this system to have some random firing in it. It has been shown that neurons fire at various times and not always with input causing them to fire. That random firing could start a pattern of activation which would cause the feeling of certain emotions. That random firing could explain why we have unexplainable emotions. Chemical functioning could also play a part. Having excess or too little of certain neurochemicals could very logically lead to the feelings that seem to defy all of our explanations. Sleep and diet have been implicated in our balance of neurochemicals.
While the situation at the beginning of the paper is a very real one, there are times when you can talk yourself out of the emotions that you are experiencing. The evidence presented would lead one to think that our emotions are more in control of us than the other way around. Given certain inputs the brain will respond with certain patterns of activity, having some variance but pretty consistent, which would cause us to experience certain emotions. Then there is random firing which would cause us to have emotions that we cannot explain, but feel nonetheless. However, we can cause changes in our own neurochemistry. It has been found in studies of heart-rate, which can be used to determine experience of emotion, people can voluntarily control their heart-rate by manipulating their emotions. (6) The reason that people use heart-rate as a predictor of emotion is because when we experience a variety of things we cause changes in our physical make-up. We tense our muscles, and increase our cardio-respiratory functioning when we are stressed, or relax our muscles and cardio-respiratory functioning when happy, or depressed. By recognizing the fact that there is a certain amount of conscious control in our experience of emotions, we can begin to understand more how they affect us in our everyday lives. When our emotional state is out of kilter with the external world, we can focus on why that might be and work to change it, or just enjoy it. If our emotions are in fact corresponding to the world around us, then it might be useful to realize that we can change them if we need to. For therapy and understanding aspects of people who continuously suffer from emotions that are in conflict with the way they should be, this understanding of conscious control might help in teaching them strategies to become more in sync with the world around them.
While emotions are not something that are always wonderful to experience, they can be quite useful in life. Their impact on memory makes them of special interest to those who study emotion and its effect on the nervous system. Memory is one of the areas where it is believed that we are changing the nervous system, specifically the connections in the brain on a daily basis. Studying how emotion is affected by and affects the nervous system can help us to understand better how memory works in our own minds. It has been shown that various parts of the brain play a role in emotion. The fact that it is many parts and not just one part is important because it supports and encourages the idea that emotion is a pattern of coordinated activity in the brain. It also allows for the idea that there is randomness in the system that can be occasionally controlled, and occasionally not controlled by aspects of the rest of the system.. Having a system which affects itself, and is affected by external forces is much like the nervous system as a whole, so by understanding this facet in greater detail, one might hope to understand the whole better as a result. References
1. Thinking and Feeling, Antonio R. Damasio
2. Larry Cahill
3. Glimpses of the Mind, Michael D. Lemonick
4. The Main Areas Involved with Emotions
5. Theories on the Role of Brain Structures in the Formation of Emotions: Comparison of the James-Lange and Cannon-Bard theories of emotion.
6. The Effects of Emotions on Short-Term Power Spectrum Analysis of Heart Rate Variability, Rollin McCraty MS, Mike Atkinson, William A. Tiller PhD, Glen Rein PhD and Alan D. Watkins MBBS
7. Limbic System: The Center of Emotions, Júlio Rocha do Amaral, MD & Jorge Martins de Oliveira, MD, PhD
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This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.