Anna Freud defined defense mechanisms as unconscious resources used by the ego to ultimately decrease internal stress.

Sigmund Freud’s theory explains that the adult personality is made up of the following:

• The ID which operates on the pleasure principle, generally within the unconscious.
• The Ego which operates on the reality principle within the conscious  realm.
• The Super Ego which operates on the morality principle at all levels of consciousness.

The interplay of these personality structures generates anxiety that is reduced by our defense mechanisms, acting to obscure the true, anxiety-laden reason’s for our behavior. 

Frued’s theories were dynamic in expanding our understanding of the human psyche, but aren’t near as valued in the scientific study of the human personality today however I still value them as good reference point for this lesson.

Defense Mechanisms are broken into to three categories, primitive, less primitive and mature defense mechanisms.

Primitive

• Denial: the refusal to accept reality or fact, acting as if a painful event, thought or feeling did not exist. It is considered one of the most primitive of the defense mechanisms because it is characteristic of early childhood development. Many people use denial in their everyday lives to avoid dealing with painful feelings or areas of their life they don’t wish to admit. For instance, a person who is a functioning alcoholic will often simply deny they have a drinking problem, pointing to how well they function in their job and relationships.
• Regression: The reversion to an earlier stage of development in the face of unacceptable thoughts or impulses. For an example an adolescent who is overwhelmed with fear, anger and growing sexual impulses might become clingy and start exhibiting earlier childhood behaviors he has long since overcome, such as bedwetting. An adult may regress when under a great deal of stress, refusing to leave their bed and engage in normal, everyday activities.
• Acting Out: Performing an extreme behavior in order to express thoughts or feelings the person feels incapable of otherwise expressing. Instead of saying, “I’m angry with you,” a person who acts out may instead throw a book at the person, or punch a hole through a wall. When a person acts out, it can act as a pressure release, and often helps the individual feel calmer and peaceful once again. For instance, a child’s temper tantrum is a form of acting out when he or she doesn’t get his or her way with a parent. Self-injury may also be a form of acting-out, expressing in physical pain what one cannot stand to feel emotionally
• Dissociation: When a person loses track of time and/or person, and instead finds another representation of their self in order to continue in the moment. A person who dissociates often loses track of time or themselves and their usual thought processes and memories. People who have a history of any kind of childhood abuse often suffer from some form of dissociation. In extreme cases, dissociation can lead to a person believing they have multiple selves or “multiple personality disorder”. People who use dissociation often have a disconnected view of themselves in their world. Time and their own self-image may not flow continuously, as it does for most people. In this manner, a person who dissociates can “disconnect” from the real world for a time, and live in a different world that is not cluttered with thoughts, feelings or memories that are unbearable.
• Compartmentalization: When parts of oneself are separated from awareness of other parts and behaving as if one had separate sets of values. An example might be an honest person who cheats on their income tax return and keeps their two value systems distinct and un-integrated while remaining unconscious of the cognitive dissonance. Compartmentalization is sometimes referred to as a lesser form of dissociation.
• Projection: The misattribution of a person’s undesired thoughts, feelings or impulses onto another person who does not have those thoughts, feelings or impulses. Projection is used especially when the thoughts are considered unacceptable for the person to express, or they feel completely ill at ease with having them. For example, a spouse may be angry at their significant other for not listening, when in fact it is the angry spouse who does not listen. Projection is often the result of a lack of insight and acknowledgement of one’s own motivations and feelings.
• Reaction Formation: The converting of unwanted or dangerous thoughts, feelings or impulses into their opposites. For instance, a woman who is very angry with her boss and would like to quit her job may instead be overly kind and generous toward her boss and express a desire to keep working there forever. She is incapable of expressing the negative emotions of anger and unhappiness with her job, and instead becomes overly kind to publicly demonstrate her lack of anger and unhappiness.

Less Primitive
Many adults find themselves using, or having used, less primitive defense mechanisms and find they work ok, however, they are not ideal ways of dealing with feelings, stress or anxiety.

• Regression: The unconscious blocking of unacceptable thoughts, feelings and impulses. The key to repression is that it happens unconsciously, so people often have very little awareness of it. “Repressed memories” are memories that have been unconsciously blocked from access or view. But because memory is very malleable and ever-changing, it is not like playing back a DVD of your life. The DVD has been filtered and even altered by your life experiences, even by what you’ve read or viewed.
• Displacement: The redirecting of thoughts feelings and impulses directed at one person or object, but taken out upon another person or object. People often use displacement when they cannot express their feelings in a safe manner to the person they are directed at. The classic example is the man who gets angry at his boss, but can’t express his anger to his boss for fear of being fired. He instead comes home and kicks the dog or starts an argument with his wife. The man is redirecting his anger from his boss to his dog or wife. Naturally, this is a pretty ineffective defense mechanism, because while the anger finds a route for expression, it’s misapplication to other harmless people or objects will cause additional problems for most people.
• Intellectualization: The overemphasis on thinking when confronted with an unacceptable impulse, situation or behavior without employing any emotions whatsoever to help mediate and place the thoughts into an emotional, human context. Rather than deal with the painful associated emotions, a person might employ intellectualization to distance themselves from the impulse, event or behavior. For instance, a person who has just been given a terminal medical diagnosis, instead of expressing their sadness and grief, focuses instead on the details of all possible fruitless medical procedures.
• Rationalization: Putting something into a different light or offering a different explanation for one’s perceptions or behaviors in the face of a changing reality. For instance, a woman who starts dating a man she really, really likes and thinks the world of is suddenly dumped by the man for no reason. She reframes the situation in her mind with, “I suspected he was a loser all along.”
• Undoing: The attempt to “take back” a behavior or thought that is unacceptable or hurtful. For example, after realizing you just insulted someone intentionally or unintentionally, you might spend then next hour trying to apologize or “fix it” hence, “undoing” the previous action, the person is attempting to counteract the damage done by the original comment, hoping the two will balance one another out.

Mature
Often the most constructive and helpful to adults, mature defense mechanisms may require effort and practice to put to daily use. 

• Sublimation: The channeling of unacceptable impulses, thoughts and emotions into more acceptable ones.. For example, when a person has sexual impulses they would like not to act upon, they may instead focus on rigorous exercise, redirecting their focus from unacceptable or harmful impulses into productive use can help channel energy that otherwise would be lost or used in a manner that might cause the person more anxiety. Sublimation can also be done with humor or fantasy. Humor, when used as a defense mechanism, is the channeling of unacceptable impulses or thoughts into a light-hearted story or joke. Humor reduces the intensity of a situation, and places a cushion of laughter between the person and the impulses. Fantasy, when used as a defense mechanism, is the channeling of unacceptable or unattainable desires into imagination. For example, imagining one’s ultimate career goals can be helpful when one experiences temporary setbacks in academic achievement. Both can help a person look at a situation in a different way, or focus on aspects of the situation not previously explored.
• Compensation: A process of “psychologically counterbalancing” perceived weaknesses by emphasizing strength in other arenas. By emphasizing and focusing on one’s strengths, a person is recognizing they cannot be strong at all things and in all areas in their lives. For instance, when a person says, “I may not know how to cook, but I can sure do the dishes!,” they’re trying to compensate for their lack of cooking skills by emphasizing their cleaning skills instead. When done appropriately and not in an attempt to over-compensate, compensation is defense mechanism that helps reinforce a person’s self-esteem and self-image.
• Assertive: The emphasis of a person’s needs or thoughts in a manner that is respectful, direct and firm. Communication styles exist on a continuum, ranging from passive to aggressive, with assertiveness falling in the middle. People who are passive and communicate in a passive manner tend to be good listeners, but rarely speak up for themselves or their own needs in a relationship. People who are aggressive and communicate in an aggressive manner tend to be good leaders, but often at the expense of being able to listen empathetically to others and their ideas and needs. People who are assertive strike a balance where they speak up for themselves, express their opinions or needs in a respectful yet firm manner, and listen when they are being spoken to. Becoming more assertive is one of the most desired communication skills and helpful defense mechanisms most people want to learn, and would benefit in doing so.

Keep in mind, defense mechanisms are most often learned behaviors which means, if you recognize that have poor or unhealthy defense mechanisms you can learn new, healthier ones.