Heredity, Environment, and Personality

Since the moment you were born, biology has influenced your behavior in ways that may have seemed insignificant then, but are more relevant now. For instance, active babies frequently look around the room and at the people in it, whereas a quieter baby tends to hold a steady gaze in one direction, focusing on a single activity. Granted, these babies may grow up to develop adult personalities that are quite different from their newborn personalities, but studies have shown that these characteristics are often a good indicator of who the child will grow to be. In addition to biological factors, both common and unique life experiences help shape your personality.

Biological Factors

Determining the amount of genetic influence that contributes to the makeup of personality has proved to be a difficult task. However, in studying both fraternal and identical twins, we're able to gain some insight into this mystery. After a series of tests, studies have shown that identical adult twins were more likely to answer questions in the same way than fraternal twins were. In subsequent studies, identical twins who were separated for long periods of time compared to those who weren't separated continued to exhibit the same level of personality traits.

Physiological Differences

Monoamine oxidase (MAO) is an enzyme that functions in the nervous system by breaking down the neurotransmitters said to be a key factor in emotional and motivated behavior. It's an important element to consider, because the levels of MAO in a person's body change due to age and sex hormones. Also, since MAO is an inherited, physiological trait, adventurous parents, for instance, pass that trait along to their offspring and are more likely to have children who are just as adventurous as they are than parents who are not adventurous at all.

Shared Versus Solitary Experiences

Your surroundings and the common belief systems that are established and shared within those surroundings are major contributing factors in the development of your personality. Culture, religion, education, custom, and family tradition all have something to say about how you should act. Even the most extroverted person would behave in a subdued manner at a funeral, while a normally shy person may try to be more outgoing when hosting a bridal shower. One instance of how adults conform to the general standards of society takes place in the business world. You wouldn't walk into a board meeting of executives wearing jeans and a T-shirt; rather, you'd wear a professional suit or jacket and skirt. Similarly, you're not going to walk into church wearing a bikini top, sarong, and flip-flops, and you probably won't attend a barbecue wearing a prom dress.

Biological and social differences aren't the only factors influencing your personality. Individual experiences make their marks in your life especially because of the personal nature in which they are dealt with. For example, if the last jar of honey in the house contains only one drop, Winnie the Pooh views it as a positive experience because there's still one drop left; Piglet is anxious because he's afraid the honey will attract bees; and Eeyore thinks they're all doomed because the food supply has dwindled down to only one drop of honey. How can three individuals be in the same situation yet view it differently?

Past experiences affect attitudes and sway reactions. Pooh realizes there is more honey in the forest, Piglet recalls how much it hurt the last time he was stung by a bee, and Eeyore thinks there won't be any more honey left in the forest because he is used to never getting what he wants. Surely it will be gone before they get to it! This scenario illustrates how a delicate blend of common and unique experiences, external influences, and inherited characteristics are the makings of a full-bodied personality, unique in its own right, despite the situation. Personality development operates on multiple levels and can be examined by breaking it down into four different perspectives: traits, psychodynamic, psychoanalytic, or humanistic (phenomenological).


The trait theory, introduced by Gordon Allport (1897–1967), is the belief that the individual qualities of a person are what determine her behavior. The theory also holds that these traits can be measured on dimensions, or scales, each one measuring a characteristic, or trait, of that person. Some examples include rating a person's scale of aggressiveness and emotionality. Is that person quick to get angry? Does she cry easily? How trusting is she? But with all the different types of personality traits available to describe, how do you arrive at determining what traits are most important?

Factor Analysis

Factor analysis is the statistical method used to help interpret the scores of multiple personality tests by computing the minimum number of characteristics needed to discover the truest assessment of that personality. For example, when measuring the trait dimension of cheerfulness, you would fall somewhere between serious and enthusiastic, the former having the lowest rating of 1 point and the latter having the highest rating of 10 points. Raymond Cattell (1905–1998), after extensive research, testing, and data collecting, concluded that sixteen factors make up the basic elements of personality. Following is a list of these factors:

  • Warm

  • Suspicious

  • Intelligent

  • Imaginative

  • Emotionally stable

  • Shrewd

  • Dominant

  • Guilt prone

  • Cheerful

  • Experimenting

  • Conscientious

  • Self-sufficient

  • Bold

  • Self-disciplined

  • Sensitive

  • Tense

  • A trait is considered to be a relatively stable characteristic of your personality. Though your personality certainly changes somewhat due to the environment you are in, traits, such as race or age, are supposedly those that are always underlying and never affected by changing situations.

    Each trait is rated on a scale of 1 to 10 points in which each level is assigned an adjective, as seen in the previous example with cheerfulness. Cattell also developed a questionnaire of over 100 yes-or-no questions to measure the level at which each person possesses the traits listed and to be able to create as accurate a personality profile as possible for each individual based on his answers to the questions.

    Problems with the Trait Theory

    Although the trait approach succeeds at determining the character of a person based on her tendency to lean one way or another regarding certain traits, it doesn't really paint a complete picture. Introversion-extroversion and stability-instability levels prove that behavior can sometimes depend on the situation at hand. Someone who is shy and quiet around acquaintances at the office may let loose and be outgoing on the weekends around her friends. Similarly, a twelve-year-old boy may be nervous and well behaved around his strict parents, but his aggressiveness increases when he's around his friends in the schoolyard. Psychologists have found that developing tests to measure personality is not an easy task, especially since individual experiences and interactions in social situations pave erratic paths that are difficult to follow.

    Differing Views of Personality

    The main target of trait theorists is the behavior of the individual, whereas social-learning theorists believe external elements, such as the environment, hold the key to understanding what causes particular types of behavior. They also believe that both individual and environmental aspects work together by ultimately contributing to each situation indirectly. Understanding how a person handles certain situations based on his personal traits is the first step toward pinpointing behavior patterns.

    Aiding and Abetting Behavior

    Rewards and punishments — reinforcements — influence your behavior in many ways and are encountered by direct, vicarious, and self-administered learning. Instances of direct reinforcements include concrete rewards of money, plaques, and trophies, as well as punishments that include being yelled at, denounced, or taking something important to the person away from her. Through vicarious learning, you think twice about doing something because you remember observing a similar situation with someone else, or you recall a story a friend or coworker told you that involved the same variables. Your behavior is then affected by your thoughts and conclusions about whether or not the observed behavior was favorable.

    If you've been feeling a little blue lately or even if you're just having a bad day, look at yourself in the mirror and (out loud) tell yourself how great you are. It may seem silly and will probably make you laugh (is that such a bad thing?), but it will also likely improve your mood somewhat.

    Finally, reinforcements that are self-administered may arguably be the most powerful contribution to your overall demeanor. Statements you administer to yourself like “I can do it,” “Hang in there,” “I look good,” “I look bad,” “I'm too tall,” or “This is my color” shape your personality in that they can either build or crush self-esteem and in return, project a positive or negative image of who you are to the world.

    Reacting to Situations

    Personality is determined by many factors and functions on many levels. Thus, social-learning theorists contend that your behavior and reactions to situations are the combination of the specifics of the situation at hand, how you see those situations, and what you learned from observing similar situations in the past. Distinctive personal differences come to the forefront of your thoughts when you're preparing to react to a given situation. The following list is a compilation of some of those differences that social-learning theorists think are important:

  • Proficiency — intellectual, physical, and social skills

  • Point of view — interpretation of situations and opinions

  • Estimation — determining whether results of behavior will be favorable or rejected

  • Level of importance — behavior in one situation may be more important than behavior in other situations (for example, performing acts to impress coworkers and performing acts to impress the boss)

  • Personal goals — the ability to set realistic goals and act accordingly in order to achieve them

  • The relationship between the previous behavioral differences and the situations you encounter on a daily basis follows a give-and-take model. What you contribute is what you get back. Acting disinterested toward people who approach you causes them to stop approaching you, leaving you in a self-created world of solitude. Being friendly and responsive to people will make them feel warm and encourages them to approach you.

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