Personality is a persons characteristics behavior pattern. Many people think of personality as being made up observable traits such as shyness, friendliness, and initiative. However, such traits are only the outward expression of various inner conditions and processes such as intelligence, attitudes, interests, and motives. Many psychologists include these inner elements in their definitions of personality.
Normal persons develop relatively consistent personalities that are distinguished by certain dominant traits. Persons belonging to the same cultural group”such as family or nation”have many traits in common. But each person exhibits different traits under different circumstances, and each has unique traits as well as those he or she shares with others. It is also known that personalities develop throughout life, and may even undergo fundamental changes as a result of psychotherapy or other treatment (Moskowitz, 2005). For these reasons, psychologists do not believe that personalities can be rigidly classified according to type.
Personality is produced by the interaction of heredity and environment. Inborn qualities affect the individuals response to the outside world, and the environment influences the way in which inborn capacities develop. However, the precise reasons why one person develops certain personality traits, while another develops other traits, are not known.
Studies of personality origins are limited by the difficulty of making controlled experiments on human behavior. Except for identical twins, no two persons have exactly the same biological inheritance, and even identical twins do not share exactly the same biological inheritance, and even identical twins do not share exactly the same environment. Parents and others respond to each twin differently, providing each with a unique emotional setting.
Inherited traits such as structure, skin color, and type of hair”play a part in personality only if given a meaning by the environment. For example, an extremely tall boy may develop either shyness or self-confidence, according to whether he is teased because of his height or praised for using it to advantage in playing basketball.
The structure and function of the nervous and glandular systems are inherited qualities having a more direct effect upon personality. Intelligence, talents, and skills are largely dependent upon these systems. However, the effects of even these qualities can be modified by the environment (Dana, 1999).
External Influences include both physical environment (climate, geography) and social environment (other individuals, and human institutions). Social influences are considered to be a greater importance in personality formation. Most psychologists believe that basic personality traits are acquired in early childhood, and that the family is therefore of primary importance in forming an individuals personality.
Wider cultural groups such as tribes and nations set up rules, values, and goals, and thus influence personality formation. Diversity within large groups is produced by subcultures such as social and economic classes and religious groups.
Psychologists have approached these tasks using a wide variety of research methods (Craik, 2005). Knowledge about peoples personalities can be obtained from their everyday conduct, as is the case in field studies. People also reveal themselves through the products of their imaginations, and this technique is used when personality tests known as projective tests are given to people. A straightforward approach to gathering personality data is to ask people to fill out self-report inventories about their characteristics.
With this method, two risks are apparent: People may not be fully aware of what they are like; and if they are, they may wish to cover up some of the flaws they perceive. We gain information of a different sort about personality when we ask others for their impressions of specific people.
This technique is known as the use of observer reports in research. Life histories, such as those biographies and autobiographies, and archival material, such as Van Goghs letters, provide a rich source of data on particular individuals for the study of personality. Clinical case histories, on which many of the major theories are based, fall into this category. The most carefully controlled information is maximized in laboratory studies; it is sometimes at the expense of naturalistic experiences.
No single source of information about personality is the ideal, correct source. All these methods are important for obtaining information about personality. Published research on personality, however, relies heavily on self-report inventories and laboratory studies with limited samples of people. Between 1990 and 2000, 85% of the research published in major journals used these two methods, and approximately two thirds of the research used undergraduate samples (Craik, 2005). However, there has been a trend in recent years toward greater use of biographical material, sometimes referred to as psychobiography, in the study of personality (Alexander, 2000).
Most people have implicit views of what personality is, just as they have implicit definitions of intelligence. Many different theories of personality exist. Different theories of personality have been based on different assumptions about human nature; on studies with diverse populations”clients seeking treatment, healthy, and happy adults, rats and pigeons; and on different focuses of analysis, such as emotions, behaviors, and cognitions.
Assessment of personality characteristics therefore depends heavily upon which type of personality theory is selected as the focus of study. Psychoanalytic theorists, for example, who subscribe to notions of the power they believe that major elements of personality are hidden even from the individual under study, only indirect methods of assessment are appropriate.
Behaviorists, on the other hand, are likely to approach personality directly by observing characteristics behaviors. Psychoanalytic theorists are more likely to look for traits; behaviorists are more likely to look for situational measures for personality. The assessment of personality is, therefore, a complicated business. Indeed, the enterprise of assessing personality is big business. There are now hundreds of tests designed to measure aspects of human personality (Piotrowski, 2004).
The most frequent used instruments for assessing personality are self-report inventories, which require individuals to answer a series of questions about themselves. One assumption underlying self-report inventories is that people know themselves better than anyone else knows them, and that they are therefore in the best position to provide personality information. Self-report inventories often contain a very large number of items that can be grouped into various categories of personal functioning (Janis, 1999).
The most widely used self-report inventory is the Minnesota Multiphasic Personality Inventory, or MMPI, which we briefly described earlier. The MMPI consists of more than 500 statements the individuals must respond to as being either true or false with respect to themselves, or indicate that they cannot say. The items cover a very large territory, ranging from family and marital issues to psychosomatic symptoms and political attitudes. Three sample items are:
At times I fell like swearing.
I like to flirt.
I believe I am being plotted against.
The MMPI yields scores on the 10 subscales and 3 response-tendency subscales. The MMPI is described as an empirical scale, which means that the items actually differentiate among groups of people. The MMPI differentiates between those who have been diagnosed as abnormal and those who have not. The procedure for establishing an empirical scale is fairly straightforward.
A group of clinical patients is selected to take the test. Their pattern of answers to the questions is compared to that of a group of normal individuals who also take the test. Items that differentiate between the two groups then form the basis for that subscale. With the MMPI, for example, paranoid patients are much more likely than normal people to answer true to the item I believe I am being plotted against. There is often some logic to the grouping of items, as in the preceding example; however, as long as they differentiate between the grouped empirically, items can be included on the subscale whether or not demonstrate any theoretical relevance (MacDonald, 2004).
The MMPI has proved to be an enormously popular test that has gone beyond its original purpose of differentiating between individuals. Today it is frequently used as a test of personality functioning for normal populations. The subscales consist of items grouped under misleading or even obsolete labels, however. Because of the purposes of the test have shifted, and because technical problems with the test and its standardization have arisen, the MMPI has undergone revision.
Items have been updated and reworded to eliminate sexist language. The original item pool has been supplemented with about 150 new items, and the entire test is being standardized in two forms, one for adolescents and one for adults (Anastasi, 2000). New items on the adult form address areas of psychopathology that were not covered in the original, and the adolescent form covers specific problems of adolescence.
A host of other self-report inventories assess characteristics that are related to personality. These include personality inventories for use with normal individuals, such as the California Psychological Inventory; sex-role inventories, such as the Bem Sex-Role Inventory; values scales, such as the Allport-Vernon-Lindzey Study of Values; and even scales designed to assess the need for thrill seeking, such as Zuckermans Sensation Seeking Scale.
All self-report inventories are similar in that individuals fill out the scales about themselves. They also share a common problem in that many of the characteristics can be faked (Korchin, 2001). It is usually obvious which answer is most socially desirable, so that an individual who is motivated to do so can choose only the desirable answers, in order to look good.
In some cases an individual might even want to pick the answers likely to make him or her look bad, as in the case of a person charged with a crime who wanted to be judged insane. Some self-report inventories, most notably the MMPI, contain a lie scale, several items that almost everyone who is telling the truth would answer as false. (Potential lie-scale items might be I never tell a lie or I have never been angry with a close relative.) A person who answers a large proportion of these items as true is assumed to be lying on the other parts of the test as well. The MMPI correction score is composed of a set of items that indicate attempts by the test taker to fake a good score (Morgan, 1999).
Self-report inventories are easily administered and provide a quick assessment of some aspects of personality. Their very ease of use has led to a problem of overuse. Some employers, for example, require personality tests such as the MMPI before an employee can be hired. The test was never designed as a screening device for employment and should not be used for such purposes. The availability of computer-based scoring and interpretation of the MMPI increases the risks for such abuse, because interpretation is complex and should be done only by trained clinicians.