In the field of psychology, there are several major personality theories that attempt to explain who people are and why they act as they do. Theories categorise people based on their characteristics or traits, then describe how these traits influence their behaviours in various situations. Personality theory focuses on how people differ from one another; theories select different behaviours or characteristics to determine their taxonomies or categories.
Trait theory focuses on identifying patterns of behaviour within an individual. These traits are considered to be stable or unchanging; people will act the same way over time and across different situations. Psychologists measure these traits by using a variety of measures, including self-report assessments such as the Minnesota Multiphasic Personality Inventory (MMPI) or social desirability scales. Traits can also be measured using observed behaviours. A major trait theory is the five-factor model of personality, which uses five traits to describe people: extroversion, neuroticism, openness, agreeableness and conscientiousness. Prominent psychologists such as Henry Murray have stressed the importance of considering the interaction between situation and individual as well as considering the motivation behind a person's behaviour.
Behavioural and Social Learning Theory
Behavioural theories state that our behaviours and responses in situations are learnt through association and consequences. Behaviours that are reinforced, or rewarded, will increase in frequency, while those that are punished or not reinforced will occur less frequently. Individual or personality differences will determine how people value different types of reinforcement. For example, someone who enjoys attention from others may be reinforced by speaking in public; another person may decrease their speaking in front of others after becoming anxious. Researchers like Albert Bandura claimed that not only is our behaviour influenced by the environment, but we also change the environment through our behaviour. Social-learning theory states that we learn behaviour through modelling or observing what others do. Then, we utilise self-regulation to modify our behaviour by observing and judging ourselves, which forms our self-concept.
Biological theories of personality focus on the role of genetics as well as biological correlation of behaviour such as physiological arousal and changes in the neurochemistry in our brains. Researchers in psychology frequently study twins to examine similarities and differences between monozygotic and dizygotic twins. An example of a biological approach to studying personality is examining the differences in brain chemistry between people categorised as extroverts and introverts.
Personality theories in the cognitive describe personality as the way we interpret and make sense of the world. We use schemata, or sets of beliefs about the world, to help us organise and process the information we get from our experiences. We also have self-schemata that determine how we perceive ourselves and the events that happen to us. For example, some people have an internal locus of control, where they feel they are responsible for events that occur and the experiences they have. Others have an external locus of control and perceive others or the environment as responsible for events. Similar to other theories, there is an emphasis on the interaction between personality and environment: Someone with an internal locus of control may perceive failing a test as a result of his own faults and experience decreased self-esteem, whereas someone with an external locus of control may perceive the same outcome as a result of outside factors such as the test being unfairly difficult.
Theories in evolutionary psychology attempt to explain behaviour by determining how the behaviour has been helpful to us as a species. Natural selection states that behaviours that are advantageous to a species' survival will be more likely to develop and continue as the species evolves. For example, individuals who were more cautious may have avoided dangerous situations and been more likely to survive; the personality trait of anxiety could have developed this way. Unfortunately, because of the retrospective nature of this theory, nothing can be scientifically examined or verified.
John Holland & Career Choice
John Holland developed a theory of career choice that relates closely to personality. Holland's theory describes six personality types that people fall into: realistic, investigative, artistic, social, enterprising and conventional. These personality types interact with different work environments, which Holland describes using the same taxonomy. His theory proposes that people who work in environments that are congruent with their personalities are more likely to be satisfied and successful in their careers.