Personality is a broad term describing how people habitually relate to the world and their inner self. After the developmental period through childhood and adolescence, these patterns of relating remain reasonably stable through life. They are then referred to as traits and influence behaviour, thinking, motivation and emotion.
Since everyone is different in their own way, psychologists have debated how to characterise personality. The most popular approach has so far been to use five dimensions: openness to experience (curious or cautious), conscientiousness (organised or careless), extraversion (outgoing or solitary), agreeableness (friendly or detached) and neuroticism (nervous or secure).
A self-report questionnaire is often used to give a score to each dimension, which then describes someone’s personality. These descriptions have been used to understand normal and abnormal behaviour, and to predict work success, academic achievement and interpersonal relationships.
Both genetic and environmental factors determine someone’s personality. Genes account for between 30-50% of the determination and the rest is made up largely of environmental experiences unique to the individual.
History of personality
Understanding the neurological physiology of personality is sometimes seen as the holy grail of psychology, and was the topic of Sigmund Freud’s first paper, Project for a Scientific Psychology, in 1895.
Early developments in this field came from historical case descriptions.
The classical case is of Phineas Gage (1823-60), an American railroad worker who had a large iron rod driven completely through his head in an accident, which destroyed most of his left frontal lobe and resulted in a profound personality change.