The Science of Personality Development

Explore theoretical explanations for personality development, how psychologists study the topic, and why personality disorders occur.

Our personalities are evaluated by employers. Quizzed by the internet. Divined by horoscopes and studied by scientists. Personality formation serves as a cornerstone of understanding who and what we are. As a result, it is a key subject of psychological research.

Dr. John Kim, assistant professor of psychology and applied therapies at Lesley University, defines personality as “the characteristic ways of thinking, feeling, and behaving that account for the ways in which people are relatively consistent across situations.” Studying personality, Kim explains, means asking the question “why are specific people generally the way they are?” The broad nature of this question has led to an array of approaches for understanding personality development.

Theoretical Explanations

How personalities form isn’t entirely known. However, many theories exist. Here are just a few.

Psychoanalytic Theory

Sigmund Freud, the founder of psychoanalysis, developed psychoanalytic theory, which assumes that personality reflects the workings of the unconscious mind, according to Psychology: A Concise Introduction. Freud believed personality was divided into three sections, each with its own distinct function:

  • Id

    Responsible for basic human instincts, natural urges, and natural temperaments. It is located completely in the unconscious mind.

  • Ego

    Also referred to as the “self,” it helps the Id obtain what it wants by applying judgment. It is in both the conscious and unconscious mind.

  • Superego

    Section responsible for morality and applying pride and guilt. It is in both the conscious and unconscious mind.

Humanistic Theory

Abraham Maslow conceived humanistic theory in the 1950s. He believed that psychoanalytic theory, with its emphasis on abnormal personality, was flawed. Instead, Maslow stressed the importance of understanding the conscious mind and personality in their normal states. Humanistic theory assumes that humans have free will and that people make choices based on an ultimate desire for self-excellence. Personalities are based on subjective experiences and individuals’ interaction with their environment.

The humanistic theory of personality eventually led to Maslow’s famous Hierarchy of Needs model, which suggests that as people’s basic needs are met, they are replaced with ones that are increasingly complex. Simply Psychology outlines the five levels of need. Highest to lowest, they are:

  • Needs of self-actualization
  • Needs of esteem
  • Needs of love/belonging
  • Safety needs
  • Physiological needs

Trait Theory

Largely defined by Gordon Willard Allport, trait theory claims that personality is composed of a collection of characteristics within an individual, called traits. These characteristics help express the uniqueness of each person and can be divided into three main types: 

  • Cardinal Traits

    Pervasive, dominant traits that influence nearly every aspect of behavior and personality. These are rare.

  • Central Traits

    Five to 10 characteristics that define the basic qualities of an individual. These might include intelligence, for example, or shyness.

  • Secondary Traits

    They are dependent on context. An example might include a preference for certain foods or colors.

Trait theory is the personality development model most directly based on research data, according to Personality Theories: Critical Perspectives.

Social Cognitive Theory

Developed by Albert Bandura, social cognitive theory stresses that personalities are formed based on social contexts. It assumes two key principles, according to Williams and Cervone:

  1. The inner psychology of individuals, their environment, and their behavior all influence each other.
  2. People are best understood in terms of three types of cognitive abilities: those that help them represent events symbolically in their minds, self-reflect, and self-develop. 

According to social cognitive theory, personality formation occurs when people observe the behaviors of others. This leads to adaptation and assimilation, particularly if those behaviors are rewarded. Social cognitive theory is often considered a bridge between personality theories that emphasize behavior and those that emphasize cognition.

Kim provides insight into the real-world applications of the four theories within the field of psychology:

  • Psychoanalytic theory encourages clinicians to take a “past-focused” and “under-the-surface” approach to treatment. Counselors may often look at early life events of their clients in order to provide better care.
  • Humanistic theory encourages counselors to approach client problems from a present-focused view.
  • Trait theory is useful in the scientific study of personality (as opposed to therapeutic services). It allows researchers to see the connection between characteristics, thoughts, feelings, and behaviors.
  • Social cognitive theory helps researchers inform their knowledge of social psychology. This allows them to study ways in which situations can cause people to display personality inconsistencies.

Assessing Personality

When assessing personality, clinicians often turn to two main types of evaluations: objective and projective tests.

Objective tests measure aspects of an individual’s personality in relation to academically recognized norms. The most common example is the Minnesota Multiphasic Personality Inventory, or MMPI-2. (The test was originally published in 1940 and then revised in 1989.) On the MMPI-2, individuals must answer 567 true/false questions in a 60- to 90-minute session. Questions on the MMPI-2 identify potential personality features such as anger or addiction. The test is comprehensive and designed to ward against false positives and lying. MMPI-2 evaluations are often used in settings such as mental health and medical fields. They are also common when evaluating candidates for “high-risk” occupations such as airline pilots and nuclear power plant workers, according to Occupational Medicine.

Projective tests are subjective evaluations that ask clients to respond to ambiguous stimuli, such as words or visual images. An individual’s reply is meant to help reveal his or her internal struggles and emotions. The Rorschach Inkblot Test is a classic example of a projective test. After looking at 10 inkblots of varying shapes and colors, clients are asked to describe what they see. Answers are interpreted based on factors like subject matter, the kind of shapes or colors emphasized, and the location of the seen image. While the Rorschach test is useful, Kim views it as one of many tools and notes that it is not adequate for understanding the nuances of personality on its own.

Personality Disorders

When personality becomes problematic for daily living, it is considered a disorder. The Mayo Clinic defines a personality disorder as characterized by rigid or unhealthy patterns of thinking, functioning, or behavior.

“It is very important,” Kim explains, “that we do not conflate personality disorders with what is simply personality. A personality disorder … is profoundly disruptive to an individual’s daily life. ‘Profoundly disruptive’ is not the same thing as simply being irritating.”

Personality disorders fall into three main clusters:

  • Cluster A

    Disorders defined by eccentric thinking or odd behavior. Examples include paranoid personality disorder, schizoid personality disorder, and schizotypal personality disorder.

  • Cluster B

    Disorders defined by behavior and thinking that are excessively emotional or unpredictable. Examples include narcissistic personality disorder, antisocial personality disorder, and borderline personality disorder.

  • Cluster C

    Disorders defined by thinking and behavior that is excessively anxious and fearful. Examples include avoidant personality disorder, depending personality disorder, and obsessive-compulsive personality disorder.

Although experts still don’t fully understand how personality disorders come about, there appear to be certain contributing factors. The American Psychological Association suggests the following influences:

  • Genetics
  • Childhood trauma
  • Verbal abuse
  • High sensitivity

Oppositely, personality disorders may be prevented by consistent, positive interaction with peers.

Additional sources: Bandura’s Social Learning Theory & Social Cognitive Learning Theory, Psychological Testing Associates, Britannica

Personality Assessment and Your Psychology Career

The human personality is a fascinating subject and just one of many exciting areas in the field of psychology. At Lesley University, the online Bachelor of Arts in Psychology degree offers a relevant course of study designed to help you grasp the complexities of the human brain. Our curriculum covers mental processes, cognition, abnormal behavior, and more, giving you the foundation you need to start careers in mental health or advance to graduate study. A required internship provides you with valuable real-world experience for your future career.