Humanistic theories, particularly those developed by Carl Rogers and Abraham Maslow, take a more optimistic view of personality development compared to psychoanalytic theories. Instead of focusing on unconscious conflicts and psychosexual stages, humanistic theories emphasize the inherent goodness of people, their potential for growth, and the importance of self-actualization. Carl Rogers introduced the concept of self-concept and the importance of unconditional positive regard from others, suggesting that a positive self-view and a supportive environment are crucial for an individual to reach their full potential. Abraham Maslow's hierarchy of needs places self-actualization at the pinnacle, proposing that individuals are motivated by a hierarchy of needs that culminates in the realization of their personal potential. This contrasts with Freud's view, which often depicted personality development as a struggle to resolve conflicts between base instincts and societal demands. Humanistic theories also emphasize the role of free will and personal choice in shaping one's personality, suggesting that individuals have more control over their development than psychoanalytic theories typically allow.

In psychoanalytic theories, defense mechanisms are psychological strategies brought into play by the unconscious mind to manipulate, deny, or distort reality in order to defend against feelings of anxiety and unacceptable impulses and to maintain one's self-schema. These mechanisms are considered crucial for understanding personality because they operate at an unconscious level to help the ego resolve conflicts between the id's basic urges, the superego's moral standards, and the limitations of the external world. Examples include repression, denial, projection, rationalization, displacement, and sublimation, among others. For instance, repression involves unconsciously blocking unacceptable thoughts from conscious awareness, while projection involves attributing one's own unacceptable desires to others. Freud believed that the use and reliance on different defense mechanisms shape an individual's personality and can lead to either healthy or maladaptive outcomes, depending on how these mechanisms are used and the balance they strike between the id, ego, and superego.

Social-cognitive theories, particularly those proposed by Albert Bandura, emphasize the concept of self-efficacy as central to understanding personality. Self-efficacy refers to an individual's belief in their capacity to execute behaviors necessary to produce specific performance attainments. Bandura argued that self-efficacy affects almost every aspect of human endeavor, by determining the goals individuals choose to pursue, the amount of effort they will expend towards achieving those goals, their persistence in the face of difficulties, and their resilience to setbacks. In the context of personality, high self-efficacy can lead to a more proactive, confident, and resilient personality, while low self-efficacy can result in avoidance behaviors, low self-esteem, and a sense of helplessness. This contrasts with psychoanalytic theories, which focus more on unconscious processes and past experiences. Social-cognitive theories provide a more dynamic and interactive model of personality, where cognitive factors like beliefs and attitudes (including self-efficacy) interact with behaviors and environmental contexts to shape personality.

Cognitive theories, especially George Kelly's personal construct theory, explain personality in terms of how individuals construct and interpret the world around them. Kelly proposed that individuals use a set of personal constructs — bipolar dimensions of judgment, such as fair-unfair, smart-dumb, or exciting-dull — to make sense of their experiences and to anticipate future events. These constructs are unique to the individual and are developed based on personal experience. They function as mental filters through which we perceive the world, influencing our reactions to people and situations. According to Kelly, differences in personality arise from the unique set of personal constructs each person develops, and the way these constructs are applied in interpreting experiences. This contrasts with psychoanalytic theories, which focus more on the influence of unconscious processes and childhood experiences. Cognitive theories view personality as more fluid and adaptable, shaped by ongoing cognitive processes and the ability to revise constructs based on new experiences.

Behavioral theories, notably those advanced by B.F. Skinner, posit that personality is shaped through a process of operant conditioning, where behaviors are influenced by the consequences that follow them. Reinforcement, whether positive (adding a desirable stimulus following a behavior) or negative (removing an undesirable stimulus following a behavior), increases the likelihood of a behavior being repeated. Conversely, punishment, whether positive (adding an undesirable stimulus following a behavior) or negative (removing a desirable stimulus following a behavior), decreases the likelihood of a behavior being repeated. Skinner argued that through this process of reinforcement and punishment, individuals learn patterns of behavior that become characteristic of their personality. Unlike psychoanalytic theories, which emphasize internal drives and unconscious conflicts, behavioral theories focus on the observable and measurable aspects of behavior and how they are shaped by the environment. This perspective suggests that personality is not a fixed entity but is continuously shaped and reshaped by ongoing interactions with the environment.