• Personality is organized and consistent.
• Personality is generally stable, but the environment can influence it. A shy personality in social situations might take charge and be more outspoken in an emergency.
• Personality causes behaviours to happen. You react to your environment based on your personality.

• Experimental methods are used by researchers to control and manipulate the variables of interests and then to measure the results. The ideas are internal, abstract, and difficult to measure.
• Case studies and self-report methods. Case studies rely on the observer's interpretations, and self-report methods depend on the memory of the individual of interest. These methods are highly subjective.
• Clinical research relies on information collected from clinical patients throughout treatment. This research is highly subjective.

• Biological Theories suggest genetics are responsible for personality traits.
• Behavioural Theories suggest that personality is the result of interaction between the individual and the environment.
• Psychodynamic Theories of personality emphasize the influence of the unconscious mind and childhood experiences on personality.
• Humanist Theories emphasize the importance of free will and individual experience in the development of personality.
• Trait Theories think personality is made up of several broad traits.

A trait is a stable characteristic or "blueprint" that causes specific behavioural patterns.

• The three dimensions of personality: extroversion, neuroticism, and psychoticism.
• Later researchers suggested five dimensions of personality (known as the Big 5 theory): openness, conscientiousness, extroversion, agreeableness, and neuroticism.

• Sigmund Freud: He was the founder of psychoanalytic theory. His theories emphasised the unconscious mind, childhood experience, dreams, and symbolism.
• Erik Erikson: He was an ego psychologist. His theory of psychosocial stages describes the development of personality throughout the lifespan.
• B.F. Skinner: He was a behaviourist and known for his research on operant conditioning and schedules of reinforcement.
• Sandra Bem: She developed a gender schema theory to explain how society and culture transmit ideas about sex and gender.
• Abraham Maslow: He was a humanist psychologist and developed the hierarchy of needs.
• Carl Rogers: He was a humanist psychologist and believed people have a drive to fulfil the individual potential that motivates behaviour.