Trait/Biological Theories

Evolutionary vs. Biological

Evolutionary focus = similarities in personalities

Biological focus = differences in personalities through heritability

Heritability

How much of the variation among a population's traits can be attributed to genetics

Cannot explain how a single person’s traits are genetic vs. learned; can only be used for population

Trait vs. Biological Theories

Trait = identity unique traits for each person (describe personality differences)

Biological = quantify a given set of traits in each person (explain personality differences)

Gordon Allport

First trait theorist

Raymond Cattel

Developed "factor analysis" - a statistical analysis technique that identifies traits based on behaviors that tend to coincide

Hans and Sybil Eysenck

Identified 3 dimensions of personality (PEN: psychoticism, extraversion, neuroticism) and claimed they were genetically determined

The Big Five

Developed by Paul Costa & Robert McCrae

• Conscientiousness (careful, disciplined, organized)

• Agreeableness (gentle, trusting)

• Neuroticism (anxious, vulnerable)

• Openness (imaginative, spontaneous)

• Extraversion (sociable, outgoing)

Mostly stable over time and ~50% heritable

Personality inventories

Usually true/false or multiple choice questions that reveal the test-taker's feelings, attitudes, and behaviors; used to assess certain personality traits (big five)

Minnesota Multiphasic Personality Inventory (MMPI-2)

Assesses "abnormal" personality traits using empirically derived items

Most commonly used personality inventory

Strengths of trait/bio theories

Explains why personality traits run in families; quick and easy to score

Limitations of trait/bio theories

Biases; personality changes situationally; deterministic (personality can develop)