Personality assessment Week 3

Today’s outline Personality as human nature Trends in personality research Classification Understanding Prediction Interactionist Biological models What makes a good personality test? One remaining but very fundamental issue

Human nature

People want to understand themselves and others Astrology Humors Phrenology Personality tests Sometimes driven by external events WWII Industrialization

Personality test explosion 2500 test publishers in the US US$400 million industry SAT, GMAT, GRE, WISC, etc. Check your Facebook Color preference and personality

Trends in personality reseach

Trends in personality research: Classification (A) Classifying “normals” vs. abnormals MMPI (next week) Rorsarch (next week) (B) Analyzing “normals” MBTI Misusing tests for (A) onto (B) This is a clear mismeasure Suddenly, you see lots of abnormal people around 47% of the normal Rorschach test-takers will be labeled as having "distorted thinking."

Trends in personality research: Understanding Cattell’s 16PF was originally intended to be a ‘periodic table of personality’ Available here: But it was criticized as having too many PF: Warmth, Reasoning, Emotional stability, Dominance, Liveliness, Rule-consciousness, Social boldness, Vigilance, Abstractness, Privateness, Apprehension, Openness to change, Self-reliance, Perfectionism, Tension Based on Lexical Hypothesis: If a personality is ‘real’, there must be a word for it ↔ if there is a word for a trait, it must be a real trait

Trends in personality research: Understanding Others found 5 basic personality traits (i.e., Big 5): OCEAN Recall the questionnaire you completed. That was the Big 5. Let’s compare the statistical structure of your Big 5 with MBTI If the MBTI were true, then responses to the Big 5 should be bimodal. Is that true?

But first, what does ‘bimodal’ mean? Many traits are approximately normally distributed.

But first, what does ‘bimodal’ mean?

Statistical structure of your Big 5 response Is the distribution bimodal?

Implications on MBTI The MBTI’s claim that people can be (neatly) classified into types is fundamentally wrong – the data just doesn’t fit the theory! Why is the MBTI so popular? Politically correct – there’s no need to change oneself or the workplace, because success/happiness depends on fit Projective tests (next week) are threatening (they claim to analyze your unconscious), but MBTI is comforting Barnum effect increases believability Barnum effect Irresponsible arm-chair philosophy?

Trends in personality research: Predicting Psychologists usually aren’t interested in describing personality, but predicting/explaining

Make a guess: Which personality trait(s) predict well-being? (O)penness to Experience (C)onscientiousness (E)xtraversion (A)greeableness (N)euroticism

Which items measure which OCEAN domain? Let’s have a look

What does your data say?

Mismeasures Personality correlates negatively with creativity Personality correlates positively with compliance So does personality predict performance? Both can cancel out Depends on what you mean by performance

Tautology in personality Tom doesn’t like to socialize Tom is an introvert How do you know Tom is an introvert? Because he doesn’t like to socialize

Trends in personality research: Interactionist B  P x E Behavior is a function of personality characteristics and environment

The personality construct controversy: Walter Mischel Personality is by definition something stable in that person But if people’s behaviors are influenced by situational factors… …doesn’t that mean that personality cannot exist.

Trends in personality research: Biological models Psychophysiological Testosterone markers and aggression Oxytocin and love, social trust, etc. Neuroscience But results are rarely straightforward (see Week 8 on neuroscience)

What makes a good personality test?

Some personality tests can be faked Social desirability of self-reports This makes projective tests (next week) attractive – if you are not aware of your unconscious desires, you can’t fake it.

Good personality tests are reliable over time, and valid Big 5 – 40 year olds, over 6 to 9 years, test-retest correlation.83 Strong predictive validity Neuroticism: mental/physical health

One last issue

A very fundamental issue Can we measure personality at all? Two camps Narrative (qualitative) psychology: life story method Quantitative psychology: questionnaire method We are always back to the same question we asked thousands of years ago: who are we?