Key Concepts in Psychology Statistics

Percentage of people experience déjà vu

Approximately 66%

Heritability estimate range for most personality traits in the Five Factor Model of Personality

0.4 - 0.5

Heritability estimate for intelligence in twin studies

Approximately 0.4 - 0.55

Heritability estimate for religiosity in twin studies

0.3 - 0.45, with increasing heritability with age

Heritability estimate for conservatism in twin studies

0.5 - 0.65, with increasing heritability with age

Average IQ score and standard deviation in a randomly selected population

Mean = 100, Standard Deviation = 15

Typical capacity of short-term memory in terms of items

Around 7 items on average

Percentage of cases that fall within 1 standard deviation (SD) of the mean in a normal distribution

68%

Percentage of cases that fall within 2 standard deviations (SD) of the mean in a normal distribution

95%

Percentage of people administered the highest shock (450V) in the Milgram experiment

Approximately 65%

Percentage of cases that falls within 3 standard deviations (SD) of the mean in a normal distribution

99.7%

Heritability estimate for extraversion in twin studies

Approximately 0.5

Percentage of psychology participants from WEIRD (Western, Educated, Industrialized, Rich)

80%

Percentage of people estimated to have mental health disorders according to DSM

20% in any given year

Number of neurotransmitters identified in the brain

Over 40 major neurotransmitters

Common p-value used to define meaningful results in statistical significance

A p-value of 0.05

Typical attrition rate in psychological research, particularly for human studies

20-50%

Percentage of people who use social media and experience related depressive symptoms

65%

Heritability of anxiety disorders in twin studies

Approximately 0.4 - 0.5

Capacity of long-term memory in terms of duration and capacity

Not specified in the notes.

Unlimited duration and capacity

A concept referring to the limitless nature of certain psychological processes.

Percentage of people diagnosed with a psychological disorder

Approximately 50% of people will be diagnosed with a psychological disorder at some point.

Percentage of people valuing self-expression in individualist societies

80% of people in individualist societies value self-expression over group needs.

Crystallized IQ

Crystallized IQ increases with age.

Fluid IQ

Fluid IQ decreases with age.

IQ correlation with brain structures

IQ is correlated with white matter integrity, brain size, neuron number, and cortical thickness, but cortical thickness declines with age.

Age's effect on personality traits

As you age, you become more comfortable with your personality and have less desire to change, though small changes are possible with effort.

Heritability of religiosity and conservatism with age

Heritability of religiosity and conservatism increases with age, ranging from 0.3 - 0.45 for religiosity and 0.5 - 0.65 for conservatism.

Personality traits increasing with age

Agreeableness and Conscientiousness tend to increase, while Extraversion and Openness tend to decrease.

Personality traits correlated with job performance

Certain personality traits are strongly correlated with job performance.

High Conscientiousness, low Neuroticism, and high Agreeableness

Predict strong job performance.

Extraversion Heritability (Adult Samples)

0

Agreeableness Heritability (Adult Samples)

0

Conscientiousness Heritability (Adult Samples)

0

Neuroticism Heritability (Adult Samples)

0

Openness Heritability (Adult Samples)

0

Psychiatric Illnesses (Schizophrenia)

0

Psychiatric Illnesses (Major Depression)

0

Psychiatric Illnesses (Panic Disorder)

0.30 - 0.40

Psychiatric Illnesses (Phobias)

0.20 - 0.40

Psychiatric Illnesses (Alcoholism)

0.50 - 0.60

Social Attitudes (Conservatism under age 20)

0

Social Attitudes (Conservatism over age 20)

0.45 - 0.65

Social Attitudes (Right-wing Authoritarianism - Adults)

0.50 - 0.64

Social Attitudes (Religiosity for 16-year-olds)

0.11 - 0.22

Social Attitudes (Religiosity for Adults)

0.30 - 0.45

Intelligence Heritability (Age 5)

0.22

Intelligence Heritability (Age 7)

0.44

Intelligence Heritability (Age 10)

0.54

Intelligence Heritability (Age 12)

0.85

Intelligence Heritability (Age 16)

0.62

Intelligence Heritability (Age 18)

0.82

Intelligence Heritability (Age 26)

0.88

Intelligence Heritability (Age 50)

0.85

Intelligence Heritability (Old Age >75)

0.54 - 0.62