PSYCHOLOGICAL ASSESSMENT NOTES

Francis Galton

Founder of the quantitative study of individual differences, pioneer of differential psychology, and father of psychology.

Nature vs Nurture

Term coined by Francis Galton relating to the debate on whether genetics (nature) or environment (nurture) shapes individual differences.

Eugenics

Scientifically disproved theory advocating the improvement of humans through selective breeding.

Charles Spearman

Pioneer of classical test theory (CTT) and developer of Spearman’s Rank Correlation Coefficient.

Classical Test Theory (CTT)

Framework for evaluating the reliability of psychological tests introduced by Charles Spearman.

True Score

Value representing an individual's score on a test if there were no measurement errors.

Error Score

Difference between an observed measurement and the true expected value.

Random Errors

Unpredictable errors due to various factors, causing variability in measurements.

Systematic Error

Consistent biases that skew results away from the true score due to inaccuracy in measurement.

Type I Error (False Positive)

Rejecting the true null hypothesis; incorrectly finding an effect or difference that doesn't exist.

Type II Error (False Negative)

Failing to reject a false null hypothesis; not detecting an effect when it actually exists.

Spearman’s Rank Correlation Coefficient

A statistical measure developed by Charles Spearman to assess the strength and direction of the association between two variables.

Factor Analysis

A statistical technique used to identify underlying factors that explain correlations among observed variables.

General Intelligence Factor (g)

Spearman's theory suggesting that individuals possess a general mental ability that influences performance across various intellectual domains.

Specific Abilities (s)

Unique abilities that individuals have to perform certain tasks, which can be learned but vary from person to person.

Hypothesis Testing

A method to determine whether there is enough statistical evidence in favor of a certain belief or hypothesis.

Blunders

Clear mistakes that cause errors in an experiment, like dropping a beaker before measuring mass.

Observational Error

Errors that occur when measurements are influenced by the observer's perspective or technique.

Environmental Error

Errors caused by external conditions affecting the measurement process.

Instrumental Error

Errors caused by inaccuracies in the measuring instruments used.

Example of a Specific Ability (s)

Mechanical, spatial, logical, and arithmetical abilities.