IQ & Psychometrics Glossary

Demystifying the terminology of intelligence research.

Psychometrics

Ceiling Effect

A measurement limitation that occurs when the highest possible score on a test is achieved by a significant portion of test-takers, making it impossible to distinguish between high-performing individuals.

Flynn Effect

The substantial and sustained increase in both fluid and crystallized intelligence test scores measured in many parts of the world over the 20th century.

G-factor

The general intelligence factor, also known as g, is a construct developed in psychometric investigations of cognitive abilities and human intelligence.

Reliability

The consistency of a measure. A test is considered reliable if it yields the same result on repeated trials.

Standard Deviation

A statistical measure that quantifying the amount of variation or dispersion in a set of data values. In IQ testing, it defines the spread of scores around the mean.

The Bell Curve (Normal Distribution)

A mathematical function that describes how IQ scores are distributed within a population, where most scores cluster around the center (100) and taper off at the extremes.

Validity

The extent to which a test measures what it claims to measure. In IQ testing, it refers to whether the test accurately assesses general intelligence (g).

Cognitive Science

Cognitive Reserve

The brain's ability to improvise and find alternate ways of getting a job done, often making it more resilient to the effects of aging or brain disease.

Crystallized Intelligence

The ability to use skills, knowledge, and experience. It does not rely on the ability to access information from long-term memory.

Dunning-Kruger Effect

A cognitive bias where people with low ability at a task overestimate their own competence, while those with high ability often underestimate theirs.

EQ (Emotional Intelligence)

The capability of individuals to recognize their own emotions and those of others, discern between different feelings and label them appropriately.

Executive Function

A set of cognitive processes that are necessary for the cognitive control of behavior, including working memory, flexible thinking, and self-control.

Fluid Intelligence

The capacity to think logically and solve problems in novel situations, independent of acquired knowledge.

Giftedness

An intellectual ability significantly higher than average, often characterized by high IQ scores, creative thinking, and rapid learning.

Metacognition

The awareness and understanding of one's own thought processes; literally, thinking about thinking.

Neuroplasticity

The brain's ability to reorganize itself by forming new neural connections throughout life, allowing the neurons in the brain to compensate for injury and adjust to new situations.

Pattern Recognition

The cognitive process of identifying regularities and trends in data, which is widely considered the core of human fluid intelligence.

Processing Speed

A cognitive ability that measures the time it takes a person to do a mental task. It is related to the speed in which a person can understand and react to the information they receive.

Savant Syndrome

A rare condition in which someone with significant mental disabilities demonstrates certain abilities far in excess of average.

Theory of Multiple Intelligences

A theory proposed by Howard Gardner suggesting that intelligence is not a single general ability, but rather a collection of eight distinct modalities.

Working Memory

The cognitive system responsible for temporarily holding and manipulating information for complex tasks such as reasoning, learning, and comprehension.

Genetics

Heritability

A statistical statistic used in genetics that estimates the degree of variation in a phenotypic trait in a population that is due to genetic variation between individuals.

Neurodiversity

Hyperlexia

A syndrome characterized by an intense fascination with letters or numbers and an advanced ability to read words at a very young age (often before age 5), usually accompanied by difficulties in understanding spoken language.

Societies

Mensa International

The largest and oldest high-IQ society in the world. It is a non-profit organization open to people who score at the 98th percentile or higher on a standardized, supervised IQ test.

IQ Tests

Raven's Progressive Matrices

A non-verbal group test typically used in educational settings. It is widely regarded as a pure measure of fluid intelligence.

Stanford-Binet Intelligence Scales

One of the most widely used and oldest intelligence tests in the world, originally developed by Alfred Binet and later refined at Stanford University.

WAIS (Wechsler Adult Intelligence Scale)

The most widely used IQ test for adults, designed to measure various cognitive abilities through verbal and performance-based tasks.

WISC (Wechsler Intelligence Scale for Children)

The most widely used intelligence test for children between the ages of 6 and 16. It is the pediatric version of the WAIS.

Creativity Research

Threshold Theory

A hypothesis concerning the relationship between intelligence and creativity, suggesting that a certain level of intelligence is necessary for high creativity, but beyond that level, the relationship weakens.

Educational Psychology

Twice-Exceptional (2e)

A term used to describe gifted children who have the potential for high achievement and give evidence of one or more disabilities as defined by federal or state eligibility criteria.