IQ is one of the most-discussed and least-understood measurements in psychology. Most online writing falls into one of two camps: the score is destiny, or the score is junk. Both are wrong, in opposite directions.
The articles below are an attempt at the more honest middle. They cover what an IQ score is and isn’t, what each cognitive domain actually measures, and how the underlying research holds up under scrutiny. Each piece is research-backed and source-cited, written for a curious adult with no prior background in psychometrics.
The guide is organized into three themes. Start wherever your question lives.
Understanding the score
Before any individual domain matters, the score itself needs unpacking. What does the number mean? What does it predict? Why does the population average keep rising? These three articles cover the foundations.
What is a good IQ score?
"Good" depends on the goal. Research-backed thresholds for daily life, college, careers, and Mensa — plus the standard-error reality check most articles skip and honest score-by-score answers (is 110 good? 120? 130?).
Read article → FoundationsWhat your IQ score actually means
The 100-point scale, what IQ tests measure, what they predict, and what they don’t. Covers the Flynn Effect, online-vs-clinical assessments, and how to take a test for the most honest read.
Read article → ReferenceIQ classification ranges
Below average to gifted: what each classification band means, what percentile it represents, and why the boundaries between bands are interpretive rather than biological.
Read article → LifespanAverage IQ by age
Why fluid intelligence peaks in your 20s while crystallized intelligence keeps growing into your 60s. How age-norming works and why your raw score isn’t the same as your IQ.
Read article → ChildrenAverage IQ for a 12-year-old
It’s 100, by design. What a child’s score really means: percentile bands, gifted thresholds, which test it came from, the “mental age” idea, and why free online tests mis-score kids.
Read article → AdultsAverage IQ for an adult
It’s 100, by definition — but “the average adult” is a moving target. Why a 25-year-old’s 100 isn’t a 55-year-old’s, the Flynn-effect catch, and why online tests inflate adult scores.
Read article → TeenagersAverage IQ for a teenager
It’s 100 at 13, 14, 16 — every age. Why puberty isn’t a cognitive milestone, why a bright teen’s grades can still slip, and why the testing instrument itself changes at 16.
Read article →The six cognitive domains
An IQ score is a composite. Beneath the single number sit several distinct cognitive abilities, each measured by its own item types and each correlated with different real-world outcomes. These six articles cover what each domain is, what it predicts, and how it’s tested. Each links to a free 10-question mini-test for that domain.
Pattern recognition
The cognitive ability most tightly correlated with general intelligence (r ≈ 0.7). Matrix completion, sequence rules, and abstract reasoning under the Raven’s framework.
Read article → Domain · SpatialSpatial reasoning
Mental rotation, paper folding, and the cognitive ability with the strongest known link to long-term STEM achievement.
Read article → Domain · LogicLogical reasoning
Modus ponens, modus tollens, and why even educated adults fail basic logic tasks. The deductive ability behind law, philosophy, and software engineering.
Read article → Domain · NumericalNumerical reasoning
Sequences, ratios, hidden rules. The cognitive ability that predicts performance in finance, engineering, and quantitative research.
Read article → Domain · VerbalVerbal reasoning
Vocabulary, analogies, and the most trainable cognitive domain. Why verbal scores rise with education while fluid scores don’t.
Read article → Domain · MemoryWorking memory
The mental scratchpad behind every complex thought. Digit span, position memory, and why working memory is one of the strongest predictors of academic achievement.
Read article →IQ in context
A test score is only useful if you know what to do with it. These pieces cover the soft edges: how IQ compares to emotional intelligence, whether you can train it upward, and what the actual questions look like before you sit down.
IQ vs EQ
Are emotional intelligence and cognitive intelligence really independent? What the research says about how each predicts career, relationships, and life satisfaction.
Read article → ImprovementCan you improve your IQ?
The honest answer on brain training, dual n-back, and what actually moves the needle on cognitive performance versus what just inflates your test score.
Read article → PracticeIQ test sample questions
One worked example per domain with full solutions. Pattern, numerical, logical, verbal, spatial, and working-memory items, each with the reasoning explained step by step.
See examples →