Intelligence is the ability to learn, understand, reason, and apply knowledge to solve problems. It includes a range of cognitive abilities such as memory, reasoning, problem-solving, and adapting to new situations.

An IQ (Intelligence Quotient) test is a standardized assessment that measures cognitive abilities relative to others. Scores are based on comparisons to a normed sample, with 100 as the average score.

An IQ score indicates how your cognitive abilities compare to the general population. A score of 100 is average, while higher or lower scores reflect above-average or below-average cognitive functioning, respectively.

IQ tests typically assess:

• Verbal reasoning - Understanding and analyzing language-based information.

• Spatial ability – Visualizing and manipulating objects in space.

• Fluid reasoning – Solving novel problems using logic and reasoning.

• Working memory – Holding and processing information in short-term memory.

• Processing speed – Quickly and accurately handling simple information.

IQ testing began in 1905 with the Binet-Simon Scale, developed to assess children's intelligence. Since then, tests like the Stanford-Binet and Wechsler scales have evolved to provide more comprehensive assessments.

Alfred Binet and Théodore Simon developed the first practical IQ test in 1905 to identify children who needed special educational assistance.

Modern IQ tests use a deviation IQ system, where an individual's score is based on how their performance compares to that of a large, representative sample. The average IQ is 100 with a standard deviation of 15, meaning most people score between 85 and 115. IQ scores are statistically derived by converting raw test performance into a standardized scale, allowing for meaningful comparisons across populations.

The CHC Theory is a widely accepted model of intelligence that organizes cognitive abilities into broad and narrow categories, including fluid reasoning, crystallized intelligence, and processing speed.

The Flynn Effect refers to the steady increase in average IQ scores over generations. Researchers attribute this trend to factors like improved education, nutrition, healthcare, and more cognitively stimulating environments.

IQ tests have been criticized for cultural bias, as test design may favor certain groups based on language, education, and socioeconomic background. While modern tests aim to minimize bias through culturally neutral questions and statistical adjustments, this remains an active area of research.

IQ can fluctuate, particularly during childhood and adolescence, due to factors such as education, environment, and brain development. IQ tends to stabilize in adulthood, though certain cognitive abilities may change with age.

• Fluid intelligence is the ability to solve new problems and think abstractly without relying on prior knowledge. It is associated with problem-solving and adaptability and typically declines with age.

• Crystallized intelligence is the ability to apply learned knowledge and experience, such as vocabulary and factual information. It often remains stable or even improves over time.

Online IQ tests vary in accuracy and reliability. Many are designed for entertainment rather than accurate cognitive assessment. It's best to take a professionally administered IQ test with standardized scoring for valid results.

Genetics significantly influences intelligence, but environmental factors, such as education, nutrition, and socioeconomic conditions, also shape cognitive development.

Ethical concerns include ensuring fairness, minimizing bias, protecting privacy, and using results responsibly. Misuse of IQ tests can lead to discrimination and social inequality.

Challenging your brain with activities such as puzzles, reading, and learning new skills can enhance cognitive abilities. Maintaining a healthy lifestyle, including exercise, proper nutrition, and sufficient sleep, also supports brain function.