From Binet's work, the phrase "intelligence quotient," or "IQ," entered the vocabulary. The IQ is the ratio of "mental age" to chronological age, with 100 being average. So, an 8 year old who ...

Many online IQ tests come across as little more than digital parlor tricks. Users often end up with vague, unverified results. In other cases, the platforms tell people what they want to hear.