Book Definition: A general ability, proposed by Spearman as the main factor underlying all intelligent mental activity.


In the 1920s, intelligence tests became more prevalent. The British psychologist Charles Spearman showed a high correlation between test taker's scores on varied tests. He called this general intelligence and later named it the g factor. John Duncan later on, developed the insight that the frontal lobe could be the center of the g factor.

In Your Own Words

  • A well-rounded person (mentally).


  • Someone who is smart and generally knowledgeable in a variety of topics.
  • The IB program would best support the g-factor theory because it requires specific advanced placement classes in 6 areas of generic subjects such as art, music, math, english, history, and science, expecting you to achieve an A.

Additional Resources