 There are arguably two types of intelligence. Fluid intelligence is your ability to reason quickly and independently of your past experiences. It relies on the ability to hold attention and benefits from a strong working memory. While it can be trained, fluid intelligence is mainly determined by your genes. Crystallized intelligence is your ability to apply knowledge from prior learning that was stored in your long-term memory. It increases with experience and is hence mostly formed by the environment. To solve complex problems, both types of intelligence need to work together. To illustrate how fluid and crystallized intelligence work, let us tell you the story of Arthur, a fine young man who wants to save a young princess that was captured by an evil witch. The witch promised to release the princess only if Arthur brings her a precious jewel from a secret tomb. Arthur agrees, begins his quest, and comes across a deep, dark forest that he must cross. He navigates through the wilderness with a compass and a map, using the intelligence he crystallized when he spent lots of time studying maps as a boy. At the end of the forest, Arthur discovers the entrance to the tomb and sees the prized jewel already sparkling in the distance. As he enters the tomb, he steps on a pressure plate. His crystallized intelligence tells him that this is a mechanical trap, something he learned about earlier in life. He stands still and thinks of a solution. Since he has never been in the situation before, he cannot draw on past experience. Thankfully, his fluid intelligence takes over and allows him to make a new plan on the fly. Drop the bag. It puts pressure on the plate and you can grab the jewel. Crystallized intelligence takes note for future reference. Arthur then gave the jewel to the witch, freed the princess, and brought her safely back home. Suppose Arthur was an average child and we were able to plot the development of his intelligence over 90 years. His fluid intelligence would increase sharply until his early 20s and then peak and decline. His crystallized intelligence would peak later and slowly decline at a higher age. The psychologist Raymond Cattle coined the terms fluid and crystallized intelligence in 1963. To learn how it works and download this video without ads or background music, check out our website or read the description below. If you want to support our mission and help change education, visit our Patreon. That's patreon.com slash sprouts.