流体和结晶智能理论提出有两种不同的智力。流体智能指的是在独特和新颖的情境中推理和解决问题的能力，而结晶智能指的是使用通过过去的学习或经验获得的知识的能力。该理论最初由心理学家Raymond B. Cattell提出，并与John Horn进一步发展。流体智能理论挑战了广义智能因子（称为g）的概念，它认为智能是一种单一的结构。相反，Cattell认为有两个独立的情报因素：“流动”或gf情报，以及“结晶”或gc情报。正如他在1987年出版的“情报：其结构，成长和行动”一书中所解释的那样，Cattell提到了之所以流动智能，是因为它“具有可以直接解决几乎任何问题的’流动’质量。”他将知识获取称为结晶智能，因为它“投资于结晶技能的特定领域，可以单独打乱而不影响“流体智能指的是推理，分析和解决问题的能力。当我们使用流体智能时，我们不依赖于任何已有的知识。相反，我们使用逻辑，模式识别和抽象思维来解决新问题。当我们遇到新的，通常是非语言的任务，如数学问题和谜题时，我们使用流体智能。流体智能也起到了作用。创造性的过程，就像有人拿起画笔或者在没有经过培训的情况下开始弹钢琴一样。流体智能植根于生理功能。结果，随着人们年龄的增长，这些能力开始下降，有时从20岁开始。
The theory of fluid and crystallized intelligence proposes that there are two distinct kinds of intelligence. Fluid intelligence refers to the ability to reason and solve problems in unique and novel situations, while crystallized intelligence refers to the ability to use knowledge acquired through past learning or experience. The theory was first proposed by psychologist Raymond B. Cattell and developed further with John Horn. The theory of fluid intelligence challenges the idea of generalized intelligence factor (known as g), which contends that intelligence is a single construct. Instead, Cattell contended that there are two independent intelligence factors: “fluid” or gf intelligence, and “crystallized” or gc intelligence. As he explained in his 1987 book Intelligence: Its Structure, Growth, and Action, Cattell referred to the ability to reason as fluid intelligence because it “has the ‘fluid’ quality of being directable to almost any problem.” He referred to knowledge acquisition as crystalized intelligence because it “is invested in the particular areas of crystallized skills which can be upset individually without affecting the others.” Fluid intelligence refers to the ability to reason, analyze, and solve problems. When we use fluid intelligence, we aren’t relying on any pre-existing knowledge. Instead, we are using logic, pattern recognition, and abstract thinking to solve new problems. We use fluid intelligence when we encounter novel, often nonverbal tasks, such as math problems and puzzles. Fluid intelligence also plays a role in the creative process, as when someone picks up a paintbrush or start plucking on a piano with no prior training. Fluid intelligence is rooted in physiological functioning. As a result, these abilities start to decline as people age, sometimes starting as early as their 20s.