Related Experiment Video
Updated: Aug 5, 2026
10:33
Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury
Published on: August 14, 2019
Fluid and crystallized intelligence: effects of diffuse brain damage on the WAIS
Perceptual and Motor Skills
|August 1, 1980
Summary
Fluid and crystallized intelligence, proposed in the 1940s, were studied using the Wechsler Adult Intelligence Scale (WAIS). Brain damage impacted crystallized (verbal) abilities more than fluid (performance) abilities, contrary to hypotheses.
Area of Science:
- Neuropsychology
- Cognitive Psychology
- Psychometrics
Background:
- Theories of intelligence distinguish between fluid abilities (active processing) and crystallized abilities (learned knowledge).
- The Wechsler Adult Intelligence Scale (WAIS) differentiates between performance (fluid) and verbal (crystallized) subtests.
- Brain damage is hypothesized to differentially affect these intelligence forms.
Purpose of the Study:
- To investigate the differential impact of diffuse organic brain damage on fluid and crystallized intelligence.
- To compare WAIS performance and verbal subtest scores in normal versus brain-damaged individuals.
Main Methods:
- Utilized the Wechsler Adult Intelligence Scale (WAIS) to assess cognitive functions.
- Compared scores on performance subtests (fluid intelligence) and verbal subtests (crystallized intelligence).
- Analyzed data from subjects with normal cognitive function and those with diffuse organic brain damage.
Main Results:
- WAIS verbal subtests, reflecting crystallized intelligence, showed greater impairment in brain-damaged subjects.
- WAIS performance subtests, reflecting fluid intelligence, were less affected than verbal subtests.
- Findings indicated a significant impact of organic brain damage on crystallized abilities.
Conclusions:
- Diffuse organic brain damage disproportionately affects crystallized intelligence compared to fluid intelligence.
- The WAIS can be a valuable tool for assessing the cognitive sequelae of brain injury.
- Results challenge previous assumptions about the selective vulnerability of fluid abilities to brain damage.
Related Concept Videos
01:27Language and Cognition
Language serves as a bridge between ideas and communication, influencing how individuals perceive and interact with the world. Psychologists have long debated whether language shapes thought or vice versa. This discussion gained grip with Edward Sapir and Benjamin Lee Whorf in the 1940s, who proposed that language determines thought, a concept known as linguistic determinism. They suggested that the vocabulary and structure of a language influence how its speakers think and perceive reality.
01:25Cattell's Theory of Intelligence
Raymond Cattell, along with John Horn, made significant contributions to our understanding of intelligence by distinguishing between two types: fluid intelligence and crystallized intelligence.
Fluid intelligence involves the capacity to solve new problems and adapt to unfamiliar situations. It's the type of intelligence individuals use when they encounter a novel problem or puzzle that requires innovative thinking. For instance, figuring out how to operate a new gadget relies heavily on fluid...
Fluid intelligence involves the capacity to solve new problems and adapt to unfamiliar situations. It's the type of intelligence individuals use when they encounter a novel problem or puzzle that requires innovative thinking. For instance, figuring out how to operate a new gadget relies heavily on fluid...
01:23Wechsler's Contribution to Measures of Intelligence
David Wechsler, a psychologist who worked with World War I veterans, developed a significant IQ test in 1939 called the Wechsler-Bellevue Intelligence Scale. This test was innovative because it combined several subtests that measured both verbal and nonverbal skills, reflecting Wechsler's belief that intelligence is a global capacity involving purposeful action, rational thinking, and effective interaction with the environment. This test later evolved into the Wechsler Adult Intelligence Scale...
01:30Biological Influences on Intelligence
Intelligence is often thought to be linked to brain size, but the relationship is more complex than that. While brain size does correlate modestly with some abilities, like verbal skills, the connection is weaker for others, such as spatial reasoning. Other factors, like brain structure, also play crucial roles. For instance, despite Einstein's smaller-than-average brain, his parietal cortex, which is involved in spatial reasoning, was 15% wider, suggesting that neural density might matter more...
01:30Cognitive Development During Adulthood
Cognitive development continues throughout adulthood, undergoing significant shifts across early, middle, and late stages. Individual transition occurs from adolescent idealism to pragmatic and adaptable thinking in early adulthood. During this period, individuals learn to integrate personal beliefs with the recognition that other perspectives are equally valid. Exposure to the complexities of modern society, diverse experiences, and higher education contribute to this adaptive thought process,...
01:22Cerebral Edema ll: Pathophysiology
Vasogenic edema is a major form of cerebral edema characterized by abnormal accumulation of fluid in the brain’s extracellular space due to disruption of the blood–brain barrier (BBB). The BBB is a specialized structure composed of endothelial cells connected by tight junctions, supported by astrocytic endfeet and a basement membrane. Under normal conditions, it tightly regulates the movement of ions, proteins, and solutes between the bloodstream and brain parenchyma. When this barrier loses...