Theories of Intelligence
- Spearman
- Thurstone
- Several hierarchical theories
- Developmental theories
- Information-processing and biological theories
Charles Spearman
- Developed the first formal theory of intelligence
- Based on the examination of the correlations between many tests of simple sensory functions
- Developed factor analysis
Spearman’s G
- Name came from correlations concluding that performance on tests were mostly dependent on one ‘g’eneral mental ability called g
- Each test also had specific variance ‘s’ and error variance
- Tests have a series of ‘s’ factors and one ‘g’ factor
S Factors
Specific abilities unique to certain tests or shared only by a subset of tests
Neuroimaging Support of Spearman’s Theory
- Tasks associated with ‘g’ consistently lead to activation of frontal lobes
- Dorsolateral prefrontal cortex mostly
- More difficult visuals more associated with ‘g’
- Remains a central concept in current intelligence theories
Thurstone’s Primary Mental Abilities (PMA’s)
- 60 tests administered to 240 males and extracted 9 interpretable factors (9 primary mental abilities)
- Believed correlations among different ability tests were low enough to conclude that they were measuring several largely independent factors
One Versus Many Debate
- Spearman emphasized overlap –> g versus Thurstone
- Thurstone emphasized separation –> multiple-factor theory
Hierarchical Models of Intelligence
- Search for compromise in the one versus many debate
- Many separate abilities, but they are arranged in a hierarchy with just one dominant factor at the top
- Separate factors
- A subordinate ‘g’
- Use more advanced factor analysis methods
Cattell and Horn’s Gf and Gc Theory
- Gf = fluid intelligence or raw potential
- Gc = crystallized intelligence or summation of learning
Fluid Intelligence (Gf)
- Raw potential (nature)
- Intellectual capabilities that have no specific content
- Used in processing information and approaching novel problems
Crystallized Intelligence (Gc)
- Summation of learning (nurture)
- Fund of information developed through experience, education, and practice
- Stored knowledge (vocabulary, general world facts)
7 Additional Factors at the Lower Hierarchical Level (Gf and Gc Theories)
- Short-term memory
- Long-term memory
- Visual processing
- Auditory processing
- Processing speed (on simple tasks)
- Decision speed (processing speed on more difficult tasks)
- Quantitative knowledge (mathematical reasoning)
Vernon’s Model
- Series of narrowly defined, specific capabilities that tend to cluster under a number or minor group factors
- Minor groups factors under two major groups (overall general mental ability such as Spearman’s ‘g’)
- v:ed is verbal:education
- k:m is spatial:mechanical
Carroll’s Theory
- Three striatum theory that is currently the best summary of all the hierarchical factor-analytic approaches to the definition of human intelligence
- Striatum I = specific, narrowly defined abilities that are factorially complex such as vision
- Striatum II = broad abilities such as Gf and Gc
- Striatum III = highest level, general intelligence such as spearman’s ‘g’
Developmental Theories
- How the mind develops with age and experience
- Three main characteristics include:
- Proceeds through series of stages
- Sequencing of stages must be invariant (everyone goes through them in the same order)
- Stages are irreversible
Sensorimotor Stage
- Birth to 2 years
- Limited sensory input
Preoperational Stage
- 2 to 6 years
- Uses words to symbolize
Concrete Operational Stage
- 7 to 12 years
- Uses principle of conservation
Formal Operational Stage
- 12+ years
- Mature adult thinking in terms of hypotheses (cause and effect)
- Abstract thought
- Theory of mind (thinking about others’ mental states)
Piaget Video
Take-away: kids’ brains aren’t just tiny adult brains
Information Processing Approach
- Intelligence is a process and not measurable quantity
- How instead of how much
- No ‘g’ factor
- Differences in cognitive operations of individuals
- 3 reliances: speed of processing, knowledge base, and acquiring/applying mental strategies
Speed of Processing
How rapidly a person can perform a mental task
Knowledge Base
Information stored in long-term memory
Ability to Acquire and Apply Mental Strategies
Can a person acquire and use new mental strategies?
