SPEARMAN'S TWO-FACTOR THEORY (Charles Spearman, 1904): Intelligence consists of two factors: (a) 'g' FACTOR (General Intelligence) — present in ALL mental activities. A person with high 'g' performs well across various tasks. It's innate and relatively fixed. (b) 's' FACTOR (Specific abilities) — unique to particular tasks (mathematical ability, verbal ability, musical ability). Every mental activity involves BOTH 'g' and 's'. Example: solving a math problem requires general intelligence (g) + specific mathematical ability (s). Spearman used FACTOR ANALYSIS (statistical technique) to identify these factors. Criticism: oversimplifies intelligence into just two factors.

THURSTONE'S PRIMARY MENTAL ABILITIES (L.L. Thurstone, 1938): Rejected Spearman's single 'g' factor. Proposed 7 PRIMARY MENTAL ABILITIES: (1) Verbal Comprehension (understanding words), (2) Word Fluency (producing words quickly), (3) Number Facility (arithmetic), (4) Spatial Visualization (mental rotation), (5) Associative Memory (recalling paired items), (6) Perceptual Speed (quick pattern recognition), (7) Reasoning (finding rules/patterns). Thurstone argued these are INDEPENDENT — a person can be high in verbal but low in spatial. Later research showed these 7 abilities ARE correlated, supporting a modified 'g' factor.

GUILFORD'S STRUCTURE OF INTELLECT (J.P. Guilford, 1967): A three-dimensional model creating 180 distinct intellectual abilities (later revised to 150). Three dimensions: (1) OPERATIONS (what the mind does): Cognition, Memory Recording, Memory Retention, Divergent Production, Convergent Production, Evaluation. (2) CONTENTS (type of information): Visual, Auditory, Symbolic, Semantic, Behavioral. (3) PRODUCTS (form of information): Units, Classes, Relations, Systems, Transformations, Implications. Each cell (Operation × Content × Product) = one ability. Most famous contribution: distinction between CONVERGENT THINKING (finding one correct answer) and DIVERGENT THINKING (generating multiple creative solutions) — crucial for understanding creativity.

STERNBERG'S TRIARCHIC THEORY (Robert Sternberg, 1985): Intelligence has THREE aspects: (1) ANALYTICAL (Componential) — academic problem-solving, test-taking ability, critical thinking. Measured by traditional IQ tests. (2) CREATIVE (Experiential) — dealing with NOVEL situations, insight, invention. Ability to handle new tasks and automate processes. (3) PRACTICAL (Contextual) — 'street smarts', adapting to real-world environments, common sense. Knowing WHAT works in a given situation. Sternberg argued traditional IQ tests measure ONLY analytical intelligence, ignoring creative and practical — which are equally important for success in life.

GARDNER'S MULTIPLE INTELLIGENCES (Howard Gardner, 1983): Originally proposed 7 intelligences, later added 2 more = 9 TYPES: (1) LINGUISTIC — language, reading, writing (authors, poets). (2) LOGICAL-MATHEMATICAL — reasoning, numbers, patterns (scientists, mathematicians). (3) SPATIAL — mental imagery, maps, art (architects, pilots). (4) MUSICAL — rhythm, pitch, melody (musicians, composers). (5) BODILY-KINESTHETIC — body control, coordination (athletes, surgeons). (6) INTERPERSONAL — understanding others, social skills (leaders, teachers). (7) INTRAPERSONAL — self-awareness, self-reflection (philosophers, monks). (8) NATURALISTIC (added 1995) — understanding nature, classification (biologists, farmers). (9) EXISTENTIAL (proposed) — pondering life, death, existence. EDUCATIONAL IMPACT: Each child may be strong in different intelligences — teaching should use MULTIPLE APPROACHES to reach all learners.

CATTELL'S FLUID AND CRYSTALLIZED INTELLIGENCE (Raymond Cattell, 1963): Two types: (a) FLUID INTELLIGENCE (Gf) — ability to reason abstractly, solve novel problems without prior knowledge. DECLINES with age (peaks in early 20s). Examples: pattern recognition, logical puzzles, adapting to new situations. (b) CRYSTALLIZED INTELLIGENCE (Gc) — accumulated knowledge, vocabulary, facts learned through education and experience. INCREASES with age (keeps growing throughout life). Examples: vocabulary size, general knowledge, professional expertise. IMPORTANT: Cattell ALSO developed the 16 PF (Personality Factor) Questionnaire using factor analysis — this measures personality TRAITS, not intelligence. 16PF identifies 16 source traits in opposing pairs (warm vs reserved, abstract vs concrete, etc.). Frequently confused with his intelligence theory in REET (Q.71 PQR paper asked who developed 16PF → answer: Raymond Cattell).

PASS MODEL (Das, Naglieri, and Kirby): PASS stands for Planning, Attention, Simultaneous processing, Successive processing. Based on Luria's neuropsychological model. Planning = strategy formulation, Attention = selective focus, Simultaneous = seeing patterns as wholes, Successive = processing in sequence. HIERARCHICAL MODEL (Arthur Jensen): Two levels — Level I (Associative/rote learning, memorization) and Level II (Cognitive/abstract reasoning). EMOTIONAL INTELLIGENCE (Daniel Goleman, 1995): EQ = ability to recognize, understand, manage own emotions AND perceive others' emotions. Five components: Self-awareness, Self-regulation, Motivation, Empathy, Social skills. Goleman argued EQ is MORE important than IQ for success in life and leadership.

IQ MEASUREMENT: BINET-SIMON SCALE (Alfred Binet & Theodore Simon, 1905, Paris): First practical intelligence test. Developed to identify children needing special education. Introduced concept of MENTAL AGE (MA). STANFORD-BINET (Lewis Terman, Stanford University, 1916): Revised Binet's test for American use. Introduced IQ formula by William STERN: IQ = (Mental Age / Chronological Age) × 100. Example: 8-year-old with MA of 10 → IQ = (10/8)×100 = 125. WECHSLER SCALES: David Wechsler developed: WAIS (Wechsler Adult Intelligence Scale) and WISC (Wechsler Intelligence Scale for Children). Introduced DEVIATION IQ — comparing individual to age-group norm (mean=100, SD=15). WAIS-R has two parts: VERBAL subtests (Comprehension, Arithmetic, Similarities, Information, Digit Span, Vocabulary) and PERFORMANCE subtests (Object Assembly, Digit Symbol, Picture Completion, Block Design, Picture Arrangement). Q.77 PQR tested which are verbal subtests.

REET EXAM TIPS (8-10 questions): MATCHING FORMAT dominates: theorist↔theory name. (1) Spearman=Two-Factor (g+s), Thurstone=7 Primary Mental Abilities, Guilford=SOI/180 abilities/Divergent-Convergent, Sternberg=Triarchic (Analytical+Creative+Practical), Gardner=Multiple Intelligences (9 types), Cattell=Fluid+Crystallized, Das/Naglieri/Kirby=PASS, Jensen=Hierarchical, Goleman=Emotional Intelligence. (2) Cattell's 16PF = PERSONALITY test (not intelligence — confirmed Q.71 PQR). (3) IQ formula: MA/CA × 100. (4) WAIS-R verbal subtests: Comprehension, Arithmetic, Similarities (not Object Assembly or Digit Symbol — those are performance). TRAPS: '16PF is an intelligence test' — FALSE (personality). 'Gardner proposed 7 intelligences' — MISLEADING (originally 7, now 9). 'Fluid intelligence increases with age' — FALSE (decreases; crystallized increases). 'Sternberg's model has 4 parts' — FALSE (3: Analytical, Creative, Practical).