Psychometric Chapter 9: Theories of intelligence & the Binet Scale

Spearman's Mode of General Mental Ability

*Charles Spearman- All intelligent behavior rests on a foundation of general mental ability (g). - g is believed to be composed of several s factors -Positive manifold' *Spearman developed factor analysis to reduce many items to common factors. -A very important statistical technique still in use. *g is still regarded as an important predictor of performance in a number of contexts.

The Early Binet Scales- The 1905 Binet-Simon Scale

- 30 items of escalating difficulty - Intellectual deficits were defined with unpleasant terms: * Idiot (most severe) * Imbecile (more moderate) * Moron (mild impairment) -Binet identified exactly what he wanted to measure and developed items for that purpose. -It lacked an adequate measuring unit as well as normative data or validity evidence.

Terman's 1916 Stanford-Binet Intelligence Scale

- Lewis Terman relied heavily on Binet's earlier work. -Mental age was also retained as a concept. (Principles of age differentation, general mental ability and, age scale. Mental age concepts) -Standardization sample was increased, though the sample was, however, very lacking in adequate diversity.

The gf-gc Theory of Intelligence

- One of the earliest theories of multiple types of intelligence. - Diverged from the g theory of Spearman - gf= fluid intelligence *Abilities related to reasoning, thinking, and gaining new knowledge (the ability to learn) - gc= crystallized intelligence * Previously acquired knowledge as well as understanding of it ( what you've already learned).

The Intelligence Quotient (IQ)

- Stern (1912) proposed the formula for calculating IQ. - IQ was calculated as a ratio of one's mental age to his/her chronological age * IQ=(MA/CA)X100 * MA= Mental age * CA= Chronological age -When one's MA and CA are equivalent, IQ comes to 100. This represents an "average" IQ. -Major limitations was that it artificially lowered IQ as one got older, and this formula is no longer in use.

The 1908 Scale

- Was an age scale that retained the notion of age differentiation. (Retained principle of age differentiation) - This age scale had limitations that were not fully overcome until the 2003 edition. (Used age scale format) - Introduced concept of mental age, but still expressed intelligence in terms exclusively related to linguistic skills. (Introduce concept of metal age)

Characteristics of the 1986 Revision

-Attempted to retain strengths and reduce weaknesses of earlier editions. Age scale format was eliminated -Separate tests with similar items created

The Modern Binet Scale-Model for the Fourth and Fifth editions

-Continued use of psychometric and theoretical concepts. -Went beyond Spearman's g model and incorporated the gf-gc model: *g is at top of model *Second level ad three components: 1. Crystallized abilities 2. Fluid-analytic abilities 3. Short-term memories -The role of Thurstone's multidimensional model *Primary mental abilities

The 1937 Scale

-Extended age range down to 2-year-old level -Increased maximum possible mental age up to 22 years, 10 months. -Scoring standards and instructions were improved. -Standardization sample was improved. -Alternate equivalent forms (L and M) were also designed. -Problems: *Reliability coefficients not equal for different ages. *Different age groups in standardization sample produced unique deviation IQ scores.

Characteristics of the 2003 Fifth Edition

-Integrated age-scale and point-scale measures. -Verbal and nonverbal routing measures(IQ). -Start points, basal, and ceiling.

Implications of General Mental Intelligence (g)

-Overall intelligence is best represented by a single underlying factor (g). -This factor represents the shared variance underlying performance on a diverse set of tests. -It is possible that both g as well as other more specific skills underlie scores on a given test. -g was a driving force in the development of the Binet scales.

Psychometric Properties of the 2003 fifth edition

-Standard deviation changed to 15, while mean of 100 retained. -Age range from 2 to 85+ years -Standardization sample again increased and more diverse. -Reliability is quite good. -Some research challenges the claim that the fifth edition measures five distinct factors.

The 1960 Stanford-Binet Revision and Deviation IQ (SB-LM)

-Tried combining best forms of 1937 scale -Tasks were selected based on best qualities from earlier edition. -Used deviation IQ (mean of 100 and SD of 16) -New IQ tables reflected performance on scores, age, and percentiles. -Did not have new standardization sample, but one was created by 1972. -Additional revisions in 1987 and 2003 attempted further improvements.

Binets 3 components of intelligence

1. To find and maintain a definite direction and purpose. 2. The ability to make necessary adaptations 3. To engage in self-criticism and adjustments in strategy.

Standardized intelligence tests

Began within a 1904 effort in France- enter Alfred Binet

Spearman's model of intelligence

Intelligence can be viewed in terms of one general underlying factor (g) and a large number of specific factors (S1, S2, ...., Sn). Intelligence can be viewed in terms of g (general mental ability) and S (specific factors). Spearman's theory was consistent with Binet's approach to constructing the first intelligence test.

Binet's Principles of Test Construction

Principle #1: Age differentiation -One can differentiate kids of different ages by their ability levels. -Assess the mental abilities of different aged children. Principle #2: General mental ability -Binet sought to measure the total product of various separate and distinct elements of intelligence.

Different approaches to psychology

Psychometric, Information-processing and Cognitive tradition