Why has intelligence historically been so difficult to define?
What is intelligence
- Three definitions from Merriam-Webster dictionary:
- (1)the ability to learn or understand or to deal with new or trying situations
- (2)mental acuteness, shrewdness
- (3)the act of understanding
Early definitions of intelligence
- “the tendency to take and maintain a definite direction; the capacity to make
- adaptations for the purpose of attaining a desired end” (Binet).
“the ability to educe either relations or correlates” (Spearman).
- “adjustment or adaptation of the individual to his total environment,” “the ability to
- learn,” and “the ability to carry on abstract thinking” (Freeman).
Prior to Binet, what were some general problems with early scales designed to measure ability or intelligence (e.g., Cattell)?
Has remained unchanged for 60 years; outdate
scale measures is unclear; it does not predict future intelligence for infants in the normal ranges.
Scale sample is based primarily on children ofparents from the lower and middle classes and therefore does not represent the general population
What were the two major innovations of the first Binet-Simon scale?
Why were they important?
- •age differentiation-refers to the simple fact that one can diff erentiate older children from younger children by the former’s greater capabilities. For example, whereas most 9-year-olds can tell that a quarter is worth more than a dime, a dime is worth more than a nickel, and so on, most 4-year-olds cannot. In employing the principle of age diff erentiation, Binet searched for tasks that could be completed by between 66.67% and 75% of the children of a particular age group and also by a smaller proportion of younger children but a larger proportion of older ones. Th us, Binet eventually assembled a set of tasks that an increasing proportion of children could complete as a function of increases in age. Important: one could determine the equivalent age capabilities of a child independent of his or her chronological age. Th is equivalent age capability was eventually called mental age.
- •general mental ability-measure only the total product of the various separate and distinct elements of intelligence, that is, general mental ability. With this concept, Binet freed himself from the burden of identifying each element or independent aspect of intelligence.
- These concepts still underlie today’s major theories of intelligence
James Catell (1890) developed
•Proposed a battery of 10 tasks he believed to be associated with mental ability.
•Dynamometer pressure Rate of Movement
•Sensation Areas Judgment of 10 sec.
•Time for Naming Colors Bi-section of 50 cm line
Reaction Time for Sound
appointed in early 1900’s to develop procedure for identification of “subnormal” children
•early definition based on idea that intelligence was evident through:
What is Spearman’s concept of g? Based upon this concept, how would one best
encapsulate general ability or intelligence (e.g., one score, multiple)?
empirical support for general mental ability factor underlying all intelligent behavior
•general factor = “g”
•large # of more specific factors
•all tests, no matter how diverse, are influenced by g
Developed statistical technique “factor analysis” to provide support for g.
•any common variance noted among factors represents the g factor.
•evidence = positive correlations
Implications of g
Person’s intelligence can best be represented by a single score.
•any noted differences in terms of unique abilities/weaknesses cancel each other out
•overall performance on set of tasks depends heavily on the general factor
How did the Horn-Cattell model of intelligence differ from Spearman?
Horn-Cattell Gf-Gc theory of intelligence
- •their analyses did not readily identify a “g” factor
- •suggested human intelligence better represented in multiple forms rather than a single
- Initially proposed two types:
- (1)fluid intelligence (Gf)
- (2)crystallized intelligence (Gc)
What are some of the distinguishing characteristics of Gf-Gc theory?
Two are distinguished by the ability to learn (Gf) and learning that has already occurred (Gc)
- Fluid intelligence (Gf)
- •those abilities that allow us to reason, think, and acquire new knowledge
- •materials or processes are typically new to person
- Crystallized intelligence (Gc)
- •knowledge and understanding that has already been acquired
- •applicationof acquired knowledge and learned skills to answering questions
- •may include measures of general knowledge and vocabulary
With regard specifically to the 1937 edition of the Stanford-Binet, what was the primary interpretive issue that was deemed to be problematic?
- 1937 scale – improved standardization sample
- •mental age increased to 22 yrs, 10 mo.
- •decreased emphasis on verbal skills
- •alternate forms (L and M) were published
- •problem– lack of uniform standard deviation at different age levels
8-9 broad abilities GF GC
- Gv - Visual Intelligence
- SAR – Short-Term Acquisition and Retrieval (Gsm)
- Ga – Auditory Intelligence
- TSR – Long-Term Storage and Retrieval (Glr)
- Gs – Cognitive Processing Speed
- CDS – Correct Decision Speed
- Gq – Quantitative Knowledge
- Grw – Reading and Writing Skills
Caroll's 3 Stratum Theory
- 1993 – John Carroll’s book Human Cognitive Abilities: A Survey of Factor Analytic Studies
- •reviewed and reanalyzed 461 data sets post-1925
- •book is considered a seminal work in area of human cognitive ability
•proposed“Three Stratum” model of intelligence based upon extensive data analyses
- Stratum III = general intelligence factor
- •broadest level of intelligence •conceptually similar to Spearman’s “g”
- Stratum II – 8 broad abilities
- •represent “basic constitutional and long-standing characteristics of individual”
- •can “influence a great variety of behaviors”
- Gf – Fluid Intelligence
- Gc – Crystallized Intelligence
- Gy – General Memory and Learning
- Gv – Broad Visual Perception
- Ga – Broad Auditory Perception
- Glr – Broad Retrieval Ability
- Gs –Broad Cognitive Speediness
- Stratum I – 69 narrow abilities
- •measures of specific human abilities
- •these abilities subsumed by 8 Stratum II abilities, which in turn are subsumed by the single Stratum III “g” factor
Gt – Reaction Time/Decision Speed
Differances between Cattell & Carol's Theories
- •Carroll’s Stratum II abilities very similar in nature to Gf-Gc
•Stratum I abilities reported by Carroll also similar to those suggested by Horn
- Primary difference between 2 theories = the existence of g?
- Empirical evidence supports a combined CHC theory
The 1960 scale introduced the concept of “deviation IQ.” What does this mean?
- 1960 scale-introduced “deviation IQ” scale
- •set mean and SD at 100 and 16, respectively across all age groups
- •method still used today, considered most precise way of expressing the results of an
- intelligence test
- •today, most tests – mean = 100, std dev = 15
- First edition – Binet-Simon scale (1905) developed to identify mentally challenged children in Paris school system.•30 items, increasing in difficulty•examples:•#4 – recognize food items (e.g.,chocolate vs. wood)•#9 – designate objects in a picture
- •Binet believed this item was approx. limit of avg 3-yr-old
- 1908 – included age scale •items grouped according to age level•2/3 – 3/4 of items correct to move to next level
- •scale only produced one score•highly tied to verbal, language,and reading ability•concept
- of “mental age” introduced here
- Stanford-Binet Intelligence Scale (1916)
- •developed by Terman at Stanford U.•standardization sample consisted almost entirely of whitechildren from CA.•introduced concept of “intelligence quotient” (IQ)alculated by dividing subject’s chronological age into his/her obtained mental age, multiplying by 100.
- •this method ultimately abandoned – scale had maximum mental age of 19.5 years
- 5th Edition Published in 2003
- •=weighting of verbal, nonverbal tasks
- •2“routing tests” (1 verbal, 1 nonverbal) organized in a point scale (i.e., items
- increase in difficulty)
- •these tests estimate examinee’s level of ability•administration of other tasks
- (and level of difficulty at which to begin) depends on performance from routing