Intelligence testing and theory link
Testing and Individual Differences
What the college board is asking for: This section of the course deals with the assessment of human differences in aptitudes, intelligence, and interests. It details the various types of tests used to assess these traits and the methods by which the tests are constructed. It describes the measures obtained from tests and the process of standardizing these measures. It treats the several ways of measuring the reiliability and validity of tests and explains the establishment and use of norms.
In this section of the course, students learn about the major theories pertaining to the structure intelligence: general versus specific-factor views of intellect. They also deal with the development of intelligence and consider the extremes of this trait: retardation and giftedness. Students are exposed to a number of controversial issues and interpretations related to the concept of intelligence: genetic versus environmental determinants, race differences, possible cultural bias in tests, and the use of measures of intelligence for the selection and placement of students in the educational system.
Finally, students confront the ethical issues that arise in connection with the use of tests, such as conflicts over the confidentiality of the information obtained on tests, problems in reporting the results of tests to the individuals who take them, the use of test scores for making comparisons among people, and the social impact of the use of tests.
Intelligence: (a very complex and controversial concept!) The general capacity to profit from experience, to acquire knowledge, and adapt to changes in the environment. According to this definition, an "uneduacated" street-smart kid in a poor section of town can be more intelligent than a math-whiz nerd who can seem "out of it" a lot of the time and not know which end's up. Intelligence is an innate cognitive ability that allows for acquisition of experience.
Dr. Howard Gardner felt that their are multiple intelligences. This proposes to find one's unique strengths, rather than come up with an IQ score.
Measurements of Intelligence
Early 1900's- Frenchman Alfred Binet and Theodore Simon created the first intelligence test to identify school children unable to benefit from traditional schooling (the Binet-Simon Scale)
Changed and refined at Stanford University by Dr. Louis Terman, it became the Stanford-Binet Intelligence Scale and is currently still being used today. The SBIS first used a ratio to indicate mental age vs. chronological age; this ratio is represented by the IQ score.
IQ is short for "Intelligence Quotient"...a "quotient" is a number; IQ is only a score measuring abilities that can be measured. There are so many abilities that we don't yet know how to "measure."
In 1912, German psychollogist, Dr. Wilhelm Stern developed the formula for determining IQ... a ratio between mental age (MA=the thinking/cognitive level) and the chronological age (CA=or actual years of age the person is currently) then multiplied by 100:
IQ=MA/CA X 100; for example, a 12 year old who performs on tests at the level of most 18 year olds, would have a CA of 12 and a MA of 18, and this ratio multiplied by 100 would produce an IQ score of 150.
Average IQ was established by giving thousands and thousands of test to thousands and thousands of people. The vast majority of 8 year olds performed to a certain level on all tests, etc. Therefore, that score that the vast majority performed at for an age level became "100", and therefore an IQ of 100 is considered average.
If a child performed slightly above what was generally expected for a 12 year old, then the Menatl Age (MA) was slightly higher than the chronological age (CA) and the ratio multiplied by 100 would produce an above average score. But it is still just a score and it does not account for everything. It can chage over time, though it seems to be pretty stable within a range of +/- 5 points or so.
50% of the population has an IQ between 90 and 110. 1% of the population receives an IQ score above 145. Genius is generally 180 of above, the highest recorded score is 230. Retardation is an IQ of below 70.
Weschler Intelligence Scale (WAIS)
The striking difference between the Stanford-Binet and the Weschler is that the Weschler alerts the examiner to possible learning problems. For example, a verbal score much lower than the same person's performance score might indicate a reading or language disability.
Reliability and Validity of Intelligence Tests
Reliability: A good test must yield dependably consistent scores. To check this, researchers must retest people using either the same test or another form of it. If the scores agree, or correlate, the test is reliable. The Stanford-Binet and WAIS have a +.9, which is awesome.
Validity: The extent to which the test actually measures what it is suppossed to measure or predicts what it is supposed to predict. The big question is: Are general aptitude tests as predictive as they are reliable? The answer is simply NO! The SAT used in the U.S. as a college entrance exam, is not successful in predicting first year college grades; here, the correlation is +.5. The GRE (a similar test as SAT for graduate school), the correlation with graduate school grades is +.30. So why do we use them? Ask me in class and I will give you a good answer. I promise.
Genetic and Environmental Influences
Genetic: Wow, does this subject arouse passion! Here are some examples to suppport genetic influence on intelligence. 1) Intelligence scores of 163 identical twins reared together are virtually as similar as those of the same person taking the same test twice (Lykken, 1999). 2) Twin studies of twins reared apart lead researchers to believe intelligence is 70% attributed to genetic variation (Plomin 1999). 3) An intelligence gene on chromosone 6 has been identified (Chorney, 1998) 4) By inserting an extra gene into ferilized mouse eggs, researchers can produce smarter mice (Tsien, 2000).
Environmental: One name, Richard Feynman, tells it all. A physicist who won the Noble Prize with a 124 IQ. Well of course environment plays a roll, because infants that are malnurished, sensory deprived and socially isolated are at a greater disadvantage then those that are not. Orphanage studies greatly support the importance of the environment. J. Hunt in 1982 used early intervention techniques to boost the language development of orphans in Tehran. These children couldn't talk or walk at 2 and even 4 years of age, however through a program of vocal games the infants had unprecedented success in language development.