1. History: defining & measuring intelligence
Sir Francis Galton ( )
genes & family lines
intelligence = biological capacity
reaction times & sensory acuity
later research contradicted these measures
Photo of Francis Galton scanned in from Gray's text, pg. 356;
I like to discuss the eugenics controversy with my class when discussing Galton as well as his love of measurement & the bell curve

2. History: defining & measuring intelligence
Alfred Binet ( )
Binet-Simon Test France, 1905
intelligence = collection of higher-order mental abilities loosely related to one another
intelligence is nurtured
mental age
Photo scanned in from Gray's text, pg. 357

3. History: defining & measuring intelligence
Charles Spearman ( )
liked Binet’s methods of testing
liked Galton’s idea that intelligence was a single entity
developed “factor analysis”
two factors
“g” = general intelligence
“s” = specific ability
score on any given test depends on a combination of these 2 factors
g accounts for the similarity in test results
s accounts for the differences in test results

4. History: defining & measuring intelligence
Raymond Cattell ( )
student of Spearman’s
modified Spearman’s intelligence theory
thought that general intelligence was not one factor but two

5. Cattell’s Fluid & Crystallized Intelligence
Fluid intelligence
ability to perceive relationships without previous specific experience
matrices tests or verbal analogies
sample raven matrix problem scanned from Gray's text, pg. 360.
there are sample verbal analogies in Gray, pg. 360 that an instructor could use here
there are also other matrix tests that an instructor could include if desired

6. Cattell’s Fluid & Crystallized Intelligence
mental ability derived from previous experience
word meanings
use of tools
cultural practices

7. Modern intelligence tests
The Stanford-Binet Scale
modification of the original Binet-Simon, after original came to US
intelligence quotient (IQ) = child’s mental age divided by child’s chronological age
used widely in the US, not as much as previously

8. Modern intelligence tests
The Wechsler tests
used more widely now than Stanford-Binet
modeled after Binet’s, also made adult test
WISC-III for children
WAIS-III for adults

9. Standardized scoring of Wechsler tests
All raw scores converted to standardized scores
Normal distribution
Mean of 100
Standard deviation of 15
2.14%
13.59%
34.13%
0.13%
95.44%
68.26%
Wechsler IQ score
Number of score
figure taken from CD-ROM, Gray text, pg. 363, figure 10.5

10. How valid are IQ tests?
Validity = test measures what it’s intended to measure
Does test correlate with other measures of same construct?
School achievement
IQ tests (I.e., S-B and the Wechsler) correlate highly
but they were designed to test stuff that you learn in school
Prestigious positions
On-the-job performance & other work-related variables

11. What do IQ tests measure about your mind?
Mental speed and span of working memory
typically use a digit span test to measure this
more recent studies find significant correlations between reaction times and IQ scores
Why is this important?
mental quickness may expand capacity of working memory
I have already used digit span tests in my lectures during the memory chapter, but an instructor who has not done so may choose to include a demonstration of digit span/working memory here.

12. What do IQ tests measure about your mind?
Mental self-government
Sternberg
studies more complex decision-making abilities
states that the mind is made up of different components, each of which works on different problem solving tasks

13. Summary History of intelligence testing Modern intelligence testing
how did each figure define & measure intelligence?
Modern intelligence testing
Stanford-Binet vs. Wechsler tests
standardized scoring -- what is “average?”

14. Summary Validity of IQ tests What do IQ tests measure?
are they really measuring intelligence?
What do IQ tests measure?
mental quickness
mental self-government