Intelligence Flashcards
(365 cards)
Who is Samuel George Morton? What year was he in? How did he measure intelligence? Why did he measure intelligence? What were his conclusions?
• Samuel George Morton
o 1839-1850
o Used skull capacity as a measure of mental worth (Craniology)
Looked at skulls he collected from North and South America
o Primary agenda was to validate known groups differences (and therefore served continuance of slavery)
That white males are the smartest of all groups
o Originally used mustard seeds to estimate volume of skull (filled up upside down skull to measure mustard seeds)- later went to 1/8 inch diameter lead shot (ball bearings)
Found that mustard seeds were not reliable as they could be squished
o He published all of his data (did not hide his tracks)
o Concluded that volume of Caucasian skull (87 inches cubed) was higher than that of Ethiopian (78 inches cubed)– thought that he had measured an innate difference in intelligence
This confirmed pre-existing biases that white men were superior
What were problems with Samuel George Morton’s data?
Made no attempt to externally validate the measure
Failed to take into consideration stature and gender of the individuals
• Size of brains are related to size of bodies
Selective in way he would include or exclude data
• If he saw that there was large brain from non-white group, he would find a reason to exclude it from dataset
Prior prejudice
• Measure with mustard seed was imprecise (high measurement error)
• On re-measurement with lead shot- discrepancy favoured a priori expectations
o Underestimation of skulls for blacks by 5.4 cubic inches
o Underestimation of Indian skulls by 2.2 cubic inches
o underestimation of white skulls by 1.8 cubic inches
Who was Paul Broca inspired by and why did he measure intelligence the way he did?
• Paul Broca
o Followed Morton’s work but added much more precision
o Took various skull measures
Cranial index: ratio of length to width
Brain weight (where possible)
o Support Morton’s group findings with copious numbers
o However, when it was suggested to him that brain size bore no relation to degree of intelligence, he said that the study of the brains of human races would lose most of its interest and utility if variation in size counted for nothing
Argued that anthropologists spent so much time measuring skulls because their results could be used to delineate human groups and assess their relative worth
Who was Le Bon and what did he do?
• Le Bon used Broca’s data to support pre-existing prejudice in group differences in 1879
o Used small skull of women to prove women’s inferiority
Who was Galton and how did he test intelligence? What were the shortcomings of this method? What did he contribute to the scientific community?
• Galton, late 1800s
o Hereditary genius (1869)
o Physical measurement of intelligence (from 1880s onwards)
o Tests of:
Sensory acuity
Head size, strength
Speed of reactions
o Tests showed little relationship to any external criteria associated with intelligence (how successful people were at work…), or with each other
o Galton’s legacy
Scientific/empirical approach to human intelligence
Statistical methods (invented normal curve, correlation) with Pearson
Observed normal curve
Study of nature versus nurture (twin studies and heritability)
Why did Binet (1905) disagree with Broca’s method?
• Binet-1905
o Binet had problems with Broca’s method
Couldn’t demonstrate external validity: needed a more objective method
How did Binet view intelligence?
o Binet considered intelligence to consist of different abilities and to be dependent on a variety of higher psychological faculties, such as attention, memory, imagination, common sense, judgement and abstraction
What is the objective of the Binet-Simon scale, why was it developed and how did it work?
o Commissioned by the French government that would identify students that were not succeeding and that should be offered special education
o Binet-Simon scale
Set out to develop a set of measures that form the basis of intelligence test as we know them today
Age level assigned at each task
Mental age assigned to the person
o Objective-
Identify children whose lack of success in normal classrooms suggested the need for some form of special education
o Did not test for knowledge acquired in classroom
What is task age in the Binet-Simon scale?
• The youngest age at which a child of normal intelligence should be able to complete the task
What is mental age and what are problems with using it as a standard for intelligence?
Mental age assigned to the person
• Age level at which normal children in the standardisation sample passed the task
• Problem with mental age
o Hard to make comparisons across people of different ages
Who was the Binet-Simon scale intended for?
o Binet was very explicit in stating that the scores derived from his tests were rough, that they were not intended for use in ranking normal children, and above all else, they were indicators of current functioning and did not speak to the past or future capabilities of the child
Describe how the US army used tests of intelligence and why
• Army Alpha and Army Beta
o Group-administered tests of intelligence
Literate people first administered alpha test
Illiterate, or people who failed the alpha were to get the Beta non-verbal test
Individuals who failed the beta test were to be individually tested
o Wanted to know who would be in the front lines and who would be officers
What was the Stanford-Binet test used for?
• Stanford-Binet
o Used initially to detect feeble minded school children
o Subsequently used in adult populations
Stop not smart people from entering the country-test immigrants arriving in New York and only intelligent people were allowed to immigrate
Stop people who were not smart from reproducing (eugenics movement)
Describe Stanford-Binet test classifications for adults
o Classification for adults: Idiots- mental age <2 Imbecile- mental age (3-7) Feeble-minded: mental age (8-12) Moron: Highest functioning mentally retarded
What did Lewis Terman (1916) do?
Revised and published Binet’s test as the Stanford-Binet
Developed and publicised intelligence testing as measurement
-Used ratio-IQ
Who first proposed and adapted Ratio IQ?
• First proposed by William Stern (1912), adopted by Terman
What was the mental age of white americans?
16 years old
What is ratio-IQ?
ratio IQ= Mental Age/Chronical Age * 100
What are problems with ratio IQ and what was a temporary solution for this?
• Problem with ratio IQ-
o Only works if mental age increases proportionally with chronological age. Difficulty to say anything substantiative about adults
As get older, intellectual ability does not increase with chronological age
o Hence, decided that cut- off mental age was 16, but still not good solution
Who developed deviation IQ?
David Wechsler
What is deviation IQ?
How much you deviate from the mean performance of a comparison group
Related to the idea of norm-referenced testing used throughout psychology
Judge a person’s test score in terms of how it compares to an appropriate standardization sample
What is the advantage of deviation IQ?
• IQ scores means the same thing regardless of the comparison group
What is the mean and standard deviation of deviation IQ?
o IQ= 100 means you are average, SD=15
Why is the mean for deviation IQ 100?
o 100 was set as the average to be consistent with the ratio IQ which was familiar to psychologists