lecture 11 from a college level introduction to psychology course taught Fall 2011 by Brian J. Piper, Ph.D. (firstname.lastname@example.org) at Willamette University, includes Binet, Terman, Wechsler, WAIS, reliability, validity, norms
Preview Question 1: When and why were intelligence tests created?
Preview Question 2: What’s the difference between aptitude and achievement tests, and how can we develop and evaluate them?
Preview Question 3: How stable are intelligence scores over the life span?
Preview Question 4: What are the traits of those at the low and high intelligence extremes?
Introductory Psychology: Intelligence
IntelligenceBrian J. Piper, Ph.D.
Assessing Intelligence The Origins of Intelligence Testing Modern Tests of Mental Abilities Principles of Test ConstructionThe Dynamics of Intelligence Extremes of Intelligence
Assessing Intelligence Psychologists define intelligence testing as a method for assessing an individual’s mentalaptitudes and comparing them with others using numerical scores.
Alfred Binet Alfred Binet and his colleague ThéodoreSimon practiced a more modern form of intelligence testing by developing questions that would predict children’s future progress in the Paris school system. 1857-1911
Definition of Intelligence• "It seems to us that in intelligence there is a fundamental faculty, the alteration or the lack of which, is of the utmost importance for practical life. This faculty is judgment, otherwise called good sense, practical sense, initiative, the faculty of adapting ones self to circumstances. A person may be a moron or an imbecile if he is lacking in judgment; but with good judgment he can never be either. Indeed the rest of the intellectual faculties seem of little importance in comparison with judgment" (Binet & Simon, 1916, 1973, pp.42-43)
Alfred Binet Normal versus AbnormalEnvironmentalist 1857-1911
Lewis TermanIn the US, Lewis Terman adapted Binet’s test for American school children and named the test the Stanford-BinetTest. The following is the formula of Intelligence Quotient (IQ), introduced by William Stern: 1857-1936
Principles of Test ConstructionFor a psychological test to be acceptable it must fulfill the following three criteria: 1. Standardization 2. Reliability 3. Validity
StandardizationStandardizing a test involves administering the test to a representative sample of future test takers in order to establish a basis for meaningful comparison.Representative: Age, Ethnicity, Sex
Normal CurveStandardized tests establish a normal distribution of scores on a tested population in a bell-shaped pattern called the normal curve.
Flynn EffectIn the past 60 years, intelligence scores have risen steadily by an average of 27 points. This phenomenon is known as the Flynn effect.
ReliabilityA test is reliable when it yields consistent results. To establish reliability researchers establish different procedures: Split-half Reliability: Dividing the test into two equal halves and assessing how consistent the scores are. Test-Retest Reliability: Using the same test on two occasions to measure consistency.
ValidityValidity of a test refers to what the test is supposed to measure or predict. Content Validity: Refers to the extent a test measures a particular behavior or trait. Predictive Validity: Refers to the function of a test in predicting a particular behavior or trait. GRE & GPA
Extremes of Intelligence A valid intelligence test divides two groups ofpeople into two extremes: the mentally retarded (IQ70) and individuals with high intelligence (IQ 135). These two groups are significantly different.
High Intelligence Contrary to popular belief, people with high intelligence test scores tend to be healthy, welladjusted, and unusually successful academically.
Mental RetardationMentally retarded individuals required constant supervision a few decades ago, but with a supportive family environment and special education they can now care for themselves.