2 Intelligence Assessing Intelligence The Origins of Intelligence Testing Modern Tests of Mental Abilities Principles of Test Construction The Dynamics of Intelligence Stability or Change? Extremes of Intelligence
3 Assessing Intelligence Intelligence testing is a method for assessing an mental skills and comparing them with others using numerical scores.
4 Alfred Binet (1905) and Simon started modern intelligence testing in the Paris school system.
5 Lewis Terman adapted Binet’s test and named the test the Stanford-Binet Test. The formula of Intelligence Quotient (IQ) introduced by William Stern is:
6 Aptitude and Achievement Tests Aptitude tests are intended to predict your ability to learn a new skill and achievement tests are intended to reflect what you have already learned.
The Wechsler Scales Age-related versions provide an overall IQ and also yield both verbal and performance IQs. (WPPSI-III) Wechsler Preschool and Primary Scale of Intelligence-Revised. Ages 2 ½ to 7 years, 3 months (WISC-IV) Wechsler Intelligence Scale for Children-Revised. Ages 6 to 16 years, 11 months (WAIS-III) Wechsler Adult Intelligence Scale-Revised Ages 16-89
9 Principles of Test Construction For a psychological test to be acceptable it must fulfill three criteria: 1.Standardization 2.Reliability 3.Validity
10 Standardization Standardizing a test involves administering the test to a representative sample of future test takers in order to establish a basis for meaningful comparison.
11 Normal Curve Standardized tests establish a normal distribution of scores on a tested population — a bell-shaped pattern called the normal curve.
12 Flynn Effect In the past 60 years intelligence scores have steadily risen by an average of 27 points — a phenomenon known as the Flynn effect.
13 Reliability A test is reliable when it yields consistent results. To establish reliability researchers establish different procedures: 1.Split-half Reliability: Dividing the test into two equal halves and assessing how consistent the scores are. 2.Reliability using different tests: Using different forms of the test to measure consistency between them. 3.Test-Retest Reliability: Using the same test on two occasions to measure consistency.
14 Validity Reliability of a test does not insure validity. Validity of a test refers to what the test is supposed to measure or predict. 1.Content Validity: Refers to the extent a test measures a particular behavior or trait. 2.Predictive Validity: Refers to the function of a test in predicting a particular behavior or trait.
15 Stability or Change? Intelligence scores become stable after about seven years of age.
16 Extremes of Intelligence The mentally retarded (IQ = 135) are significantly different.