COG - Psychometric Principles and Intelligence Testing Lesson

Learning Targets:

  • Explain how psychologists design tests, including standardization strategies and other techniques to establish reliability and validity.
  • Interpret the meaning of scores in terms of the normal curve. 
  • Describe relevant labels related to intelligence testing. 

AP psychology course and exam description, effective fall 2020. (n.d.). https://apcentral.collegeboard.org/media/pdf/ap-psychology-course-and-exam-description.pdf

How Do We Assess Intelligence?

Is there a way to measure intelligence? If so, how? Over the years intelligence tests have been developed to measure general mental abilities as well as attempts to measure overall aptitude. As intelligence tests have evolved, there have been several important qualities added to make them scientifically acceptable.

Achievement vs. Aptitude

Achievement tests are those that are designed to measure what you have learned - your knowledge or accomplishments in a certain area. The AP exam is an example of an achievement test. Aptitude tests on the other hand aim to measure or assess a person's potential or capacity to benefit from education or training.

What Makes a Good Intelligence Test?

IQ Bell Curve for the Population

Standardization

A good test needs to be standardized. This means that if the test is given to many subjects, it must first be piloted with a smaller but representative subgroup under the same conditions. Once scores have been received, norms or standards are established and create a normal distribution.

Reliability

Reliability refers to the ability of a good test to consistently produce similar scores on separate occasions. There are a couple of ways to achieve this including test-retest and split-halves methods.

Validity

Validity in a test means that the test has achieved measuring what it is supposed to measure.

Extremes in Intelligence

The normal bell curve for intelligence includes two extremes. The two groups that fall into these extremes differ noticeably.

The Low Extreme

  • The low extreme describes individuals whose test scores fall to 70 or below. A child with a low-test score and one that has difficulty adapting to the normal demands of life is labeled as having an intellectual disability. According to the DSM-5, which replaced the DSM-IV, the term mental retardation is no longer used to indicate that individuals are learning at a slower pace than the average person. The term intellectual disability or intellectual developmental disorder is used instead. Psychologists assess IQ and adaptive functioning to make a diagnosis and treatment recommendations. With the passage of Rosa's Law, the term intellectual disability is more commonly used in the United States.
  • In the DSM-5, communication disorders include language and speech disorders and social communication disorders. Learning deficits in the areas of reading, written expression, and mathematics are included in the category of specific learning disorders.

The High Extreme

  • The high extreme describes individuals with IQ scores of 135 or above. Children with this extraordinary academic gift are sometimes isolated and introverted. However, studies conducted by Lewis Terman found that most high-scoring children are healthy, well-adjusted, and academically successful.

Review

Review what you've learned in this module with the activity below.

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