AP Psychology
Unit 13: Intelligence & Testing
13.2 Evolution of Testing

Notes Outline

  • Galton & Eugenics
  • Binet & Mental Age
  • Terman, Stern, & the IQ
  • Wechsler & the WAIS

Galton & Eugenics

  Cousin of Darwin, raised in an affluent British family – based on his experience and the people he knew (all also affluent, white, British men) he concluded that intelligence must be inherited.

He tried to create an intelligence test in order to empirically prove his assertion, focusing on sensory perception. 

He was…super bad at it. Super bad. Never managed to create an intelligence test. But along the way he concluded that sensory perception does not connect to intelligence, coined the phrase nature v. nurture, correlation, and percentile. Also set the stage for Binet…

Alfred Binet & Mental Age

In early 1900’s Binet was asked to create an objective test to identify children with mental disabilities.

Worked with Theodore Simon and created the Binet-Simon scale that measured a variety of abstract reasoning skills. The results were termed in a participants MENTAL AGE – a measurement that indicated the participant had the mental abilities of an average person of that age.

Terman & Stern

Built on the work of Binet-Simon.

Stern introduced the idea of an INTELLIGENCE QUOTIENT (IQ) that was a child’s mental age divided by chronological age times 100.

Terman pushed the idea of IQ testing children in order to place children educationally – New version called the STANFORD-BINET IQ test (created at Stanford University)– gold standard for intelligence testing

Wechsler & the WAIS

Found the Stanford-Binet to be lacking with adult patients – created the Wechsler Adult Intelligence Scale (WAIS)

Wechsler scale less dependent on verbal ability of participant – used items that required non-verbal reasoning

Also got rid of IQ in favor of a NORMAL DISTRIBUTION --> Became so popular even the Stanford-Binet adopted a normal distribution instead of a quotient. So IQ is a weird anachronism...

Normal Distribution is a symmetric, bell-shaped curve that represents the pattern in which may characteristics are dispersed in a population. In a normal distribution of a trait most cases fall in the middle