---
born: 1896-01-12
category: Scientists & Researchers
created: 2026-06-03
died: 1981-05-02
location: New York, New York
summary: Psychologist who developed the Wechsler Adult Intelligence Scale and related
  tests, which formed the foundation of John Gittinger's CIA Personality Assessment
  System for evaluating and predicting behavior.
tags:
- Person
- CIA
- MKULTRA
- PersonalityAssessmentSystem
- Psychology
updated: 2026-06-03
---

David Wechsler was a psychologist who developed the Wechsler intelligence scales, a standard IQ test with 11 parts that became the foundation of the [CIA](/organizations/central-intelligence-agency/)'s [Personality Assessment System](/concepts/personality-assessment-system/). [John Gittinger](/people/john-gittinger/) used Wechsler's battery of subtests, including digit span, arithmetic, block design, and picture arrangement, as the raw data for classifying personalities into types such as Internalizer versus Externalizer and Regulated versus Flexible. Different versions of the test were called the Wechsler-Bellevue and the Wechsler Adult Intelligence Scale. Gittinger made modifications that he incorporated into what he named the Wechsler-Bellevue-G.[^1]

The Wechsler system proved remarkably fertile for intelligence purposes. With 10 subtests and at least 10 possible scores on each, no two results in Gittinger's data base of 29,000 sets ever looked exactly the same. The tests could be administered under cover as "aptitude" tests to newly recruited agents. Gittinger's staff developed localized versions for various nations, understanding that the Wechsler battery had cultural bias and that a Japanese Externalizer had a very different personality from a Russian one.[^1]

[^1]: John D. Marks, *The Search for the Manchurian Candidate*, Chapter 10.