The Guðjónsson Suggestibility Scale was created by Gísli Gudjonsson, a Professor Emeritus at King’s College London and an Honorary consultant Forensic Psychologist at Broadmoor.

The Guðjónsson Suggestibility Scale is protected and can only be viewed by forensic and clinical psychologists. It aims to test and discover the suggestibility of individuals.

The Guðjónsson Suggestibility Scale attempts to measure both:

Yield – Yield refers to an individuals susceptibility to suggestive questioning.

Shift – Shift refers to the suspect changing their answers as a result of the interrogation process and pressure.

The scale is measured via a test. The test consists of a narrative paragraph, which is read to the subject. Afterwards, the subject reports everything they can remember about the story. Later, the subject is questioned about the story, some of the questions lead them to false answers and some of them do not. After answering the questions a first time, the person being tested is told in a forceful manner that they have made a number of errors and must answer the questions for a second time. This leads to the person making even more errors than they made the first time. Read about Guðjónsson and Mackeith (1990) here.