Early Research
The first seeds of forensic psychology were planted in 1879, when Wilhelm Wundt, often called the father of psychology, founded his first lab in Germany. Since Wundt, the field of forensic psychology has blossomed, with contributions by lots of other experts. James McKeen Cattell, for example, conducted some of the earliest research on the psychology of testimony. He posed a series of questions to students at Columbia University, asking them to provide a response and rate their degree of confidence in their answer. He found a surprising degree of inaccuracy, inspiring other psychologists to conduct their own experiments in eyewitness testimony. With even eyewitnesses being unsure of themselves, this raised serious issues about the validity of their usefulness in court. Inspired by Cattell’s work, Alfred Binet replicated Cattell’s research and studied the results of other psychology experiments that applied to law and criminal justice. His work in intelligence testing was also important to the development of forensic psychology, as many future assessment tools were based on his work. Psychologist William Stern also studied witnesses’ ability to recall information. In one of his experiments, he asked students to summarize a dispute they witnessed between two classmates. Stern discovered errors were common among witnesses and concluded that a person’s emotions could affect how accurately he remembered things. Stern continued to study issues related to court testimony and later established the first academic journal devoted to applied psychology.
Forensic Psychology in the Courts
During this time, psychologists were beginning to act as expert witnesses in criminal trials throughout Europe. In 1896, a psychologist by the name of Albert von Schrenck-Notzing testified at a murder trial about the effects of suggestibility on witness testimony. The German-American psychologist Hugo Munsterberg’s belief that psychology had practical applications in everyday life also contributed to the development of forensic psychology. In 1915, Munsterberg published “On the Witness Stand,” a book advocating the use of psychology in legal matters. Stanford psychologist Lewis Terman began applying psychology to law enforcement in 1916. After revising Binet’s intelligence test, the new Stanford-Binet test was used to assess the intelligence of job candidates for law enforcement positions. In 1917, psychologist William Marston found that systolic blood pressure had a strong correlation to lying. This discovery would later lead to the design of the modern polygraph detector. Marston testified in 1923 in the case of Frye v. the United States. This case is significant because it established the precedent for the use of expert witnesses in courts. The Federal Court of Appeals determined that a procedure, technique, or assessment must be generally accepted within its field in order to be used as evidence.
Forensic Psychology Gains Traction
Significant growth in American forensic psychology did not happen until after World War II. Prior to that time, psychologists served as expert witnesses, but only in trials that weren’t perceived as infringing on medical specialists, who were seen as more credible witnesses. In the 1940 case of People v. Hawthorne, the courts ruled that the standard for expert witnesses depended on how much the witness knew about a subject, not whether the person had a medical degree. In the landmark 1954 case of Brown v. Board of Education, several psychologists testified for the plaintiffs and the defendants. Later, the courts gave support to psychologists serving as mental illness experts in the case of Jenkins v. the United States. Forensic psychology has continued to grow and evolve during the past three decades. Increasing numbers of graduate programs offer dual degrees in psychology and law, while others offer specialized degrees emphasizing forensic psychology.
