Lasso of Truth period before, during and after World War I, on understanding and perfecting the systolic blood-pressure test while working on his Ph.D. in psychology at Harvard University. Blood pressure was one of several elements measured in the polygraph tests that were being perfected since as far back as Italian criminologist Cesare Lombroso, in 1895. Marston's wife, psychologist and lawyer Elizabeth Holloway Marston, one of his inspirations for the Wonder Woman character, also played a key role in his lie detector research. But the lie detector had nothing to do with Marston's creation of the Magic Lasso. Wonder Woman's "Magic Lasso" or
William Moulton Marston pressure test, which became one component of the modern polygraph invented by John Augustus Larson in Berkeley, California. Marston's wife, Elizabeth Holloway Marston, suggested a connection between emotion and blood pressure to William, observing that, "[w]hen she got mad or excited, her blood pressure seemed to climb". Although Elizabeth is not listed as Marston's collaborator in his early work, Lamb, Matte (1996), and others refer directly and indirectly to Elizabeth's own work on her husband's research. She also appears in a picture taken in his laboratory in the 1920s (reproduced by Marston, 1938). Marston set out to commercialize Larson's invention