The trance medium Leonora Piper was investigated by psychical researchers and psychologists in the late 19th and early 20th century. In an experiment to test if Piper's "spirit" controls were purely fictitious the psychologist G. Stanley Hall invented a niece called Bessie Beals and asked Piper's 'control' to get in touch with it. Bessie appeared, answered questions and accepted Hall as her uncle. The psychologist Joseph Jastrow wrote that Piper pretended to be controlled by spirits and fell into simple and logical traps from her comments. Science writer Martin Gardner concluded Piper was a cold reader that would "fish" for information from her séance sitters. The physiologist Ivor Lloyd Tuckett who examined Piper's mediumship in detail wrote it could be explained by "muscle-reading, fishing, guessing, hints obtained in the sitting, knowledge surreptitiously obtained, knowledge acquired in the interval between sittings and lastly, facts already within Mrs. Piper's knowledge."
Some scientists of the period who investigated spiritualism also became converts. They included chemist Robert Hare, physicist William Crookes (1832–1919) and evolutionary biologist Alfred Russel Wallace (1823–1913). Nobel laureate Pierre Curie took a very serious scientific interest in the work of medium Eusapia Palladino. Other prominent adherents included journalist and pacifist William T. Stead (1849–1912) and physician and author Arthur Conan Doyle (1859–1930).