Which researcher's studies provided evidence that the mind had a physical basis through nerve signaling?

The correct answer highlights Hermann von Helmholtz's significant contributions to the understanding of the relationship between mental processes and physical phenomena, particularly through his studies on nerve signaling. Helmholtz was influential in demonstrating that mental activity has a physical basis, specifically by measuring the speed of nerve impulses. His experiments revealed that sensory perception involves physical changes in the body, thereby providing a scientific basis linking the mind to the physical workings of the nervous system. This work laid the groundwork for later developments in psychology and neuroscience, emphasizing that our mental experiences are closely tied to physiological processes.

The other researchers listed, while notable in the field of psychology and neuroscience, primarily focused on different aspects of human thought and behavior. Wilhelm Wundt is known for establishing psychology as an experimental and scientific discipline, but he did not focus primarily on nerve signaling. Edward Kitchener contributed to structuralism and the study of consciousness but was not specifically involved in the research related to nerve impulses. Sigmund Freud emphasized the role of the unconscious mind and psychosexual development rather than the physiological underpinnings of mental activity.