The science museum in London has interesting items on display in the Psychology: Mind Your Head exhibit. Unfortunately, not all of them are on the website so here are some I photographed.
A skull showing phrenology markings with a device used to measure the features of a head for phrenological interpretation. Phrenology was a radical idea developed by Franz Joseph Gall in the 19th century. He said that different mental faculties like memory, sensation and instincts can be interpreted from the different features of a person's skull. It was against the religious thought at that time as the Catholic church refused the idea that the mind and it's faculties can be localized to physical structure i.e. the brain. Phrenology became very popular in Britain in the mid 19th century and it was used to compare the superiority of colonialists compared to the 'savages'. Now it's a pseudoscience.
Another phrenology related instrument.
The first world war introduced to psychology the idea that extreme stress could cause mental disorders. This was called war neurosis or shell shock. But before this realization it was considered cowardice and some soldiers in Britain were executed. Some of those who weren't executed were given an electrical shock in the back of the pharynx in an attempt to treat their hysterical behavior. Pictured above a Faradic battery that was used to apply the shock. Now the modern concept of shell shock is known as posttraumatic stress disorder.