Hermann Munk made important contributions to the field of psychology regarding the route from the eye to the brain through his meticulous research methods. In 1878, he published findings from studies involving dogs and monkeys that led to the conclusion that vision was localized in the occipital cortical area. Amid scrutiny, he repeated his study and published similar findings in 1881. His focus was on dogs and he, unlike many others of his time, kept his subjects alive for an average of 5 years in order to study long term effects.
Throughout his research he discovered that cortical lesions in the visual areas lead to blindness. He called blindness experienced after the posterior portion of the occipital cortex was damaged Seelenblindheit, or psychic blindness. While suffering from psychic blindness, dogs were able to navigate effectively but showed no sign that they recognized what the objects in front of them were when they were only allowed to use sight. The dogs normally recovered from psychic blindness in 4 to 6 weeks and did appear to relearn faster than they first learned object meanings. The second type of blindness, Rindenblindheit, or cortical blindness, results from much larger lesions in the occipital cortex. Cortical blindness appears as a complete loss of vision and shows that vision involves areas surrounding the occipital cortex.