Cognitive neuropsychology is a branch of cognitive psychology that aims to understand how the structure and function of the brain relates to specific psychological processes. Cognitive psychology is the science that looks at how mental processes are responsible for the cognitive abilities to store and produce new memories, produce language, recognize people and objects, as well as our ability to reason and problem solve. Cognitive neuropsychology places a particular emphasis on studying the cognitive effects of brain injury or neurological illness with a view to inferring models of normal cognitive functioning. Cognitive neuropsychological methods include brain pathology, recording, stimulation, brain imaging and the study of developmental deficits. Evidence is based on case studies of individual brain damaged patients who show deficits in brain areas and from patients who exhibit double dissociations. Double dissociations involve two patients and two tasks. One patient is impaired at one task but normal on the other, while the other patient is normal on the first task and impaired on the other. For example, patient A would be poor at reading printed words while still being normal at understanding spoken words, while the patient B would be normal at understanding written words and be poor at understanding spoken words. Scientists can interpret this information to explain how there is a single cognitive module for word comprehension. From studies like these, researchers infer that different areas of the brain are highly specialised. Cognitive neuropsychology can be distinguished from cognitive neuroscience, which is also interested in brain-damaged patients, but is particularly focused on uncovering the neural mechanisms underlying cognitive processes.
