Psychology and the Brain

Studying the Brain

Understanding the brain is of vital importance to psychologists because of its influence over behavior and mental states.

Learning Objectives

Trace the history of brain science in the field of psychology

Key Takeaways

Key Points

  • Psychology is the scientific study of behavior and mental processes.
  • Neuroscience shows that activity in the brain is intimately intertwined with behavior and mental processes.
  • Dualism is the disputed idea that the mind and the body are separate entities; it stands in opposition to the idea that consciousness can arise from purely physical processes.
  • Lesions and other brain abnormalities can be used to understand the functions of a healthy brain and their impact on behavior.

Key Terms

  • phrenology: A pseudoscience primarily focused on measurements of the human skull.
  • dualism: The idea that the mind and body are two separate entities which are made of separate substances but interact.
  • hard problem of consciousness: The question of how purely physical processes can give rise to the experience of consciousness.
  • lesion: Any abnormality in the tissue of an organism, usually caused by disease or trauma.

Psychology and the Brain

Psychology is commonly defined as the scientific study of behavior and mental processes. It has existed since the late 19th century, with 1879 often being given as a starting date because that was when the first psychological research lab was founded. Many schools of thought within the field have come and gone since then; some, like behaviorism, have persisted and evolved if they stood up to scientific study; others, like phrenology, have faded as they have lost credibility.

One approach has only begun to gain ground over the 20th and 21st centuries as scientific research and technology have improved: the study of the brain. Neuroscience is a relatively new field, but the more research that is done, the more it appears that much of human behavior and mental processes—the key interests for psychological study—are intimately intertwined with activity in the brain. Understanding the brain is important no matter what type of psychology you will be involved with, because its effects permeate all human behavior.

Research Using Lesions


Brain lesions: Though brain damage is deeply unfortunate, it can help researchers to understand more about the function of different parts of the brain. This image shows the location of a brain lesion on the left hemisphere which caused the patient to experience partial paralysis on their right bicep.

Studying damaged brains is one of the most useful ways to increase our understanding of the links between the brain and behavior. A lesion is a general term for any abnormality in tissue, usually caused by disease or trauma. Lesions are important to the study of brain and behavior because if a psychologist sees a person with a partially damaged brain and then sees changes in that person’s behavior, those behavioral changes can often be attributed to the brain damage. For example, damage to a part of the brain called Broca’s area causes patients to lose the ability to speak; knowing this, we can infer that that part of the brain is in some way related to language production. This gives us more information about neuroanatomy and also about the influence the brain has on behavior.


MRI of a brain lesion: Cancerous lesion (i.e., tumor) in the brain’s right cerebral hemisphere from lung cancer, shown on T1-weighted magnetic resonance imaging with intravenous contrast.

Mind-Body Dualism

Dualism is the idea that the mind and the body are two separate entities. Since the body is a physical entity and the mind is not, for many centuries philosophers (and later, psychologists) usually operated under the assumption that the body and the mind were of different kinds of substance. Rene Descartes famously theorized that the mind and body were separate, since he could doubt that he had a body because he might be dreaming, but he could not doubt that he had a mind since something was doing the doubting. Thus, the central claim of what is called Cartesian dualism is that the mind and the body are two separate substances that interact.

There is an ongoing debate today over whether the mind and body are separate materials, or whether consciousness can arise from purely physiological processes. This is known in psychology, cognitive science, philosophy, and artificial intelligence as the hard problem of consciousness.