Biological psychology

In psychology, biological psychology, also known as biopsychology and psychobiology, is the application of the principles of biology to the study of mental processes and behavior. A psychobiologist, for instance, may compare the unfamiliarimprinting behavior in goslings to the early attachment behavior in human infants and construct theory around these two phenomena. Biological psychologists may often be interested in measuring some biological variable, e.g. an anatomical, physiological, or genetic variable, in an attempt to relate it quantitatively or qualitatively to a psychological or behavioral variable, and thus contribute to evidence based practice.
The study of biological psychology dates back to Avicenna (980-1037 A.D.), a Persian psychologist and physician who in The Canon of Medicine, recognized physiological psychology in the treatment of illnesses involving emotions, and developed a system for associating changes in the pulse rate with inner feelings, which is seen as an anticipation of the word association test. Avicenna also gave psychological explanations for certain somatic illnesses, and he always linked the physical and psychological illnesses together. He explained that humidity inside the head can contribute to mood disorders, and he recognized that this occurs when the amount of breath changes: happiness increases the breath, which leads to increased moisture inside the brain, but if this moisture goes beyond its limits, the brain would lose control over its rationality and lead to mental disorders.
Biological psychology as a scientific discipline later emerged from a variety of scientific and philosophical traditions in the 18th and 19th centuries. In philosophy, men like Rene Descartes proposed physical models to explain animal and human behavior. Descartes, for example, suggested that the pineal gland, a midline unpaired structure in the brain of many organisms, was the point of contact between mind and body. Descartes also elaborated on a theory in which the pneumatics of bodily fluids could explain reflexes and other motor behavior. This theory was inspired by moving statues in a garden in Paris.
Other philosophers also helped give birth to psychology. One of the earliest textbooks in the new field, The Principles of Psychology by William James (1890), argues that the scientific study of psychology should be grounded in an understanding of biology: