Biological Psychology is the study of the physiological, evolutionary and developmental mechanisms of behavior and experience. The term biological psychology emphasizes that the goal is to relate biology to issues of psychology. It is more than a field of study; it is also a point of view. It holds that we think and act as we do because of certain brain mechanisms, which we evolved because ancient animals with these mechanisms survived and reproduced better than animals with other mechanisms.

It is a sister idea of Darwinism, the full concept of evolution and survival of the fittest amongst species. The human species is one that have prevailed the most, we can live in extreme cold temperatures as well as extremely hot temperatures, we have adapted and survived. Applying the theory of survival of the fittest every single day of our existence. 

Much of biological psychology concerns brain functioning. Brain functioning could give some biological explanations of behavior. To explain why humans don’t always know the reasons for their actions, there are some biological explanations that could resolve this issue and they fall into four categories.

First we have the physiological explanation; that relates a behavior to the activity of the brain and other organs. Then there is the ontogenetic explanation that describes how a structure or behavior develops, including the influences of genes, nutrition, experiences, and their interactions. Third it is an evolutionary explanation that reconstructs the evolutionary history of a structure or behavior. Finally we have the functional explanation that describes why a structure or behavior evolved as it did.

What biological psychology is trying to do is explain why and how the brain became conscious, in order to answer the mind – body problem.