The Biological level of analysis in psychology assumes that human behavior is strongly influenced by genetics and inherited characteristics.
The central nervous system and brain play a crucial role in determining thought and behavior, and understanding the structure and function of the brain is essential for explaining both. The building blocks of the nervous system are neurons, and chemical processes in the brain are responsible for psychological functioning.
Imbalances in these chemicals can lead to mental disorders such as bipolar mood disorder. Humans have evolved biologically through Darwinian evolution and share many characteristics with other animals, especially those closely related to us. Damage to certain parts of the brain can result in specific behaviors or behavioral changes.
Research on animals can also be used to inform our understanding of human behavior as humans and animals share similar biological structures.