Biopsychology is the application of the principles of biology to the study of mental processes and behavior. A psychobiologist, for instance, may compare the imprinting 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. Biopsychology is another synonym for biological psychology.