What do the different initials after a scientist’s name mean?

In this blog post, we take a detour from our discussion of memory to answer this question posed by one of our readers. This reader noticed that in articles about scientific discoveries, the people quoted often have initials after their names, such as “Ph.D.” or “M.D.” or “M.A.”. This reader asked what all those initials mean.

These initials all relate to the type of education that the person has received. Usually, people include these initials if they have continued to go to school for additional years beyond college. The specific initials tell you what type of degree (additional education) they received.

There are a few things that are confusing about these initials.

First, when initials include a “D,” that stands for “Doctor.” But it’s not always the type of doctor that you may think of (like your pediatrician):

Ph.D. stands for Doctor of Philosophy. While this label might make you think the person specifically studied the field of philosophy, actually, a person can receive a Ph.D. in a large number of fields — Neuroscience, Biology, Chemistry, English, Psychology, Economics, etc — and the degree is always referred to as a Ph.D. Those who have earned a Ph.D. have spent additional years beyond college studying their specific field, and have contributed something new to that field. For instance, someone with a Ph.D. in neuroscience has discovered something new about the brain that was not known prior to their own research.

M.D. stands for Doctor of Medicine. D.O. is another type of medical degree, a Doctor of Osteopathic Medicine. Those who have earned an M.D. or d.O. have spent additional years beyond college studying the scientific fields that are relevant to the practice of medicine. Many with these degrees focus primarily on patient care (for instance, your pediatrician may have an M.D. or D.O.). But some with an M.D. or D.O. degree also spend time on the practice of science (working toward discoveries that may one day improve patient care).

There are many other types of degrees that people can receive as well. As just a few examples: J.D. represents a law degree; Ed.D. represents a degree in education; Psy.D. represents training specific to psychological therapy.