Check out the ongoing twitter hashtag about why people did, or are doing, a PhD. Some examples below. It appears that the hashtag was started by Miriam Goldstein, a marine biologist & science communicator working in policy (@MiriamGoldste)(http://www.miriamgoldstein.info).

Tweet @CauseScience1 and @MiriamGoldste to tell us why you did a PhD, or why you are doing a PhD.

#whyididaphd: Because I wanted to do cool stuff while wearing jeans, & be the first Dr. in my family. (Not the most concrete career goals!)

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Miriam Goldstein (@MiriamGoldste) September 30, 2014

I'm curious. About everything. Especially neurons. #whyididaphd #whyimDOINGaPHD (in progress)

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SPOO-HOO-HOOKY Owl (@leon_summer) October 02, 2014

i like science. #whyididaphd

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Michael Hendricks (@MHendr1cks) October 02, 2014

I believe that knowing more about the brain and how mental illnesses develop will lead to better diagnosis and treatments. #whyididaphd

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Katie (@katiesci) October 02, 2014

Because I am passionate about science and cannot imagine myself doing other than that #whyididaphd

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Doctor PMS (@Doctor_PMS) October 02, 2014

Because I wanted to change the world, somehow make it better. So far, it hasn't worked. But I remain egotisically optimistic. #whyididaphd

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Sci Curious (@scicurious) October 01, 2014

#whyididaphd - Because I am a huge nerd that thinks that neurons and the brain are cooler than just about anything else. Also, #CauseScience

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CauseScience Blog (@CauseScience1) October 02, 2014