When most people think of topics to be studied as part of a PhD, chances are the music of pop star Justin Bieber isn't the first thing that comes to mind.
But for PhD candidate at the Australian National University Jessica Rahman, that's exactly what she's been studying, or more specifically, the effect his music, and other pop artists, have on people's brains.
For almost three years, Ms Rahman has been investigating why some people respond positively to some types of music and negatively to others.
And it was all because of a Bieber hit that started her down the path.
"I heard the song of his Love Yourself and it was a relaxing piece, and thought I really liked the music, but I was always a Justin Bieber hater beforehand," she said.
"I was surprised by the effect, and I had a bias before against that type of music but when I listened to it, I had a different reaction."
Ms Rahman's research has delved into how music effects people on a physiological level, such as brain activity, heart rate and skin conductance.
Her field of research may be a bit more left-of-field compared to a standard thesis, but Ms Rahman said the body of work will help to solve real-world issues in determining the physiological effect music has on our bodies.
"There's definitely been a good response to it, and people have generally been very excited about it," she said.
"It's working on a problem that's relevant to the general population because we all listen to music and we don't know the impact that it's having on us.
"You could be walking to the grocery store and don't know why you're annoyed and it could be due to the background noise."
While Ms Rahman is set to become a doctor following the completion of the PhD this year, she said she wasn't phased about the recent public debate about academics using the title of doctor.
The debate came following a controversial Wall Street Journal opinion piece which said incoming First Lady Jill Biden should drop her title of doctor, attained doing a doctorate in education, because she's not a medical doctor.
After years of academic study, Ms Rahman said the title of doctor after attaining a PhD was an achievement in of itself.
"It's a title I held in very high regards, and I definitely don't see why you would want to drop a title like that for any reason," she said.
"It's an honourable title."
It's a similar feeling experienced by recent PhD graduate at the Australian National University Dr Katie Cox, who examined the influence of US national security through the lens of Iron Man.
"PhDs are poorly understood by a lot of people and it's hard to understand unless you haven't done it yourself or been close to someone who has," Dr Cox said.
"My parents are both medical doctors, so when I graduated and became a doctor they were over the moon.
"The title of doctor originally came from academia, and when I graduated mum said 'we finally have a real doctor in the family'."
While many PhDs have examined national security policies, Dr Cox said looking at it through the lens of Marvel's Iron Man gave it unique perspectives.
"I wanted to look at at why, especially in America, national security was so compelling and I looked at stories of heroism in America and how they were presented in pop culture," she said.
"When the first Iron Man movie came out in 2008, it was towards the end of the Bush era and the War on Terror was dragging out with no clear end in sight.
"Iron Man then bursts onto the scene and, unusually for a superhero movie, directly engaged in Afghanistan and issues of terrorism and American intervention."
She said the Iron Man was the latest iteration of superheroes, be they in movies or in comics, directly engaging with American wars and actions overseas.
"What I studied was really about how those narratives and how those heroic interventions and saving the day through technical innovation influenced people's perceptions of national security," she said.
Having worked on the PhD thesis for several years, Dr Cox said the response she had from people when telling them about her area of studying was surprising.
"Most people were positive about it and they were astonished that you were able to study things like that," she said.
"There was some skepticism about it, but for the most part, people were excited and interested about it."
Dr Cox said becoming a doctor was just one of many rewards of completing a PhD.
And while some circles have criticised academics becoming a doctorate, it's not a title Dr Cox is giving up any time soon.
"It's not about contests about who is and isn't a real doctor, everyone is trying to contribute something helpful and useful to the world," she said.