In a departure from my usual posts, I can finally talk about my dissertation. Finally. I didn't like that in my last few posts I had to be so cryptic about what I was up to. That was partly due to the fact that some people who read my blog I needed as participants but mainly because I knew I wanted to devote a whole post to the project. I'm going to try to make a considered effort not to focus on how quickly the past six months have flown by and instead explain what I've been doing that has caused me to neglect this blog so terribly!

Everyone writes a thesis at the end of their degree but psychologists are asked to run our own experiment. Our thesis takes the form of a lab report on steroids. I was lucky enough to be given my first choice which fell under the realm of evolutionary psychology and linked two theories around human sense of smell.

Getting a little technical now, the major histocompatibility complex (MHC) is a genetic marker that helps with immune response. It comes in many different types and varies from person to person - this variation is advertised in body odour. If you're looking to have strong and healthy children, it makes sense to choose a mate who has different MHC genes than yourself, because your kids will be more likely to fight off a greater range of diseases. This is called disassortative mating. Unusually, the preference for a partner with opposite MHC genes is switched when a woman takes hormonal contraception like the pill.

There's another theory that states that the fragrances we like are related to the MHC. We like particular fragrances because they reflect and help advertise the MHC cues in our body odour to other people (i.e. potential mates). The idea behind my study was to find evidence for a link between these two theories.


I had couples in heterosexual relationships come to the lab (extremely high tech, as you can see) to fill out some questionnaires and then smell some smells! Participants completed some forms, a smell identification test, and then went on to smell some accords, which are ingredients that make up perfumes. Participants rated them out of 10 and ranked them in order of how much they'd like to wear them and how much they'd like their partner to wear them. I then compared their results with their partners and also looked at overall trends across gender and contraceptive choice.

7, 957 words, 72 references, 47 pages, and 155 days later, I submitted my findings!


As you might suspect, hardly anything was significant. I didn't find a strong correlation between couples preferring the opposite fragrances if they were using non-hormonal contraception, nor did I find a strong correlation between couples preferring the same fragrances if they were using hormonal contraception. Disappointing but not unexpected. It made for a lengthy discussion about why my findings don't support the current literature, which is always a good thing in science.

I did however find a significant difference in ratings for the vanilla-scented accord. Women not using hormonal contraception prefered the smell by far compared to both women on hormonal contraception and men. It's a completely novel finding and there's been very little research into vanilla so at least I've got that going for me! Not 100% sure what will be done with it or its significance for wider research but at least I discovered something new!

The main thing, however, is that my dissertation is over and done with! Contrary to popular belief, I did actually enjoy writing my dissertation and I can put that down to two things: the topic and lots of planning. Firstly, I have always had an interest in evolutionary psychology and contraception effects so the past semester and a bit were far more tolerable than if I had been researching into something like cognition. Secondly, I cannot stress the importance of organisation enough. You're far more likely to stay sane when you've planned to write your 8000 words leisurely over the course of a few weeks as opposed to everything in one caffeine-fueled weekend of pain and suffering. I owe a lot to the Bullet Journal system for keeping my life together too (even if it has continued to enable my obsession with stationery).

If you've made it to the end of this post, thank you! I know it's a total departure from my usual posts and I promise to get back to posting about my misadventuring soon! I'll wrap up this unreasonable wall of text with the same quote I used in my acknowledgements:

“A flower’s fragrance declares to all the world that it is fertile, available, and desirable. Its smell reminds us in vestigial ways of fertility, vigour, life force, all the optimism, expectancy, and passionate bloom of youth. We inhale its ardent aroma and, no matter what our ages, we feel young and nubile in a world aflame with desire.”

– Diane Ackerman, A Natural History of the Senses