We have all had that moment, on a date or just spending time with a romantic partner, when they do something that just makes our stomachs churn. It can be as small as them wearing a lime-green shirt or they held your hands in public, but whatever the cause it can put you off a person for good.

Lifestyle Editor Georgie recently argued that the “ickiest” students in Cambridge are STEM students with a mullet and especially those found vaping in the smoking area of Revs.

But where does this feeling come from? Is it a feeling we should trust, or is our revulsion completely unfounded?

The feeling can be a defence mechanism

One possible origin of the feeling could be as a way to protect yourself. Dr Elizabeth Cohen, a clinical psychologist, suggests that when children grow up not receiving attention or love they need from the adults in their life, they feel the need to justify to themselves that they don’t need these things. Children can then teach themselves to treat receiving those things as “icky”, which can follow them to adulthood. “As a kid, you can’t really feel what you’re missing, because you need to see your parents as safe and comfortable.”

When you start a relationship as an adult, the way your partner expresses their affection for you can often fulfil those needs that were unmet as a child. Having now built a barrier to those feelings however, these healthy expressions of love can feel like a threat and make you feel as if you need to shut them down.

They can save you from another bad relationship

Equally these feelings may stem from the need to protect yourself from another bad relationship. Not all icks come from people being nice to you, but disgust at your partner’s vaping habits or lack of pillow cases can be a trivial objection to save yourself from another potential bad relationship.

This is supported by the fact that these feelings tend to appear early in relationships during the “honeymoon phase”. As relationships begin you are much more sensitive to all the little flaws of a person as you decide whether you want to commit your time to them. As the relationship goes on, you become more accepting of your partner’s flaws and less likely to bolt for the door at the first sign of trouble.

You might be shaped by society’s expectations

Our expectations for our partners are shaped by our upbringing and the culture around us. As much as our desires are shaped by who we are, the expectations set by our peers play into much of who we date. When our partners unexpectedly fail to meet those expectations, the shock can cause our nausea for that person. Uncouth actions especially can put people off, compounding those feelings of disgust.

There might be no explanation

Human beings have a natural ability to invent explanations for why things are the way they are, even if they have no evidence as to why things are the case. A famous example can be seen in the work of neuropsychologist Robert Sperry into humans with split brains.

When the corpus callosum, the nerve fibres connecting the left and right half of the brain, is severed communication between each side is cut off. Each side of the brain controls opposite eyes and ears (right side of the brain controls the left eye and vice versa) but only the left side controls speech. Sperry discovered that when the right side was given an instruction such as: “Get up and walk around the room,” and the left side was asked to explain why they had done that, the person would invent an excuse such as: “I thought someone had knocked on the door,” and never say that the researcher had asked.

In much the same way our brains can react subconsciously to our partners in ways that make us uncomfortable or disgusted, but when asked why our brains can only invent excuses and never truly understand why.

There is still much that is unknown and still to research on why icks might occur. Whatever their cause might be, they can certainly be overcome in a lot of cases. So if your boyfriend suddenly decides he needs a mullet, or your girlfriend is awarded a Camfess top fan badge, know it might be worth powering through that feeling of disgust.