The ick can strike without warning. Prostock-studio/ShutterstockEver felt a sudden wave of cringe toward someone you were into – all because they wore questionable shoes or chewed a bit too loudly? Congratulations, you’ve caught “the ick”.That instant flip from attraction to total repulsion is everywhere on TikTok and Instagram, with singletons and couples bonding over the specific, often ridiculous triggers that turned them off. But beyond the viral memes and funny rants, why does our brain sometimes pull the handbrake so fast on an attraction?There are a number of potential explanations. Some psychologists have argued that the ick might be linked to the phenomenon of sexual disgust. Sexual disgust is hypothesised as an emotion that has been shaped by the selection pressure of evolution, which is the idea that women are hardwired to choose males that they can successfully mate with, to ensure the survival of their babies.From this perspective, while perhaps overzealous, the ick serves as a function to ensure appropriate mating. This theory comes with its limitations however, as not all women are dating or in relationships to reproduce. Additionally, this doesn’t necessarily explain why men also get the ick, and removes individual differences around the function of relationships for different people. It also doesn’t make sense for people in same-sex couplings.Dating today can feel like a mix of endless swipes, red flags and shifting expectations. From decoding mixed signals to balancing independence with intimacy, relationships in your 20s and 30s come with unique challenges. Love IRL is the latest series from Quarter Life that explores it all.These research-backed articles break down the complexities of modern love to help you build meaningful connections, no matter your relationship status.There have also been theories around the ick being linked to relationship anxiety. In relationship psychology, those with avoidant attachment styles avoid emotional closeness. So, when people with avoidant traits are dating or in a relationship, this may cause some anxiety for them. Arguably the ick may act as a defence mechanism to allow them to create distance from others and maintain their independence, which is their “safe space”. This suggests that avoidant people use the ick as a way of keeping themselves safe and maintaining a distance from others. Read more: Attachment theory: what people get wrong about pop psychology’s latest trend for explaining relationships We should also consider associations between past and current behaviours in potential partners. Some people may feel triggered by particular behaviours or mannerisms that remind them of past partners, meaning that they associate that behaviour with feeling icked out.Classical conditioning is pertinent to mention here. If we are conditioned to associate particular stimuli in the environment (such as witnessing someone consistently picking their nose and being told it is a disgusting habit), we are likely to become repulsed by this if we see the behaviour in others at a later date, and ultimately get the ick towards the person displaying that behaviour.An alternative explanation for the ick could be linked to certain phobias. For example, if someone has misophonia – sensitivity leading to decreased tolerance of certain sounds – this may mean things like loud chewing cause irritation. Ultimately, the answer to why people get the ick isn’t straightforward. All these proposed theories have their merits and limitations. But it appears to come down to individual differences.Rachael Leggett does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.