If you’re planning to celebrate Valentine’s Day with a new partner, there’s a good chance that you met online, which surveys suggest is fast becoming the most popular way people get together. Of course, searching through profile after profile brings with it a variety of difficulties.
Perhaps surprisingly, research shows that one of those problems is simply trying to avoid being influenced by the order in which you view those profiles.
“Sequential effects” (or “serial dependence”) is a type of bias known in the field of psychology. Researchers have found that the previous item in a sequence affects how you judge the current item, whether this involves grading Olympic performances or students’ essays.
We also know that people’s judgements of facial attractiveness show this bias. The direction of the effect can go in one of two ways – the attractiveness of the current face is either pulled towards our opinion of the previous one (assimilation) or pushed away from it (contrast).
This may depend on how similar we think the two faces are in other aspects like gender or ethnicity. High similarity between faces tends to lead to more assimilation. Low similarity produces less assimilation, or may even lead to contrast.
For instance, if the last photo you saw was very attractive and the one you’re currently considering shares several features in common (for example, both are south Asian women with long, dark hair) then you’re more likely to rate this one as attractive too.
These biases also apply to other trait judgements like trustworthiness, intelligence and dominance. So in the same way that our opinions about attractiveness are influenced by the previous face we saw, judgements about numerous other qualities are too.
To complicate matters, it isn’t clear whether these sequential effects are caused by a perceptual bias (what we thought of the previous face might change how we see the current one) or a response bias (how we physically responded to the previous face might affect our next response) since researchers typically ask participants to rate every face during the study.
But one UK study from 2021 tried to separate out these explanations by asking participants to view (but not respond to) the previous face before rating the current one. The results showed a contrast effect, where judgements of the current face shifted away from the attractiveness of the face seen before it (given by a different set of participants). Therefore, the direction of bias might depend on whether we’re simply viewing faces or having to actively judge them.
Of course, attractiveness judgements often take the form of a binary decision (“hot or not”) when viewing dating profiles, much like the left or right swipe used by platforms such as Tinder. Researchers have also found sequential effects with this type of judgement.
Participants in a 2016 study viewed a sequence of faces and decided whether each was “attractive” or “unattractive”. The results demonstrated an assimilation effect – participants were more likely to rate a face as attractive when they thought the preceding face was attractive than when it was unattractive.
While research has shown that photos play the biggest role in a dating profile’s overall attractiveness, other factors such as language errors in the text can influence our judgements. Interestingly, in one study where pictures and text from the same dating profile were rated by different people, there was a correlation between the rated attractiveness given to the photos and the (separately rated) text that accompanied them.
Since ratings of perceived confidence were also collected, the researchers were able to show that physically attractive people tended to write accompanying text which came across as more confident, with this text judged to be more attractive by others.
So what can we take away from all these studies? You may already know about plenty of biases that people show when perceiving the world. For instance, people are susceptible to spotting faces in inanimate objects or more likely to attribute positive qualities to attractive people.
However, you may not have been aware that viewing sequences of things can change your judgements. That’s not to say that choosing your current partner was entirely due to the quality of the profile that happened to pop up before theirs, but it may well have played a role.
Robin Kramer 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.