First impressions of whether someone appears trustworthy are influenced by the faces we have just seen, according to new research from psychologists at the University of Aberdeen.
The study is the first to show that our snap judgements of trustworthiness are not based solely on the face in front of us. Instead, they are subtly shaped by the faces we have encountered only moments earlier.
The findings could have implications for situations where we rapidly view many faces, such as on dating apps and social media. The consequences could be even more important in settings where these judgements carry greater weight, such as eyewitness identification, where viewing one face may influence perception of trustworthiness of the next.
The study, carried out by researchers at the University of Aberdeen and Curtin University in Australia, investigated how recently seen faces influence first impressions of trustworthiness.
When interacting with strangers, we typically form an impression of how trustworthy they might be from a quick glance at their face. These impressions may then influence our relationships, social interactions, behaviour, emotions and many other aspects of daily life.
Some facial features tend to convey ‘high trustworthiness’ to others, and faces with these features have better career prospects and higher romantic attraction. These positive trustworthiness impressions are often driven by facial features that mimic positive emotional expressions, such as surprised-looking eyebrows or an upward mouth.
On the other hand, facial features judged to convey ‘low trustworthiness’ are linked with fewer career opportunities and fewer relationship prospects. Judgements of low trustworthiness are often driven by features that make a neutral expression appear angry, such as naturally highly arched eyebrows.
However, the researchers wanted to find out whether these first impressions are based purely on the characteristics of the face we are looking at or whether other faces that we have recently seen might subtly influence our impression of the current face. They studied whether our impressions of a face are distorted by the sequence of faces we see, to discover if social judgements can be unintentionally biased.
They found that recent visual experience can bias trustworthiness judgements in two opposite ways. The first way is that trustworthiness impressions of two faces became more similar than if we had seen each face in isolation, with the impression of the second face being ‘pulled toward’ the first face. This attractive bias happened when faces were viewed in quick succession, when they appeared in close proximity, or when they looked very similar.
The second way is that the trustworthiness impression of the second face was ‘pushed away’ from the first. This repulsive bias emerged when the viewing time of the previous face was extended, when the two faces were presented further apart in space, or when they had a very dissimilar appearance.
The study was funded by the UK Research and Innovation’s Economic and Social Research Council (ESRC) Serial Effects in Visual Perception: Towards an Operational Definition and a Unifying Model award. It was carried out by Dr Fiammetta Marini, Dr Clare Sutherland and Dr Mauro Manassi from the University of Aberdeen, and Dr Linda Jeffery from Curtin University.
Lead researcher Dr Fiammetta Marini said: “Judging trustworthiness is fundamental to daily life, influencing economic decisions, job interviews and even legal sentences. The goal of our study was to map the conditions that determine whether a previous visual experience will push us to ‘attract’ or ‘repel’ the judgement of trustworthiness of a new face towards or away from the previously seen face.
“This study is the first to systematically dissociate these effects, providing a basis for understanding how our social interactions are shaped by recent visual experience. We demonstrated that simple factors, such as how long we look at a face, where two successive faces are seen, or how similar they look, determine how the previous face will influence the trustworthy appearance of the following one.
“Traditionally, research has considered trustworthiness impressions as stable over time and solely dependent on the single face we are looking at. Here, we show that our impressions can be affected by what was seen in the past. Also, while studies on similar attractive or repulsive effects exist for simple visual characteristics (such as the orientation of a line), this is the first research to systematically demonstrate that the same principles govern complex social judgments such as perceived trustworthiness.”
Dr Mauro Manassi added: "We like to think we can instantly tell whether someone seems trustworthy, but our research suggests those first impressions are surprisingly easy to bias. Perhaps it's a reminder that first impressions are not always as objective as they feel, and that trust really does take time.”