In an ideal world, people wouldn’t judge each other on their image at all.

However, we don’t live in an ideal world; the small choices you make when dressing, the scar on your chin and the tattoo poking out from your collar are all data that our brains take into account almost immediately and – consciously or not – and use to formulate an opinion. This subconscious analysis is simply part of what makes us human.

Sigmund Freud postulated in his psychoanalytic theory in the early 1900s that the human brain is comprised of three levels of awareness or consciousness. Freud believed that our conscious mind takes up only ten per cent of our analytical bandwidth, whilst our subconscious comprises around 50-60% and our unconscious around 30-40%. Freud stated that your subconscious mind is the storage point for any ‘quick recall’ memories or associations. It also holds the information that you use every day, such as recurring thoughts, behaviour patterns, habits and feelings.

What does this mean for first impressions?

It means that essentially, all humans have immediate associations that are recalled as soon as we meet anyone new, and these biases help us formulate an image that contextualises the individual straight away. That tattoo on their wrist may recall the behaviours of past individuals with wrist tattoos, or that scar on their chin may elicit memories of dealing with others sporting scars.

What are the biggest factors people decide straight away?

One of the first things people decide after meeting you is whether they should trust you. This process, according to the Research Digest, takes just one-tenth of a second to conclude – in which time they’ve already decided if you’re trustworthy or not. Princeton researchers found this out by giving one group of 245 university students 100 milliseconds to rate the attractiveness, likeability, competence and trustworthiness of actors’ faces.

One hundred and twenty-eight members of another group were able to take as long as they wanted. Results showed that ratings of trustworthiness were highly similar between the two groups — even more similar than ratings of attractiveness — suggesting that we figure out almost instantaneously if we can trust someone.

The second thing people judge a new acquaintance on is their socioeconomic status; a Dutch study found that people wearing brand-name clothes were considered to have an immediately higher status than those wearing non-branded clothing. 

"Perceptions did not differ on any of the other dimensions that might affect the outcome of social interactions," commented the authors, as reported by Business Insider. "There were no differences in perceived attractiveness, kindness, and trustworthiness,” they added.

Other key defining factors include jewellery, the brand and materials of your watch, cologne or perfume, your haircut and our shoes.

A study conducted in 2007 by a Professor at Loyola Marymount University discovered that the first few seconds of an interaction also formulate an assumption on an individual’s intelligence. Similar aesthetic anchors that lead people to assume your socioeconomic standing also contribute to their view of your intelligence. Yet factors such as height, weight and age can also affect their assumption.

The study also found that confidence made a large impact on assumed intellect; Professor Nora A. Murphy from the university found that looking someone directly in the eye made a marked impact on their view of your intelligence.