As Alex Hitchens in 'Hitch', Will Smith told us that "clothes make the man". Well-dressed though he is, Will Smith did not come up with this idea on his own. These words are first thought to have been spoken by the Renaissance humanist Erasmus around 400 years ago. However, a good idea is a good idea for all time, and this quote remains a probing summary of the psychological impact our clothes have not only on our productivity, but also on other people's perception of us and the perception we have of ourselves. Erasmus was right, clothes really do make the man, and for that matter, the woman.

Dress to impress

The idea that our clothes have a fundamental impact on the way we are perceived in the world is not a new one – there is a multi-billion pound fashion industry in the UK alone that does very well out of it. We know we have to 'dress the part' when we get suited and booted for work in the morning and we often want to 'dress to impress' when we put our glad rags on to see our friends at the weekend. However, recent studies suggest that subtle differences in clothing and appearance can have a more significant effect on career success than one might have previously imagined. This is surprising, given that in an ostensibly more meritocratic world most people believe they should judge and be judged on their capability rather than their wardrobe.

A 2013 study suggests that even those with the best intentions of judging by merit actually have very little choice in the matter, as we subconsciously make assumptions about others based on their appearance before we have even seen their face or heard them speak.

This experiment involved a group of observers seeing two images of a male with his facial features pixelated in two different poses and wearing two different suits. One suit was a bespoke tailored suit and the other an off-the-rail suit (although they were otherwise similar in material and colour). Despite only seeing the images for 5 seconds, the observers rated the man in the tailored suit more positively in terms of confidence, success, trustworthiness, salary and flexibility. Lucky him.

Not everyone has the means to wear a tailored suit every day (or would want to!), but the results of this study are arresting. Even those of us with no trained eye or appreciation for the cuts of Savile Row on some level notice the difference between a smart and a super-smart suit. More than that, we make judgements about the person wearing that suit (or not) maybe without even realising.

Dress the part

Enough about other people. We all know how it feels to put on that killer LBD that miraculously helps us shed two dress sizes, or that perfect jacket that stops us feeling quite so nervous when we go for a job interview. Everyone has a couple of items in their wardrobe that they go to when they need to give themselves a lift, and it's natural that our clothes impact on the way we feel about ourselves.

In a study carried out at Northwestern University subjects were given a lab coat to wear which they were told was a doctor's coat. Whilst wearing the coat subjects displayed higher levels of concentration compared to not wearing a lab coat. Interestingly, when the same coat was described as a painter's jacket subjects showed lower levels of concentration than they did when the jacket was described as a doctor's coat. The authors of this research argue that this demonstrates that our performance in various tasks is affected by both the symbolic meaning we attach to our clothes and the physical experience of wearing them. Similarly, in a 2011 study, subjects on a golf course who believed they were using a putter that previously belonged to a pro performed better than their non-believing counterparts.

We have no choice but to start thinking about the relationship between our clothes and our roles from an early age – usually around the age of 5 when we start wearing school uniform. School uniform trains us to associate certain items of clothing with certain behaviours, so it's no wonder this association stays with us in our adulthood as well.

Research into the psychological effects of school uniforms is extensive; however, it also appears to be inconclusive. Some studies suggest that a school uniform is beneficial in that it unites a school community, teaches children about professionalism, improves behaviour and eliminates the pressure on parents to keep their children in fashionable clothes. However, opposing studies suggest that a uniform is detrimental in that it stifles a child's creativity and personality, is an expense to families in itself and encourages rivalry between institutions. It's also seldom the most flattering outfit – either in colour or shape – that a person wears!

Smart vs. Casual

So, should workplaces enforce their own 'school uniform' of formal dress codes to enhance productivity? The answer would appear to be no. The value of a formal dress code will be completely dependent on the culture a business wants to achieve and the type of work it undertakes. A study published in Business Communication Quarterly in 2009 suggests that casual dress is generally associated with creativity and friendliness whilst more formal attire is associated with authoritativeness and competence.

Indeed, for many businesses, a one size fits all approach will be inappropriate given the fact that most organisations are made up of people with a variety of skills carrying out a variety of different roles.

Perhaps the way forward is to allow employees the autonomy to decide what they wear based on what they want to achieve in their working day. This approach is taken by companies such as Google, who encourage employees to wear what makes them comfortable, and the consultancy firm Oliver Wyman, where employees are not required to wear formal clothes when they are not doing client-facing work. These kinds of policies will be particularly effective for companies that are confident in their recruitment process (discussed by an RPC trainee here): if you believe you have the team that you want for your business, why would you worry about what they wear?

For those businesses and industries in which it is accepted that formal wear is the most appropriate and productive dress code, the odd 'home clothes day' or dress-down Friday can also be a cheap but effective means of incentivising or rewarding employees. There is no cost to a business in letting people wear their own clothes, but that gift of autonomy and trust – however short-lived – can provide a real boost to morale.

If one thing is clear, it is that this has nothing to do with fashion. This is about what our clothes symbolise in the context of where we work and what we want to achieve. The bad news is that we cannot stop ourselves from making the link between clothes and an impression of status or competency, as the lab-coat and tailored suit surveys conclusively show. The good news is that according to Fashion Psychologist Karen Pine, in the event of some symbolic fashion faux pas we can 'compensate and correct' the impression we have made by adjusting our behavior accordingly. Well, you'd certainly hope so!