On a United Airlines flight from Newark to Denver in August, a small piece of plastic caused an unexpected diversion to another airport – and headlines around the world. It started when one passenger had used a “Knee Defender” – a $21.95 piece of plastic that attaches to the tray table and blocks the seat in front in an upright position. A furious row ensued, with name-calling and drinks being thrown – and the plane had to make an emergency stop in Chicago, with police escorting both passengers off the flight.

The use of the Knee Defender is an extreme example of some of the tricks we use to try and make our commute – by bus, train or plane – that little bit more comfortable. The fight for space on public transport can turn the meekest among us into a rebel. But while we might be aware of the tricks we pull to afford ourselves that extra bit of space, we’re not necessarily aware of those being played on us by transport operators – the “nudge”.

Persuading people to do the right thing when they’re travelling is a nuanced business. The nudge is the unspoken ushering towards a way of acting that makes life easier for everyone, be it on a cramped Tube train or a commuter flight. So how do they trick us into behaving the way they want – ideally without us even noticing they are doing it?

Armrest update

Let’s take the popular sport of elbow fights over armrests in aeroplanes. Sometimes it can be a simple design nudge that keeps the peace. Paperclip Design, a Hong Kong-based company, has developed a prototype of an armrest that has two levels; while one passenger’s elbow rests on top, the other’s fits at the lower level of the armrest, says inventor James Lee, the company’s director.

It’s still a concept, but small-scale trials suggest that it makes for happier passengers, he says. “It can reduce significant frustration regarding the space for elbows,” says Lee. Now the firm is “in discussions with some interested parties”.

Creating a better environment for users is vital, says Lee. “Not just something pleasant looking, but also practical, useful and ergonomic. All these factors naturally influence passengers’ behaviour.”

Nudging to make us better passengers is also happening even before we board the planes – at airports. Behavioural scientist Pelle Guldborg Hansen, founder of the Danish Nudging Network is looking for environmental “nudges” to change people’s behaviour. He hopes to persuade passengers to board planes as orderly and efficiently as possible, without bossing them around. Hansen’s concept revolves around the idea of helping passengers make better choices.

To improve the boarding process at Copenhagen airport, Hansen and his team have tracked the behaviour of passengers near the departure gates of more than 500 flights. All that was needed to make the departure area less chaotic, says Hansen, was to nudge people to sit down, because a seated passenger is less of an obstacle than a standing one.

“In open gate areas, people tend to distribute evenly in the seating area. However, in some cases this is not optimal since this seating pattern has some people sitting near the main walking areas, making it difficult for passengers arriving late to get to a seat. These newcomers just see a difficult path, with obstacles such as feet, legs and luggage, says Hansen.

Steering passengers

His team realised that even when the gate area was full of people, only 70-90% of seats were taken. A subtle redesign was needed. One quick way to nudge passengers to sit down, for example, is to position power outlets in areas furthest away from the airport’s “main street”. Families can also be nudged to sit in corners with more seating, which leaves “corridors” free of luggage and pushchairs. Another trick is the strategic location of visual displays with information. “Our observations have shown the proximity principle to be at work – people place themselves systematically near informational screens,” says Hansen.

Then there is the trick to put more attractive chairs in areas where you want to steer people to – all with the purpose of influencing seating patterns in ways that would make it “perceptually easier” for travellers to use all space and make it easy to get to a free seat.

The researchers noticed another reason why the seating capacity at gates was not used to the max: the distribution and placement of chairs simply does not meet people’s preferences. “Think of table-sizes of restaurants,” says Hansen. “People prefer their own table, so to run an effective operation, restaurants change table sizes constantly.”

At airports that isn’t an option – so to optimise seating capacity, airports have to consider the preferences of different types of travellers. “Single travellers tend to sit in the corners, and couples next to each other, for instance,” says Hansen.

Nudging with signs

Passengers, of course, don’t always play along, and create extra private space by placing luggage on a seat next to them. “We observed how chair design could nudge people not to do this, and found that the mere introduction of an armrest here and there reduced luggage on seats, making it possible for more people to sit down,” says Hansen.

Hansen is now briefing airport architects and interior designers on how to redesign seating areas at departure gates.

But there are other ways of reducing bottlenecks at airports, for example by using visual displays to nudge passengers so that they don’t rush the gates. Hansen’s team wants to keep them seated until their row is due to board the plane. “The nudge-intervention here consists of two elements, both based on the principle of providing visual information,” says Hansen. The departure gate, for example, could have two screens, one to show the names of people who are due to board the plane, while the other has calls to action, like "please keep seated" and "find your passport and boarding pass". The visual cues basically work like traffic lights. 

It’s not just in airports that such nudges are useful. In Singapore, the Land Transport Authority (LTA) and the Singapore Kindness Movement did a six-month-long study last year to persuade passengers not to occupy seats reserved for disabled or older travellers.

Instead of simply making the “reserved seat” signs more visible, the team turned to positive phrases such as “Be sweet” and “Show you care” to point passengers in the right direction. They also coloured these seats in bright colours and “happy” patterns, making it obvious that these seats were for people most in need of sitting down.

A similar nudging strategy has been in use on Virgin Trains in the UK. To make sure passengers do not throw inappropriate objects down the train toilets, the usual stern warning signs were tweaked. They now read: "Please don't flush nappies, sanitary towels, paper towels, gum, old phones, unpaid bills, junk mail, your ex's sweater, hopes, dreams or goldfish down this toilet."

Shock-absorbing seats

Nudging can even help pedestrians to skip the escalator, and take the stairs. In a famous viral advertising video, turning a staircase in a Stockholm metro into a piano – combining piano key colours with sound effects – took thousands of commuters off the escalators and onto the stairs. In Singapore, brightly coloured stairs and fitness slogans have had a similar effect.

Some problems, of course, can’t be solved by nudging. A cramped economy class has only that much space for subtle methods, and some tougher solutions are necessary – as tough, even, as titanium. French company Expliseat has designed a so-called Titanium Seat – made of composites, carbon fibre and titanium alloy to work around the old "knees against the back of my chair" problem. It does it by not reclining back into the seats of the person behind – the seat is in a fixed-recline position, giving the occupant a more comfortable seating position. The seat is lighter than standard seat models, and is also much more shock-absorbent.

So far, these seats have only been installed on one Airbus A321 of the Air Mediterranee airline, on a flight from Paris to Marrakech in Morocco. Elsewhere in the world, some passengers may still resort to their own gadgets such as the Knee Defender. At least, until they’re gently nudged not to…

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