Smell is often considered to be a particularly evocative sense: if you haven’t yourself been transported back in time by a nostalgic scent then you’ll almost certainly be familiar with the phenomenon via reference to the famous Proustian rush. Scent is also increasingly being used in marketing, with some evidence suggesting that smell can influence consumers’ judgements and decisions.
A new study, published in the Journal for Consumer Psychology, takes a closer look at how smell interacts with other senses to influence our perceptions. The team, led by the University of South Florida’s Dipayan Biswas, finds that looking at food before smelling it may enhance our enjoyment of what we eat.
We’re all familiar with the phrase “healthy body, healthy mind”. But this doesn’t just refer to physical fitness and muscle strength: for a healthy mind, we need healthy senses, too. Fortunately, there’s now a wealth of evidence that we can train our many senses, to improve not only how we use our bodies, but how we think and behave, as well as how we feel. Trapped as we are in our own “perceptual bubbles”, it can be hard to appreciate not only that other people sense things differently — but that so can we, if we only put in a little effort.
But if we’re going to make the most of using and improving our senses to enhance our wellbeing, we have to consider more than sight, hearing, taste, touch and smell. Aristotle’s desperately outdated five sense model may still be popular, but it vastly under-estimates our extraordinary human capacity for sensing.
Though some research has challenged the common conception that scent is the most evocative of all the senses, it can be undeniably powerful when you catch a whiff of something that jogs a memory. We also know that scent plays a part in sexual attraction: people with a keener sense of smell often find sex more pleasant and may even have more orgasms during sex, and the scent of a partner can reduce stress and increase feelings of safety.
A team of Dutch social psychologists has proposed a simple solution to the litter problem on trains – infuse carriages with the citrus scent of cleaning product. Martinijn de Lange and his colleagues made their recommendation after conducting a field experiment in which they concealed seven small containers of cleaning product (spiced up with a little Capitaine perfume oil) in the luggage racks of two carriages on a train travelling between Amersfoort-Schothorst and Enkhuizen, a journey of one hour and forty-four minutes.
The amount of rubbish not in bins on these two carriages was collected at the final stop, counted and weighed and compared with the amount of rubbish left in two, scent-free control carriages. Based on measures taken over 18 journeys, the average amount of rubbish on the unscented carriages was more than three times the weight of the rubbish collected from the scented carriages (35.6 grams vs. 11.7 grams). In terms of individual rubbish items, there were an average of 5.1 in the control carriages per journey vs. 2.7 in the scented carriages.
For comparison, rubbish was also collected from these exact same carriages over several journeys a week or so earlier, prior to the use of the scent (the train company agreed to use the same train on the same route during the period of the study rather than following their usual practice of rotating train stock across different routes). In this case, there was no difference in the amount of litter left in the different carriages.
“It seems to be possible to change the littering behaviour of people in a train environment using a simple and relatively cheap intervention,” the researchers said.
Why should the scent of cleaning product have had this effect on passengers’ littering behaviour? de Lange and his colleagues think the effect probably occurs via the non-conscious priming of cleaning related motives and behaviours. Supporting this account, a 2005 lab study (pdf) reported that exposing participants discreetly to the smell of citrus cleaning product led them to list more cleaning-related activities in their plans for the day and to spill fewer crumbs when munching on a cookie. “The positive results of our scent manipulation in a field setting provide support for the idea that the cognitive route of scents to behaviour can be used as a tool for behavioural change,” de Lange and his team said. “Merely dispersing a scent seems to trigger related goals and influence subsequent behaviour.”
Alternatively, perhaps passengers grew sick of the citrus smell and simply avoided sitting in the scented carriages! That would explain a surprising finding I didn’t mention earlier – that rubbish in the non-scented carriages (but not the scented ones) was higher during the intervention period than during the earlier comparison weeks. The researchers put that down to the intervention weeks being busier than the comparison weeks, leading to more rubbish in the non-scented carriages (but not in the scented carriages because of the behavioural effect of the scent).
de Lange, M., Debets, L., Ruitenburg, K., and Holland, R. (2012). Making less of a mess: Scent exposure as a tool for behavioral change. Social Influence, 7 (2), 90-97 DOI: 10.1080/15534510.2012.659509