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The power of washroom smells and cross modal experiences

Here’s a little experiment for you. Next time you have a meal try holding your nose while you eat. What you’ll find is that your ability to taste the food will be significantly hindered. Indeed, you might find it difficult to taste anything at all. This is because the way we experience the world is cross-modal: every event is experienced through a combination of senses working in harmony. The more senses in use at any one time, the more memorable the experience.

Now, let’s apply this thinking to one of the more visceral of environments we come across on a daily basis: public washrooms. Our perceptions of a washroom – both conscious and unconscious – will be affected by a range of visual and olfactory stimuli. But what are the relative importance of these stimuli in our cross-modal experience? Does smell trump sight?

To better understand this cross-modal interplay, Initial conducted an experiment to test the physiological impact of scent. In our experiment, participants were asked to enter a range of washroom conditions, from a clean cubicle to one with unflushed faeces and another with an overflowing Feminine Hygiene Unit (FHU). In one test we introduced a clean smell, and in another a bad smell. We then measured their physiological responses using Galvanic Skin Reponses (GSR), as well as emotional appraisal and eye-tracking.

dirty toilet

Across the various washroom set-ups, we found that the introduction of a bad smell significantly increased physiological reactions. For example, participants experienced a 39% increase in emotional impact when they encountered an overflowing FHU, 28% when they witnessed toilet paper on the cubicle floor and the toilet seat up, and 16% for an unflushed toilet. Importantly, the memory of bad smell scenarios seems to have lasted longer: following the bathroom experience, people rated their disgust higher in the bad smell environment (+24%) compared to the good smell environment, and cleanliness lower (-8%).


These findings suggest that a bad smell plays a significant role in activating cross-modal responses and that these responses have a greater impact on our emotions and our memory. They also appear to have an immediate unconscious effect on our actions. Eye-tracking data, for example, showed that 91% of people experiencing a malodourous washroom look around to detect the source of poor hygiene. Perhaps more tellingly, our test subjects spent on average 2.5 seconds less in the bad smell environments.

Our findings suggest that while all experiences are multi-modal, smell does indeed appear to be one of the more important inputs; triggering a wide range of physiological responses and behaviours and abiding in our memories for longer. This, of course, has huge significance for the companies that own and operate such toilets. We know from the 2017 Air Care Study that 67% of people say they’re much less likely to shop again at a retailer with a malodorous washroom. Our latest experiment suggests that a bad smell combined with poor hygiene elements would make the experience cross-modal and, therefore, even more powerful. The implications are clear: if retailers want their customer to keep coming back, they need to create a great washroom experience. This means ensuring that bathrooms both look clean and smell great.

The science of washrooms: How scent drives phsycological responses

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