Short answer
Scent can influence buying behaviour, but not in a simple way. A suitable ambient scent can contribute to mood, shopping experience, memory and approach behaviour. That does not mean that every pleasant scent automatically leads to more sales.
Scent first changes the context
Consumers never make decisions completely independently of their environment. Light, music, crowds, temperature, routing and scent together form the context in which products are viewed.
A pleasant scent can cause an environment to be evaluated more positively. When the scent also logically matches the shop, the product or the brand, that effect can be stronger. Research on olfactory congruence shows, for example, that a suitable scent can influence attitude, enjoyment, store atmosphere and, in certain situations, spending.
No invisible sales button
It is tempting to present scent marketing as a technique that makes customers buy more without them noticing. That is too simplistic.
A classic field study in bookshops, for example, did not find that thematically matching scents increased sales of matching magazines. Other studies, on the other hand, did find positive effects of scent on shopper responses. The scientific literature therefore shows that scent works under certain circumstances, not that scent has the same effect everywhere.
So where does the value lie?
The main value often lies in the overall experience. A shop that feels calm, well cared for, coherent and recognisable reduces friction. Scent can be an extra layer in that.
When the scent suits the desired brand personality, it can help make the environment feel more consistent. A fresh, mineral concept communicates something different from a warm woody accord. Those associations can then play a part in how customers judge a brand, product or space.
Scent and memory
Scent is also a powerful context cue for memory. A scent that is consistently combined with a brand can later evoke associations with that environment again. That makes scent interesting for brands that want not only to influence an immediate purchase, but also to build recognition.
What does this mean for retailers?
Anyone who wants to test scent marketing would do well not to look only at turnover. Also measure length of stay, conversion, average spend, customer satisfaction, spontaneous brand recognition and qualitative feedback.
Also compare periods with and without scent and don't change music, routing, prices and promotions at the same time. Otherwise you won't know which element made the difference.
The right conclusion
Scent can influence consumer behaviour, but it is not a stand-alone trick. The best results can be expected when scent is pleasant, subtle and congruent with the brand and when the rest of the environment supports the same direction.