Odours typically associated with cleaning products, such as citrus, have been reported to activate cleaning behaviours. The aim of the present study was to test whether odours in general or pleasant odours specifically, would also do so. Furthermore, the concentration of the odour might be expected to play an important role: it is known that clearly recognisable odours lead to fewer behavioural effects than odours that are barely noticed. Once odours are recognised they may elicit all types of conscious reasoning that can inhibit behavioural effects.
We used three odours: clearly unpleasant (Sulphur), clearly pleasant (Orange) and somewhat less familiar but also pleasant (Grass). Naïve subjects were led into special odour-controlled rooms in which each odour was dispersed, for what they believed to be a food product test. They were requested to cut a rusk into several parts, eat the parts, and then answer some questions presented on a computer screen. The behaviour of the subjects was recorded on video, and scored by several independent assessors using a structured observation method for quantitative coding and description of the cleaning behaviours observed (e.g. sweeping the table). The crumbs that remained after testing were also collected and weighted.
These results show that different odour qualities appeared to trigger different levels of behavioural effects, and in particular that cleaning behaviour is not activated exclusively by a fragrance prompting associations with cleaning products, like citrus odours. Green grass, not known for its association with cleaning, showed similar effects to Orange. We posit that odour valence plays an important role, as Grass -and Orange- are in general well liked and have positive connotations, and produced more sweeping movements than the unpleasant Sulphur.