Pleasant and unpleasant odors influence hedonic evaluations of human faces: an event-related potential study

"associations between visual and olfactory stimuli have been demonstrated in a variety of species, including honey bees (Srinivasan et al., 1998), Drosophila (Guo and Guo, 2005), primates (Rolls et al., 1996), and humans (Gottfried and Dolan, 2003; Lawless and Engen, 1977). These associations have indicated that odorants can influence preference for visual stimuli, such as faces or abstract paintings (Todrank et al., 1995; Van Reekum et al., 1999), and conversely that visual cues can affect aspects of olfactory perception, such as perceived intensity (Zellner and Kautz, 1990; Dematté et al., 2009). Combining information from both senses improves task performance (Steck et al., 2011), underscoring the episodic nature of olfactory memory. "

See also, anything reported in the context of RNA mediated events, which link metabolic networks to genetic networks and behavior in species from microbes to humans via the physiology of reproduction.