By Miranda Levy

Copyright theage

Smith, 66, is not alone in this assertion. An increasing body of evidence is showing that our mood, cognition and general wellbeing are intrinsically linked with how well we are able to sense our environment through our olfactory receptors.

“Everyone has historically talked about hearing, touch and vision, but in neuroscience, less attention has been spent on smell and taste,” he says. But the indications are that this is starting to change.

While we may not consciously dwell on it, our sense of smell is our most evocative. Even decades later, a certain scent can bring memories back to life: the brand of washing powder your grandmother used, or a perfume you wore as a teenager. For Smith, it’s Ambre Solaire, bringing back family holidays. For this reporter, Germolene, as applied to childhood cuts and bruises.

Scientists describe these moments “like a key being inserted into a lock”. Our noses contain hundreds of odour receptors, each primed to interact with specific molecules. When those molecules enter your nose and bind to their matching receptors, sensory neurons fire electrical signals which whizz to different parts of your brain.