instantaneously knowing

Infants who were exposed to alcohol, cigarette smoke or garlic in the womb show a preference for the smells. To them, the smells that might upset other babies seem normal or even comforting.

While I was exposed (as much as one can be in a womb) to alcohol, cigarette smoke and presumably garlic... and have grown up to be a garlic eating, alcohol drinking smoker... there are other more pungent smells that trigger all my senses down to my olfactory bulb and my limbic system close by. The smell of musty wet rubber, neoprene and petrol. One whiff of the stuff and I'm power launched into a benzene induced state of euphoria.

smell can call up memories and powerful responses almost instantaneously.

The olfactory bulb has intimate access to the amygdala, which processes emotion, and the hippocampus, which is responsible for associative learning. Despite the tight wiring, however, smells would not trigger memories if it weren't for conditioned responses. When you first smell a new scent, you link it to an event, a person, a thing or even a moment. Your brain forges a link between the smell and a memory. When you encounter the smell again, the link is already there, ready to elicit a memory or a mood. This is part of the reason why not everyone likes the same smells.

Given that certain smells learned and loved or hated are imprinted in humans from before birth to every new event in their lifetime... there must a connection between the emotional association of smell to the science of pheromones and MHC (major histcompatability complex) - the very primitive act of smelling out your best suited partner. Surely it can't be based purely on coincidence if you both like the same smells due to your initial connection with them. While MHC focuses on pheromones and the literal ability to smell dissimilar genes to create stronger smaller creatures, based on a primal instinct - The limbic system is highly interconnected with the nucleus accumbens, the brain's pleasure center, which plays a role in sexual arousal and the "high" derived from drugs. Either way, you're physically, mentally and emotionally evoked by the 10,000 smells that each human can identify. 


My point being that if your "best suited" partner likes the smell of petrol as much as you do... then you're on par and destined to a life of lakeside summers and happily ever after. Perhaps this is a whimsical approach and it's not the smell of petrol that connects you but the appreciation of who, how and what your were brought up to love.  
So dip me a man in petrol and set the pheromones afire.