The summer after my freshman year in high school, my family had this potent, pineapple candle that was so strong it never had to be ignited to give off its scent. Whenever we’d clean our dining room or have guests over, my mom would take the lid off the candle and let the tropical smell fill the room.
Over a year later, I once again found that pineapple candle that we never lit. I took the lid off, and suddenly was thinking about the Harry Potter books. What does pineapple have to do with Harry Potter? It took me a second to remember what my subconscious already recalled: I read through all the Harry Potter books the summer after my freshman year — the same summer of the pineapple candle.
This reaction happened because nothing reaches consciousness unless it has reached the thalamus — the region of the brain that relays motor and sensory signals — , and olfactory input (smell) passes through many other brain regions before getting to the thalamus.
“In neuroscience, we say a little bit nonchalantly that nothing reaches consciousness unless it has passed the thalamus,” Johan Lundstrom, PhD, a faculty member at the Monell Chemical Senses Center in Philadelphia said. “For olfaction, you have all this basic processing before you have conscious awareness of the odor.”
Included in those many brain regions the olfactory input passes before the thalamus are the amygdala and the hippocampus, the regions related to emotion and memory.
This means that scents can have a powerful influence on storing and recalling memories, sometimes without us even knowing it. Often, scents serve as the triggers for our nostalgia or anxiety.
We do not yet know how odor-associated memories are stored specifically, but according to researchers at Boston University’s Center for Systems Neuroscience, odor could one day be used as a tool to treat memory-related mood disorders.
“We can potentially view memory as its own kind of drug — as an antidepressant or [anxiety reducer],” Boston University neuroscientist Steve Ramirez said. “And [odor] could be an experimentally controllable factor that we could deliver to people. It may be a very powerful tool.”
Taste plays a role in memory too, because what we perceive as taste is influenced by our olfactory senses, according to Venkatesh Murthy, Harvard University chair of the Department of Molecular and Cellular Biology.
Murthy said that when we chew, molecules in the food “make their way back retro-nasally to your nasal epithelium,” so “all of what you consider flavor is smell.”
This is why people say that chewing the same flavor gum while studying for a test and while taking a test improves your memory. It sounds like a bunch of bunk, but it’s actually true because of the anatomical association between taste, scent, and memory. You could also take advantage of this fact by wearing the same perfume or essential oils, or by drinking the same aromatic tea, both when you study and take a test on the same matter.
So, as you study for your final exams, consider what you’re smelling — it could help you recall answers on test day.