You might have noticed that the smell of grass and rubber cleats can bring back the memory of childhood soccer games in starker detail than watching an old movie of a game your parents filmed. Smells have a stronger link to memory and emotion than any of the other senses, and neuroscience may know the reason why. When you see, hear, touch, or taste something, that sensory information first heads to the thalamus, which acts as your brain's relay station. The thalamus then sends that information to the relevant brain areas including the hippocampus, a seahorse-shaped structure responsible for memory, and the amygdala, an almond-shaped area next to the hippocampus that does the emotional processing. But with smells, it's different. Scents bypass the thalamus and go straight to the brain's smell center, known as the olfactory bulb. The olfactory bulb is directly connected to the amygdala and hippocampus, which might explain why the smell of something can so immediately trigger a detailed memory or even intense emotion.
But why, if we're such visual creatures, does smell get this elevated status in our brains? Some think it goes back to the way we evolved: smell is one of the most rudimentary senses, with roots in the way single-celled organisms interact with the chemicals around them, so it has the longest evolutionary history. This also might explain why we have at least 1,000 different types of smell receptors but only four types of light sensors and around four types of receptors for touch. We've collected some awesome videos on this topic. Watch them now to learn more.