The human body is a complex system that has evolved over thousands of years and has developed ways to interact with nature. Although modern humans have come a long way from their original way of life, our bodies have preserved almost all the tools they used at that time. For example, our eyes can adjust our vision in a way that allows us to easily distinguish delicious fruit in a heap of leaves. This means that we can easily spot objects in our environment, but we may sometimes miss things that are right in front of us, like the car keys on the table. Our ancestors often lived near rivers, so our brains have adapted to ignore constant noise, such as the sound of a waterfall or the flow of a river. We can also ignore other types of noise, like traffic or the hum of a crowd.
Our sense of smell and taste have always worked in tandem—the smell answered, “What is it?” and the taste—”Do I want to eat it?”. These two senses were the only way to test food for suitability for consumption—which is why we are now able to distinguish a huge variety of tastes and smells, even though there are only four flavors. Or at least that’s what the researchers used to think about 120 years ago. Only recently have they added a fifth to the main four tastes.
