So we've seen that fight-or-flight responses and our own scents play a part in our bid to survive. But did you know that a baby's cry is also a survival mechanism? Many animals are born with the ability to survive on their own. Humans are the only animals that are born almost completely defenseless and depend on parents to provide everything from safety and shelter to mother's milk. The one thing a human baby has hard-wired into its system is the ability to cry. No one teaches babies to cry. It's an automatic response to let the parents know that they need something. This fact is further illustrated by the notion that babies can change the pitch and volume level of their cry to indicate how serious their situation is.
Another hard-wired example is the fact that humans are instinctively turned off by bitter foods. Sugary foods typically supply energy, while many toxic plants have a bitter taste. If you feed a baby some sweet banana mash, she'll probably eat it up. If you give her some mushy rhubarb, she'll most likely spit it out. While rhubarb isn't dangerous, it's bitter, and our natural hard-wired instinct tells us to spit it out because it could be toxic.
You also can see how food plays a part in all of this by looking at humans' diet. Our most robust ancestors lived on fatty diets that were high in calories. After all, it takes a lot of caloric energy to hunt and forage all day. Those who ate this rich diet lived longer than those who didn't and reproduced more as a result. Humans still instinctively crave that high-calorie diet, even though our days of hunting are pretty much over. You may not want to admit it, but you crave that meat and potato more than the beet salad -- unless of course, you're a vegetarian. However, a lot of vegetarian foods are shaped and flavored like meat. Is this further evidence that we all crave the same meat-rich diet as our distant cave-dwelling cousins? Perhaps.
A study published in the Proceedings of the National Academy of Sciences indicates that humans are also hard-wired to notice trouble. The study's subjects watched images of various outdoor scenes, two at a time. The second image was slightly different from the first. The changes involved a variety of things, from living animals and humans to inanimate objects like cars and wheelbarrows. The results showed that we identify changes much faster and more accurately if they're living things. Nearly 90 percent of the living changes were spotted, compared with 66 percent for inanimate objects. In other words, we're naturally wired to look out for living things. Just as our ancestors scanned the landscape for the charging wildebeest, we're still on alert for anything that could potentially be a threat.
If you want to learn more about the human psyche and how we evolved over the years, visit the links on the next page.