Humans are one of the only species with an additional layer of consciousness and rationality above mere instincts that drive behavior. Precisely how much of this layer is real and how much is illusory is a subject of great debate among philosophers and neuroscientists. Nonetheless, we tend to think that our day-to-day relationships are largely a matter of conscious and rational decisions. We communicate to others only what we wish. There is the occasional Freudian slip, but we are otherwise largely in control.

But in recent years, a number of studies in psychology have shown that human communication is largely composed of what biologists call signaling. That is, if an organism wishes to communicate a trait not visible to others — immune system strength, for example — it can emit a signal, a different trait which is highly correlated with the real trait it wishes to express. The archetypal example is the peacock’s tail. Its intricate colors and size suggest a healthy animal. In humans, signals can take many forms, but are most often related to body or facial proportions.

Current research is highlighting that such signals are a reliable predictor of who we really are, oftentimes outperforming our conscious introspection. In his book “The Tell,” psychologist Matthew Hertenstein cites one particularly interesting experiment in which children are told a story about a sea voyage and then shown pictures of two politicians who ran in a parliamentary election. The children are then asked who they would prefer to captain their own ship. Their choice of captain correctly predicted 71 percent of parliamentary election outcomes.

The idea that human communication is as much about involuntary signals as it is about language has more or less always been suspected by behavioral scientists. But it is only in recent years, that controlled experiments and insights from biology have provided serious evidence for such a claim.

But these insights on human signaling come with a crucial caveat — with nearly every signal there is some background noise. This noise may represent disruption in growth or development, genetic defects, or maybe even personal choice. At least in the case of human signaling, this background noise can be considerable — sometimes as much as 60 percent of the variance.

There are two things to be aware of when reading these studies. First, they rely on a statistical trend, which doesn’t apply to all individuals. For instance, some people will not wrinkle their eyes when smiling and still be authentically happy. Second, these findings show that sometimes we are affected more by signalling than by personality. We therefore have the potential to incorrectly judge others — an obvious example here is the fact that a person’s displayed confidence has nothing to do, in principle, with the underlying honesty of the individual.

While these studies may provide insights into the nature of the human mind and communication, they are not to be taken so seriously that one lives their social life by them. In this case, as always, the goal of scientific inquiry is an explanation for the underlying laws of nature — not a guidebook for life.

Marcelo Cicconet is a staff columnist. Nickhil Sethi is a contributing columnist. Email them at [email protected].