Our opinions are not inconsequential. They matter. We depend on them to make to decisions about who will lead our countries, where we work, what products we buy and how we raise our kids.

Strip away our beliefs, and we cease to be the people that we are. So how do we arrive at the principles on which we base our choices? That’s a question with some surprisingly uncomfortable answers.

Just the facts

One way of arriving at an opinion is to examine the facts and draw sensible conclusions about them. Facts, however, are elusive things.

Tell a typical Russian that, at the outset of World War II, the Soviet Union was allied with Nazi Germany and he will strongly protest, even though the Molotov-Ribbentrop pact and its aftermath are well documented. Tell him that his country did, in fact, invade Poland and Finland in concert with Hitler and he will swear that it’s a lie.

During the recent revolution in Egypt, state owned media showed images of calm in Cairo while protesters mobbed the streets. During similar events in Ukraine, I came home from a crowded Independence Squareto find an empty one shown on Russian TV.

The truth is, we get almost all of our facts second hand. We tend to believe what we see widely reported in the media, numbers that show up in Excel sheets and data in PowerPoint charts. We do this out of necessity. If we limited our opinions to what we witness first hand, we couldn’t really say much about anything.

The 3 degrees rule

Of course, we get a lot of information from media, but research shows that the relationship is reflexive. We tend to choose our sources of information to suit our views. In effect, media outlets often serve to reinforce our opinions as much as they influence them.

We often overlook to what extent the people around us shape what we think. David Armano of Edelman Digital has developed a simple yet compelling graphic that shows how it works:

It shouldn’t be surprising that that our friends, neighbors and family share our views, but what is startling is to what extent they do. Chistakis and Fowler have documented the “Three Degrees of Influence Rule” at work in areas as diverse as politics, health issues such as obesity and heart disease, and even our overall happiness.

Another salient point is how much we are influenced by people we don’t even know. The fact that we are biased by the views and behaviors of our friends’ friends’ friends means that we are mostly unaware of where our ideas are coming from. It might seem far fetched, but spend some time in another culture and the reality will hit home.

Cognitive bias

Well, even if we are influenced by those around us, surely when we have facts in front of us we can judge objectively, can’t we? Apparently not. The overwhelming preponderance of empirical research into cognitive bias suggests that we are not, after all, rational beings who coolly calculate our costs and benefits. We take short cuts and make decisions emotionally.

One of the most common forms of bias is called anchoring, the tendency to process new information according to a previous context. For instance, when asked to write down the last two digits of their social security number, research subjects with higher values will bid more in a subsequent auction.

What’s interesting about cognitive bias is how strong the effect is. Here are 10 examples of how it affects our everyday decision making.

The genes in our memes

Okay, maybe it’s not so surprising that our cognitive software has a few glitches that affect knee-jerk reactions to our environment. Yet surely the things that really matter to us and that we think deeply about are a different story?

In fact, there is some evidence that suggests that even our most profound beliefs, such as religious and political opinions, have a large component that is inborn and innate. Studies of identical twins reared apart (pdf) show medium to strong correlations for religious and political opinions, but very weak links in fraternal twins that were separated.

It stands to reason that if our genetic make-up influences such core beliefs that we are also born with predispositions for approaching business decisions. Of course, that doesn’t mean that our career path was determined in the womb, but it does mean that our management choices are probably a whole lot less the product of deep reflection than we would like to believe.

Marketing’s dirty little secret

Besides our dependence of others for information, our social networks, our innate cognitive bias and genetic make-up there remains a very large pink elephant in the room: The marketing industry that routinely spends roughly $1 trillion per year to influence us.

While many in the digital world have called the wisdom of this into question, the dirty little secret is that it actually does work. Moreover, as I’ve written before, despite what you often here from pundits,surprising little in marketing has changed since the dawn of the Internet age.

Ponder that for a moment. While we trust that we are sentient creatures defined by our free will, even the dramatic increase in our access to information brought about by the Internet has had negligible impact on profit driven businesses efforts to shape our preferences. Are they fools? If so, why haven’t they been replaced by now?

The truth is that we are profoundly affected by brand marketing and not just our purchasing habits, butin how we experience and enjoy products themselves.

So what to do?

When you add it all up – our social networks, cognitive biases, genetic make-ups and all the rest – how much of our thinking is truly our own?

There is nothing more personal and intimate as our own thoughts. So it’s disconcerting, terrifying really, that we are not in full control of them. Nevertheless, they continue to determine how we will perceive and act on the things that matter in our lives.

So how do you square the circle? How can you attain surety in a nebulous world? You don’t. You just have to muddle through. As David Hume once remarked, we only believe the sun will rise tomorrow out of expedience and convenience, but we count on it just the same.

Being practical and realistic means making decisions in the face of uncertainty and accepting the fact that you will sometimes be wrong and there will most likelybe consequences.

Think about it.

Greg Satell is a blogger and a consultant at the Americal online media Digital Tonto. You can read his blog entries at http://www.digitaltonto.com