Prepared for a career in journalism by building Ford Pintos, driving school buses and being a janitor at Kmart. I've also been a business editor, entertainment editor and nature columnist. Graduated from a college that no longer exists.

There has been much concern about political bias in the media and argument about how much broadcasters and newspapers favor one party or ideology over another.

Surveys and studies suggest political bias might be significant. For example, Harvard’s Shorenstein Center analyzed news coverage of President Donald Trump and said, “Studies of earlier presidents found nothing comparable to the level of unfavorable coverage afforded Trump. … The sheer level of negative coverage gives weight to Trump’s contention, one shared by his core constituency, that the media are hell bent on destroying his presidency.”

The public has a genuine strong interest in media bias, since it depends on the media for communication that is essential to the functioning of a democratic society.

But a deeply divided partisan public tends to get stuck on arguments about the extent of media bias and seldom gets to thinking about something far more important — an understanding of media bias, its forms, consequences, causes and cure that would transcend the partisanship of any particular period.

Bias is simply a tendency to prejudge something favorably or unfavorably. Much bias isn’t bad, just people prejudging everyday things in order to make choices simpler or even possible. For example, when someone turns on the TV, they rule out many kinds of shows from the start. When people go shopping, they begin by narrowing the options to a few familiar places.

When such preferences turn into semi-permanent judgments, they become biases for or against things. Biases based on dubious criteria or that don’t change along with reality can harm what is being judged as well as whoever is making the misjudgment.

Biases against people or groups of people are always suspect and often unfair. Discrimination based on such bias is prohibited by federal law in the cases of groups defined by race, color, religion, ancestry, sex, age, disability or veteran status.

Conspicuously absent from those protected classes are biases based on wealth, social status, cultural preferences, fitness, beauty, height and a slew of other human variations — including political affiliation. Those biases are legal and tolerated in individuals and groups to varying degrees.

Negative bias gets the most attention, but positive bias is more common and ultimately more powerful. It’s not much of a simplification to say that humans conquered the world with positive bias — the increasing ability to identify with and work with others in ever greater efforts and organizations. Positive bias, too, may or may not be fair, but unfair negative bias is more apparent.

For newspapers and other media, bias can be positive or negative, routine or problematic. All media tend, for example, to be biased in favor of their paying audience and where it lives. That’s OK because a newspaper and its community are inseparable, so it’s a bias in favor of oneself, which is ubiquitous.

In fact, until the country’s political divide became so intense, the most common bias complaint about local and regional media was that they weren’t positively biased enough about their communities. Readers and viewers are also suspicious if coverage seems to favor advertisers over other businesses.

Since media decide what gets covered and how it is portrayed, people and organizations have long tried to encourage biases in their favor. In the old days, before media companies adopted and enforced basic ethical principles, this influence often took the form of buying meals and gifts for journalists.

That rarely happens anymore, but what is common is the giving of something that can be more valuable — information useful in stories. Journalists often talk about the value of cultivating sources, but the sources are also cultivating them to bias them in favor of the kind of coverage they want. How much they succeed depends not only on how rigorously principled the journalists are, but on their predisposition and whether they can be persuaded to the desired view.

In the past, this sort of influence was more bipartisan because there was more variety in the backgrounds of journalists. Now journalists are more uniform, a downside to the positive trend toward more professionalism. Prior to this century, working class people who were bright, curious and could write were valued as reporters for their close connection to the majority of everyday people. Now media companies require college degrees, even though only 30 percent of U.S. adults are college graduates.

Journalists often go directly from college into media work. This can limit meaningful experience outside of school and the media companies. Other than family, the people they have gotten to know may be dominated by fellow students and college professors, and fellow journalists. This may limit the views and values to which they’ve been exposed and make them more susceptible to some kinds of political and ideological persuasion. They may even enjoy being members of an educated elite and generally favor their class.

Critics of media bias tend to focus on this sort of elitism and the negative bias against other classes of Americans that it can encourage. That happens but less commonly.

The main driver of media bias is a positive one — a fundamental desire to do good, to make a difference in life.

But bias toward one part of the body politic does more harm than good in a democracy — undermining instead of working toward the social consensus needed to move forward.

Journalists, media companies and journalism schools need a better understanding of the organic relationship between news gatherers and communities. Society trusts they will carry out a duty that is almost sacred, and people will increasingly demand that trust is deserved.

Email Kevin Post, editorial page editor, at