“Be careful not to let amiable discussion turn into contradiction and argument,” writes etiquette expert Emily Post. “The tactful person keeps his prejudices to himself,” and, “if he finds another’s opinion utterly opposed to his own, he switches to another subject for a pleasanter channel of conversation.”

This season places us in more situations that require polite conversation than any other time of year. But sadly, Americans writ large have lost their ability to maintain conversation with those with whom we disagree.

Due to the unfortunate state of current affairs, politics, sex and religion – topics most would like to keep off the table at holiday gatherings – can easily become the main course. Each one is a lightning rod guaranteed to divide otherwise festive guests into warring factions.

Even conversations about the weather, previously a perfect topic for small-talk, have become political minefields. Was this Thanksgiving’s heatwave a natural phenomenon, or the result of anthropogenic climate change?

What’s a civility-seeking individual to do?

Recent research reveals that the gap between the values of Democrats and Republicans is now larger than at any point since 1994. At the same time, the creation of cable news and mass proliferation of social media have helped create personalized echo chambers. In today’s media landscape, you can spend hours devouring content without encountering a single opinion that contradicts your own. High-tech algorithms constantly pump posts designed to elicit emotional responses from you, the user.

As Axios summed it up, “politics is growing more personal, polarized and pugnacious.”

But is this for the common good, much less the good of holiday celebrations across the country?

Where is the pride in isolation from people with different views?

It’s possible for good people to perceive the same issues from totally different perspectives. So how can we, as Post admonishes, not let amiable discussion turn to contradiction and argument?

In "The Righteous Mind," social psychologist Jonathan Haidt lays out his concept of moral foundations to help explain our political differences. The concept begins with the analogy that morality is like a tongue with six taste receptors.

Yes, taste. The gustatory sense.

Our physical bodies are able to sense five tastes: sweet, sour, salty, bitter and savory. Haidt contends that morality is built on six similar foundations: care, fairness/proportionality, loyalty, authority, sanctity and liberty.

However, morality is not hardwired. If so, we’d all think and perceive the same way. Rather, we begin with the same “first draft” of moral foundations. And just as we each possess different preferences at the dinner table, our senses of right and wrong are equally unique.

The care foundation developed in response to the challenge of caring for vulnerable children. It makes us sensitive to suffering, makes us loathe cruelty and seek to care for those in harm’s way.

The fairness/proportionality foundation exists to address the challenge of benefitting from cooperation without being exploited. It helps us sense when another person is likely to be a good partner. We want to see good citizens rewarded and cheaters punished in proportion to their contributions.

Haidt’s loyalty foundation developed to help form and maintain coalitions. It enables us to sense when someone is a good team player (or not). Through it, we trust and reward good team players, while wanting to hurt or ostracize those who betray our group.

The authority foundation exists to meet the challenge of developing beneficial relationships that exist within social hierarchies. We develop our sensitivity to rank or status through it, and we are able to sense when people misbehave, given their position.

Sanctity exists to help navigate the challenges of living in a world teeming with pathogens and parasites. It generates behavioral aversions that help us maintain health, which can also make us leery of symbolic threats. It is the foundation that allows us to invest objects with irrational and extreme values helpful to building group cohesion.

Lastly, the liberty foundation makes us notice and resent attempted domination. It triggers us to band together to resist oppression.

Conservatives consistently rank all moral foundations as equally important. Liberals, however, value care, fairness and liberty far more than the other foundations. It’s no surprise that conservatives and liberals see through different lenses.

Moral foundations help provide a framework for understanding others with different views. Instead of simply criticizing, they help us attempt to objectively evaluate our moral matrices. By starting with moral matrices, we can talk to each other to determine the roots of disagreement. And when we get to the root of disagreement, we often encounter otherwise unknown commonalities.

If we want to restore civility, we need to re-learn how to disagree without being disagreeable.

Maybe that relative coming over for Chanukah or Christmas Eve has no interest in seeking commonality. In that situation, moral foundations at least provide “another subject for a pleasanter channel of conversation.”

Here’s wishing you a season of pleasanter conversations.

Contributing columnist Justin Salters writes weekly on politics, culture and civic engagement; the views expressed are his own. Reach him at Facebook.com/thatjustinsalters, Twitter @justinsalters or justin@justinsalters.com.