Here are 5 psychological reasons Alexandria Ocasio-Cortez's bartender past gets brought up again and again

• Some conservative pundits use the fact Congresswoman Alexandria Ocasio-Cortez worked as a bartender to discredit her.
• Psychologically, the rich are more likely to see themselves as "better" than working-class people to justify their status.
• Most Americans also perceive white-collar work as more prestigious than blue-collar work.
• Visit Business Insider's homepage for more stories.

Some pundits have used "bartender" as a dirty word to discredit Alexandria Ocasio-Cortez's authority as a congresswoman. Piers Morgan, for instance, recently mocked Ocasio-Cortez's past work as a bartender after she questioned Ivanka Trump's attendance at the G20 Summit.

Experts say critics use Ocasio-Cortez's past work as a bartender, along with the fact she's young, to undermine her policy experience and question her credibility.

Yet there are also hidden, psychological or sociological reasons behind using "bartender" as an insult.

Let's unpack them.

1: It has everything to do with status.

Studies have shown wealthy people, moreso than average Americans, think they are more competent at performing tasks than the working-class. Research also suggests that people tend to perceive white-collar jobs as more legitimate than blue-collar ones, regardless of how an individual got that job or how hard they work.

Michael Varnum, an assistant professor of psychology at Arizona State University, has done formative studies on how people of different socioeconomic status (SES) backgrounds belong to distinct cultures - and be quick to judge people who belong to other perceived groups.

The story the develops is this: Stereotypes about blue-collar work, combined with how the rich see themselves as superior, leads to assumptions about how working-class people make for worse leaders.

"It makes some sense that folks might view a low SES background as implying that a person might not be desirable as a leader," he says, "given the pervasive stereotypes about class and the tendency of high SES folks to believe they are superior to others."

2: Americans (especially) believe in meritocracy.

From the start of modern agricultural society, humans stratified themselves to different hierarchies - rich and poor being one of them.

In the US, the ethos of the "American Dream" suggests have-nots can move up the wealth hierarchy solely through hard work, says cultural scientist and author Alana Conner. While European societies tend to attribute success to luck, Americans tend to blame lower-class people for their lack of work ethic as a barrier to getting ahead.

In reality, the US has one of the lowest rates of social mobility among developed countries. Most Americans who are currently rich had rich parents - with the financial resources and connections that comes along with high-status.

"The US is a culture that believes that the situation of your life reveals something about the kind of person you are," Conner said.

3: Gender is also a factor.

Some attacks against Ocasio-Cortez's previous job results from the fact she held a job perceived as men's work, according to Karyn Lacy, an assistant professor of sociology at the University of Michigan. The US barred women from bartending in the mid-1900s, for many then (and some still) saw the job as "inappropriate" due to its association with alcohol.

While women make up the majority of bartenders as of 2004, harassment and gender discrimination are commonplace.

4: Wealthier people think they're generally better at everything.

The rich see themselves as better than average in intelligence, honesty, attractiveness, and memory than those of lower socioeconomic status, according to research by Varnum.

The rich self-report themselves as "better" even when, objectively, they are not. Varnum found rich people reported themselves as better than average drivers, other research indicates people who own expensive cars tend to be worse on the road.

5: Jobs are considered a fair way categorize the world.

Jobs can also be categorized in hierarchies, with prestigious white-collar jobs at the top and blue-collar jobs at the bottom, according to Nour Kteily, an associate professor of management & operations at Northwestern Kellogg.

Unlike racial or gender hierarchies, which many people perceive as unfair, Americans generally accept that there are some jobs that are inherently "better" than others.

For instance, doctors are more inclined to view their profession as having prestige, and should have higher pay than a firefighter. Interestingly, a firefighter may also say doctors deserve better pay for having a more prestigious job, Kteily says.

And yet: Using "bartender" as an insult could backfire for conservatives.

Critics use the fact that a bartender is lower on the occupational hierarchy to undermine Ocasio-Cortez's credibility. But because 30% of Americans identify as working-class, and states with large shares of blue-collar jobs voted Republican in 2016, demeaning a minimum-wage, working-class job may insult the important voting bloc.

Republican bartenders may view the congresswoman in their "ingroup," or a group identity that people tend to make decisions alongside.

"The way that we evaluate the world depends on which social categories are salient, and the GOP is banking on the partisan category being salient," Kteily said. "I think Democrats may get a lot of purchase from trying to prime among working class members of the GOP the working-class category rather than the GOP category."

In other words, Kteily argues that if conservative attacks against bartenders and other working-class jobs persist, Republican blue-collar workers might end up voting blue if they closely identify with their occupations.

Per Ocasio-Cortez: "What is so appalling ... about having an honest job?"