Wharton assistant professor Corinne Low didn't set out to test the effect Donald Trump's election might have on men's and women's negotiating patterns last year. A gender and family economist, she was looking more broadly into gender differences in communication styles, using experiments to look at how men and women negotiate with one another in a lab at Wharton, the University of Pennsylvania's business school. 

But after the November election, she noticed something interesting in her data. Comparing the results from lab tests she ran during early and late October with tests she ran the week after the election, she noticed a change she called "extremely stark:" On the whole, negotiating partners were more adversarial in their chat-based communication threads. In particular, men were more aggressive when they negotiated with counterparts they knew they were female, using hardball tactics more often.

"We didn’t know what to expect when we looked at the data after the election," Low said in an interview. "But the data was screaming at us that there was an effect."

In a paper called "Trumping Norms," set to be published in the May issue of "American Economics Review: Papers and Proceedings," Low and her co-author, Wharton doctoral student Jennie Huang, utilized a simple game called the "Battle of the Sexes" that gives pairs of participants $20 to split between them. Only two splits are available: One person can get $15 and the other can get $5, or vice versa. If they can't agree, both get zero.

The researchers assigned, on a random basis, who the participants faced off with and whether they knew the gender of their negotiating partner. In about half the negotiations, they used an online chat tool so their negotiation tactics could be coded as aggressive or cooperative. The October sessions had 232 subjects and the November ones had 154, with participants going through multiple rounds of negotiating, leading to 772 chat conversations that the study observed.

What they found: On the whole, the interactions were more aggressive following the election, with more people starting out by pushing for the $15 for themselves. (The researchers hired outside observers who were blind to things like gender to code the level of aggression in the conversation.) These more hardball tactics even led to lower effectiveness: More pairs "mismatched" their negotiations, leading to a statistically significant drop in the total money the negotiators took home in the post-election sample.

"Not only was the communication more aggressive, it was also less effective," she said.

Even more striking, Low said, were the results when comparing how men negotiated with known female partners after the election. Before the election, male participants were less likely to engage in tough talk or hardball tactics when they knew they were negotiating with women than men, "displaying what could be classified as 'chivalry' toward female partners," Low wrote in her paper.

But after the election, aggressive tactics toward known female counterparts surged.  The number of men who used a "hard commitment" negotiation strategy against female partners -- saying they were taking $15, take it or leave it -- went up by 140 percent from the pre-election sample. "That's a huge effect size in laboratory literature," Low said. "We've never seen anything like that."

Low acknowledges that the study was new in October, so she doesn't have data going back to compare her results to say, last year; nor does she have data that illustrate whether the change reflects a long-term trend.

"Was this just immediately after the election, people were sort of worked up and it's going to go away?" she said. "Or is it something that's shifted and is going to last the entire presidency? Those are new questions we don't have answers to."

Other studies, she notes, have shown that macro-political events do have effects on people's behavior, though Low believes the size of her findings is notable. Additionally, she notes in the paper that there was "a particular disturbance on Penn’s campus" immediately following the election. Reports showed that black freshman at the University of Pennsylvania "had been added to a racist social media group with shockingly racist words and images," she wrote in the paper. "Thus, we cannot rule out that our results are partly driven by these specific on campus events, in addition to the broader national context."

Low and her co-author also examined whether the population of lab participants might have shifted in some way. While there are some differences in demographic groups from the two time periods, they restricted the population by factors like race or political party and examined matched sample results to test for variations. Even after doing that, the results were stable, she said.

"It's not something we can 100 percent rule out, but it really suggests to us that it's people's behavior that's changing, rather than that it's the people who are changing," she said.

Asked whether she believes Trump, who has cast himself as an aggressive dealmaker and whose treatment of or remarks about women became a major campaign issue, was the cause for the change, Low was cautious. "I’m an economist, so I’m going to stick in my lane," she said. "We call the paper Trumping Norms. We find it suggestive that there was some kind of a norm shift. ... That suggests who the leader is could matter."

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