Today's election polls look dramatically different from one week ago.

On Friday, we spoke to the University of Nevada, Reno political and psychological sociology professor Dr. Markus Kemmelmeier about how Kamala Harris's introduction as Democratic party frontrunner has impacted the U.S. presidential race.

Kemmelmeier's research focuses on cultural psychology, political psychology, interaction and social cognition, and intergroup relations. He is an expert on advanced statistical methods.

Less than one week ago, President Biden trailed Donald Trump in virtually every poll. That changed last Sunday when Biden resigned and endorsed Kamala Harris.

This UNR political psychology and sociology professor will tell you that the race is tight and new dynamics continue to play out.

"This was, as far as campaigning goes, a master stroke," Dr. Markus Kemmelmeier.

The assassination attempt on former President Trump was a momentous moment for his campaign. He showed strength and bravery. But one week later, President Biden stood down and threw his weight behind VP Kamala Harris.

"This has completely reshuffled everything. Because Kamala Harris has now taken away this theme of strength, this issue is not as clear. A lot of Democrats have clearly condemned the assassination attempt, and the kind of compassion that President Trump clearly earned and deserves here, that has fizzled," said Dr. Markus Kemmelmeier.

Before Biden stood down, polls showed that many voters were dissatisfied with the choice between Biden and Trump.

"A substantial portion of the electorate said they were double haters; they didn't like their choice. And I think many of them feel energized because they see that there is a new face," explained Kemmelmeier.

Kemmelmeier says that Kamala Harris appeals to more minority voters, but there is also a large contingency of people who will show up to vote against her.

"Over the next 100 days, each party will try to find those sure-fire attack lines. There will surely be a lot of polling going on under the service after the initial phase of excitement has subsided," said Kemmelmeier.

The polls show that the race is currently a toss-up. That's why we'll see and hear from them much more in the following weeks and months.

"We are moving more to 50/50. Maybe we're at the maximum point of uncertainty. So, we don't know. So this is why you see a lot of energy on both sides." Kemmelmeier explained that the Republicans feel a sense of urgency to elevate their candidate.

"They were so confident at the end of the convention that there is a greater sense of uncertainty as to whether this is going to work out," said Kemmelmeier.

Harris raised 81 million dollars just 24 hours after President Biden's endorsement. Kemmelmeier says this shows the Democrats' pent-up frustration over Biden staying in the race.

In case you have not heard, Trump's VP pick, Ohio senator J.D. Vance, is campaigning in Reno on Tuesday.

WATCH Dr. Markus Kemmelmeier's full interview:

University of Nevada, Reno political psychology professor talks about the impact of Kamala Harris' injection into the U.S. presidential election.