If Marine Le Pen, the leader of France’s far-right National Front, found herself hoping that Thursday’s terrorist attack in Paris might bolster her prospects in Sunday’s vote for president, then a substantial body of research suggests that those hopes could come true.

Terrorist attacks can shift support to right-wing parties by one or two percentage points, studies have found.

This could make the difference in the first round of France’s presidential election, which polls suggest is nearly a tie among four candidates. The candidates who place first and second will face off in a second round of voting in May.

But some studies find that terrorism can create increased polarization, which could harm Ms. Le Pen’s ability to pick off left-wing voters in the second round.