Who is more likely to “go negative” on an opponent’s character in a presidential campaign? A new study suggests it is Republicans.

The study, by University of Missouri professor William L. Benoit, found that during much of the last half-century, Republican presidential candidates have aimed a larger proportion of their attacks at their opponents’ character — their honesty, integrity, leadership skills — than their Democratic rivals.

Benoit found that in television campaign ads aired between 1952 and 2000, for example, GOP candidates focused 44 percent of their attacks on such personal issues. Democrats did so about 33 percent of the time.

The remainder — a majority for both parties — of attacks were based on policy differences.

The last election showed a striking disparity. In 2000, the Bush campaign focused 43 percent of its attacks on Al Gore — in television ads, debates and speeches — on issues of character, while the former vice president devoted 16 percent of his attacks to such issues.

The study is based on a sampling of campaign television ads, direct mail, convention speeches and general election debates. Benoit said he did not examine the entire record — or even a necessarily representative sample — because many of those ads and mailings have not survived over the years.

But Benoit said it was the largest-ever study of its kind and one that may have some bearing on this year’s election.