PHILADELPHIA (CBS) – Harry Potter and Donald Trump aren’t two names you usually hear in a sentence together.

And according to a new study, fans of Harry Potter are typically not fans of the Republican presidential nominee.

The study found that reading Harry Potter books led Americans to have a lower opinion of Trump. In fact, the more they read, the greater the effect.

The study is called ‘Harry Potter and the Deathly Donald?’ 

The author of the study, Professor Diana Mutz, tested the Harry Potter effect by focusing on three themes from the books: The value of tolerance and respect for difference; opposition to violence and punitiveness; and opposition to authoritarianism.

Mutz says in each case, Trump’s messages are opposed to the lessons expressed in Harry Potter and closer to that of his nemesis, Lord Voldemort.

The author polled a nationally representative sample of 1,142 Americans in 2014, and again in 2016, asking about their Harry Potter consumption, their attitudes on issues such as waterboarding, the death penalty, the treatment of Muslims and gays, and — in 2016 only — their feelings about Donald Trump on a scale of 0-100.

Each Harry Potter book read lowered respondents’ evaluations of Trump by roughly 2-3 points, according to the study.

Mutz says,”This may seem small, but for someone who has read all seven books, the total impact could lower their estimation of Trump by 18 points out of 100.”

A person’s party affiliation did not affect the likelihood of them reading the Harry Potter books, according to the study.

Viewership of Harry Potter movies did not predict Trump opposition, Mutz says.