New York, May 16 (IANS): Were the sentencings in the trials of Boston Marathon bomber Dzhokhar Tsarnaev and Colorado movie theatre shooter James Holmes influenced by the belief of jury members in pure evil?

A new study suggests that our belief in pure evil influences our feelings about capital punishment.

Researchers asked 200 participants -- each of whom had been given a summary of a case in which a murderer confessed to his crime -- about his or her support for different types of sentences.

These included jail time with community service, jail time with the opportunity for parole, jail time without the possibility for parole and other options.

"We found that as people's beliefs in pure evil increased, they were more likely to support sentences like life in prison without parole and even the death penalty," said lead researcher Donald Saucier from Kansas State University.

"We found that this actually happened through our participants perceiving the murderer as a demon and feeling that there was some need for retribution for the murder committed," he added.

Researchers then changed the murderer's characteristics to be consistent with stereotypes about evil.

"But, if they believed in pure evil, the characteristics didn't matter. They were more likely to support the death penalty or life in prison. The belief in pure evil overrode our stereotypically evil person," Saucier said.

This belief helps explain how opinions of others are formed during social interactions and how believing whether a person is "good" or "bad" at his or her core shapes those interactions.

Moreover, it may help explain how a court jury or judge is likely to assign punishment for a crime.

While a belief in pure evil probably would not prompt a guilty verdict, it may influence the jury's sentence, he said.

Saucier said it's likely that life experience more than religion influences belief in pure evil.

When investigating whether a religious upbringing was linked to a belief in pure evil, researchers found that people's belief in pure evil did not necessitate a belief in pure good and vice versa.

"This belief may change based on traumas, victimisation and celebrations of human success in our life," Saucier said.

The study was published in the scientific journal Personality and Individual Differences.