To bring to light instances of unconscious and subtle biases, researchers observed a quarter of a million Americans and they found that they were less likely to respond to an email survey if they believed the sender was black rather than white.

This shocking discovery was true across all racial groups apart from black Americans, who weren’t prejudiced and were just as likely to respond to a black person as a white person.

Ray Block, a Brown-McCourtney Career Development Professor, said the findings help illustrate the day-to-day discriminations that people of colour often face.

Professor Block, who also teaches political science and African American studies at Penn State, said: “More blatant types of racism like physical violence and verbal abuse are certainly a problem, but we wanted to look at the subtler, less extreme stuff that has a tendency to build up over time.

“It’s the microaggressions and indignities that add up over the course of a person’s life.

“Microaggressions are little things that need to be considered because we think the little things matter.”

According to Professor Block and his team, while there has been a lot of prior research on more overt forms of racism like racial violence and stereotypes against minority groups, fewer studies have been done on smaller and more common types of racial discrimination.

For their study, which uncovered the racial biases in communication, the researchers contacted 250,000 email addresses, that had been pulled from both a nationwide voter registration list and a commercial email list.

The sample of participants included a percentage of Asian American/Pacific Islander, Black, Hispanic/Latino, and white respondents, all reflective of the current population breakdowns.

The email requested the recipients to volunteer their time to “take a survey about contemporary political issues”, by clicking a link in the email.

The emails were designed to appear as though they were being sent by either an outwardly black name or an apparently white name.

All the recipients received two emails in the space of a few weeks apart – one from an assumed black sender and one from an assumed white sender.

If the first email was sent from an assumed black sender, the second came from an assumed white sender.

The researchers did this to make sure each person received both conditions of the experiment.

Professor Block explained that his team tracked whether people were more likely to open the email and click on the survey link from black or white senders.

He added: “A lot of prior studies on racial beliefs have been attitudinal, where researchers asked people about their feelings about minority groups.

“But in those types of studies, people will often hide or not be truly honest about their beliefs. Our measure of discrimination is behavioural.

“We didn’t care about what people said, we cared about what people did.”

Overall, 1.6 percent of the participants responded to the sender assumed to be white and 1.4 percent responded to the sender assumed to be black.

This translated to the white sender receiving 4,007 responses while the assumed-to-be black sender received 3,620 messages back.

This meant that the change of the white sender receiving a response skyrocketed to 15.5 percent higher than a black sender.

In light of the study’s results which clearly pointed out the racial disparity in the replies sent to each assumed sender, the researchers continued to analyse what kind of lasting footprint this will have on society.

Professor Block said: “Our definition of discrimination had nothing to do with ill intent and everything to do with disproportionate treatment in some kind of way.

“And we did find that. Additionally, we still found that result when breaking it down by geographic region.

“People might assume discrimination may be worse in certain parts of the country, but we didn’t find that.”

Because the survey was the real deal, the team is planning to conduct further studies on the data they collected from the participants’ thoughts on current affairs.

Professor Block said: “Since we were able to capture people’s tendency to discriminate in this study, we could use this information as we analyse the responses to the actual questionnaire.

“What if discrimination correlated with partisanship, what if it correlated with opinions about policy?

“Future research can explore these and related questions.”

The study was published in the Proceedings of the National Academy of Sciences journal.