The human mind is extremely malleable - illusionist Derren Brown has made an entire career out of proving as much. We have always been able to make our brain perform all sorts of contortions so that events fit our own worldview.

Last week, former BBC foreign correspondent Allan Little told the annual gathering of the Scottish Council of Independent Schools that, as social media proliferates and news providers become atomised, we have never been more vulnerable to the dangers of confirmation bias. Choose an opinion, any opinion, and the internet will gladly provide an endless supply of content that backs you up, while filtering out and distancing any dissenting voices.

An important piece of research in Glasgow has revealed a huge divide in opinion over the experiences of black and minority ethnic (BME) teachers in Scottish schools. We have no way of knowing whether it has been exacerbated in the social media age - this is the first time any Scottish local authority has analysed views of, and about, BME teachers in such detail - but the evidence is stark: BME and white teachers appear to have vastly different opinions on the difficulties involved in being a BME teacher in Scotland.

Consider this, for example: “white Scottish/white other” teachers are twice as likely as BME colleagues to report having been appointed to a promoted post. Or this: three-quarters of BME teachers feel that promoted posts are difficult to obtain for teachers from minority-ethnic backgrounds, but fewer than 10 per cent of white teachers agree. And while 66 per cent of BME teachers view potential discrimination from colleagues as a deterrent to becoming a teacher, only 11 per cent of white teachers believe this is an issue.

What’s going on here? How can two sets of people working in the same schools system have such different views when asked the same questions?

Scotland’s most prominent expert in these matters, Professor Rowena Arshad, head of the University of Edinburgh’s School of Education, is chairing a working group for the Scottish government aimed at boosting numbers of teachers from underrepresented groups. Responding to the research, she says: “It is time that employers and those that provide preparation for school leaders tackled the issue of racism within the profession, corridors, classrooms and staffrooms.”

Many will instinctively see the Glasgow findings as a sign of something subconscious and insist that this is not about overt racism (or perhaps even dismiss them because the number of BME teachers involved was small).

Arshad sees that as a complacent and craven response. Making noises about inclusion in education counts for little, she warns, if educators are “hiding behind phrases like ‘unconscious bias’” and “sliding away from confronting the issue”.

When BME teachers are half as likely to be encouraged by managers to go for promotion, and eight times more likely to believe that promoted posts are difficult to obtain for teachers from minority-ethnic backgrounds, we cannot easily unpack the reasons for the problem - but we can agree there is a problem. Equally, the suggestion that there is “a culture of ‘white privilege’ or ‘institutional racism’ within the Scottish education system” - as one teacher put it - must be confronted.

The chasm of opinion that has been uncovered by this research shows just how easy it is for one group of people to filter out the lived experience of another, for the brain to block out troubling ideas in its quest for a stress-free life. And that’s exactly why every time a teacher takes a lesson on racism, prejudice or intolerance, they should first ask themselves this: “How is our school doing?”

@Henry_Hepburn