Black and white can lead you to make extreme judgements

Participants in the study were offered moral dilemmas printed against either a black and white or neutral background.

Those presented in monochrome put forward more polarised views, according to the research by Dr Theodora Zarkadi, of Anglia Ruskin University, and Dr Simone Schnall, of the University of Cambridge, the 'Daily Mail' reported.

"The two experiments showed that priming participants with a black and white background resulted in them making judgements in a 'black and white' and therefore extreme manner, by giving responses closer to the scale's end points," Zarkadi said.

"The results indicate that the black and white metaphor was not driven solely by contrast because there was no comparable effect for the blue and yellow pattern in the first experiment," she said.

"Instead, there appears to be a specific connotation of black and white that relates to judgement extremity," Zarkadi added.

She added that the fact that colour can affect people's perceptions of right or wrong could have important practical implications, for example in contexts which involve judgements of others' guilt or innocence.

"Subtle perceptual stimuli in a courtroom, even in fairly innocuous objects such as the colour of floor tiles, might subconsciously influence people involved in legal proceedings, leading to biased judgements and decisions when objectivity is of utmost importance," she said.

In one experiment participants were asked to rate a moral dilemma involving a man called Heinz, whose wife is dying of cancer.

Since the pharmacist who sells the life-saving cancer drug charges more than Heinz can afford, he decides to steal the drug.

For participants in the experimental condition, the Heinz dilemma was presented on a black and white chequered background, whereas for participants in the control condition it was presented on a uniform grey background.

The study found that participants in the black and white set gave more extreme judgements that were significantly further from the scale's midpoint, compared with participants in the grey or the blue and yellow sets.

The research was published in the Journal of Experimental Social Psychology.