WELLINGTON, Aug. 4 (Xinhua) -- If you're having your eyes or ears tested, be aware that you could be subconsciously skewing the results, the New Zealand co-author of an international study said Thursday.
The research, conducted with scientists in the United Kingdom and United States, showed people had a natural tendency to base their responses in tests on past decisions.
"Successfully adapting to our environment means we use information about our past successes and failures to make better decisions in the future," said Professor Steven Dakin, head of optometry and vision science at the University of Auckland.
"But sometimes the outcomes of past experiences are not helpful and taking them into account leads to worse decisions," Dakin said in a statement.
The research showed it was easier to reinforce these tendencies than to break them down.
"For example, many people switch their decision following a failure, even though such superstitious behaviour makes them perform poorly," said Dakin.
The research found this tendency could be strengthened but not weakened: existing biases could not be eradicated.
Ways to counteract the response to make better measures of performance, such as when assessing vision at an eye clinic, were presented by the study.
"People's irrational tendency to rely on their past decisions is important because vision and hearing tests assume we are rational. Without accommodating people's individual biases, the test results can look worse that they really are," Dakin said.
"We are now looking at children to see how prone they are to biases, because you could argue either way that they might be more or less superstitious than adults," he said.
"You could argue that they are likely to be less superstitious because they have less experience of the world, or they could be more superstitious because superstition has a kind of adaptive value and is a default state for the system."