When one head is better than two

File Photo / Thinkstock

According to the old saying, two heads are better than one but in many cases, you are better off thinking for yourself, say researchers.

Scientists found that group decision- making is more likely to yield the correct answer to a question only when it also seems to be the most logical answer.

When it is something unexpected or requires creative thinking, individuals tended to fare better on their own and speaking to others made them lose confidence.

Professor Asher Koriat, of Haifa University in Israel, asked 38 people to answer a series of questions individually and in pairs. He asked them to say how confident they were in their answers in each case.

For general knowledge questions such as which of two European countries has the larger population, it was clear that two heads were better than one. And three heads were even better than two.

He then turned to trick questions a series of pictures containing tricks of perspective where the participants had to decide which line was longer or which object was bigger in a drawing intended to mislead. He also asked questions that many people would get wrong, such as whether Sydney or Canberra is the capital of Australia. The answer is Canberra, but most people would say Sydney.

In that test, when the study participants were asked to discuss the problem in pairs and come up with one answer, it was generally wrong. In fact, the pairs did on average worse than the worst individual.

Professor Koriat said previous studies which had fuelled theories about the 'wisdom of crowds' were right, but only if the answer to the question tended to be most popular or most logical one. His results suggested people who were most confident in the answer they came up with on their own tended to be right. So pairs could work better together if people were honest about how confident they were.

When it comes to questions that would fox most people, Professor Koriat said: 'In such cases it is the low-confidence individuals who are more likely to be correct, and reliance on the more confident members should lead the group astray.'

Professor Koriat's study is published in the journal Science.