Should you trust unanimous decisions?

Imagine a lineup by students in Pricipal’s office. They are asked to identify a student who broke the pole in the play ground. If seven of them pick out the same child there’s a good chance that’s the real culprit and if all make the same choice then one might think the case is solved. But one can be wrong.

Contents

Paradox of Unanimity

Most of us would disbelieve this since much of our society relies on majority consensus or votes whether it’s politics, business or entertainment. For us having a majority is something good infact upto a certain point it is. But sometimes the closer we start to get to total agreement , the less reliable the results becomes. This is called the paradox of UNANIMITY.

Understanding paradox of Unanimity

This basically depends on the overall level of uncertainty involved in a situation. Let’s take an instance where a basket full of oranges has one banana in it. If we ask people to identify the banana we shouldn’t be surprised by the unanimous call.But in cases where we have reason to expect some natural variance we should expect varied distribution too.

If we are tossing a coin hundred times there are fifty percent of chances of getting heads. But if the result appears to be close to hundred percent then one would suspect something is wrong.

Suspect Identification

Suspect Identification is not as random as tossing a coin but it’s not as clear cut as telling bananas from oranges either. According to a 1994 study , 48% of witnesses tend to pick up the wrong individual out of a lineup even though many are confident in their choice.We need to understand that memories based on short glimpses can not reliable and accurate.

Systemic errors

These systemic errors don’t just appear in matters of human judgement. We can cite a very interesting example to support this.From 1993 to 2008 the same female DNA was found in multiple crime scenes around Europe. The DNA was so consistent preciously because it was wrong. It was found that the cotton swabs used for collecting DNA were contaminated by a woman working in the swab factory.

In some cases these errors arise due to deliberate fraud. Political system in countries like Iran illustrates this best.