London: A new book has come out with methods to help us understand why things cause irritation.

The book answers why most of us are annoyed by the very sound of fingernails on a blackboard or people speaking loudly on mobile phones in public or sitting next to a crying baby on a plane?

In the book 'Annoying: The Science of What Bugs Us', New York science journalists Flora Lichtman and Joe Palca are offering a formula for things that are likely to drive us nuts. 

They argue that unpleasantness, combined with unknown duration of the unpleasantness, added to the unpredictability of it, is what makes something annoying.

As an example, the sound of nails scraping down a blackboard is irritating because the sound mimics a scream which we find unpleasant. we do not know how long it will last and, when plotted on a graph, the sound waves vary unpredictably between very loud and very quiet which our ears find uncomfortable.

However, Palca and Lichtman suggest that people talking on mobile phones in public is as close to a modern universal annoyance as it comes because it fits all the criteria of their formula.

 "For one, it's unpleasant and distracting. Second, we don't know, and can't control, when it will end. Third, we can't not listen!" a mail quoted Palca as saying.

 "Our brains are hardwired to pay close attention to people talking and follow the conversations. The loud chatter pulls our brains away to listen to half of something we're never going to understand" Palca added.

 The duo explained why some people are more prone to irritability than others; it''s because those people like to manage their lives more and it is the ‘uncertainty’ factor that drive them their extra irritation.