The psychology of Tetris revealed on game's 30th birthday (w/ Video)

Over the last 30 years, people across the world have spent millions of hours fitting falling shapes into rows playing one of the biggest-selling computer games of all time. On World Tetris Day (6 June 2014), the University of Sheffield's Dr Tom Stafford discusses why such a simple game is so compelling and reveals the psychology behind its enduring appeal.

In a new video, he tells how the game, which is celebrating its 30th birthday today (6 June 2014), takes advantage of the mind's basic pleasure in tidying up by feeding it with a "world of perpetual uncompleted tasks".

Dr Stafford, from the University of Sheffield's Department of Psychology, says the chain of partial-solutions and new unsolved tasks can have the same kind of satisfaction as scratching an itch.

He also explains how Tetris is so moreish that one writer once described it as a 'pharmatronic' – an electronic with all the mind-altering properties of a drug – with the Tetris Effect leaving players seeing falling shapes in their mind's eye even after they've finished playing.

Dr Stafford said: "Tetris is the granddaddy of puzzle games like Candy Crush saga – the things that keep us puzzling away for hours, days and weeks.

"Tetris is pure game: there is no benefit to it, nothing to learn, no social or physical consequence. It is almost completely pointless, but keeps us coming back for more."