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Lego figures 'getting angrier'

Researchers have discovered that the faces on Lego Minifigures are becoming increasingly angry and less happy.

Christoph Bartneck, of the at the University of Canterbury in New Zealand, said that initially he "was amazed by their beauty and complexity", and then started to notice how "the toys have changed over time".

He said that documenting the faces of the figures was "quite a job".

Mr Bartneck went on to warn that it is "hard to derive a causal relationship" between angry toys and children's behaviours.

First broadcast on BBC Radio 4's Today programme on Wednesday 12 June 2013.