We can’t always believe our eyes

A blue plaque to commemorate the life and work of a great interdisciplinary thinker, whose interest was in visual illusion and what these revealed about human perception, will be unveiled tomorrow [Wednesday 10 May]. Bristol Vision Institute (BVI) at the University of Bristol will unveil the plaque to honour Professor Richard Gregory, a leading Bristol academic and psychologist.

The plaque will be unveiled by the Lord Mayor of Bristol, Councillor Jeff Lovell, together with family, friends and colleagues of Professor Richard Gregory at the Workhouse Kitchen, at the bottom of St Michael's Hill, a central point for vision scientists. This cafe was where Richard rediscovered the illusion contained in the tiles. Now known as the café wall illusion, it is a geometrical-visual illusion in which the parallel straight lines between the black and white tiles appear to be sloped.

Professor David Bull, Director of BVI and Professor of Signal Processing in the Department of Electrical and Electronic Engineering at the University of Bristol, said: "Richard was an experimental psychologist whose work has been crucial to our understanding of sensory, and in particular visual, perception and illusion.

"The plaque will commemorate Richard’s significant achievements including the rediscovery of the café wall illusion, and celebrate his connection to Bristol. We hope the unveiling will ignite thought and intrigue of this and other illusions and historical sites in and around Bristol."

The plaque unveiling will also kick start the Workhouse Kitchen-led fundraising campaign to restore and preserve the original café wall illusion that is at risk of being lost forever as the tiles are in desperate need of repair after being damaged by a bus. 

The fundraising campaign is asking for support from the general public to help repair and replace the Victorian-era tiles and sections of the wall. Specialist tiles are needed to match the exact colouring and ensure the illusion is retained.

Dr Priscilla Heard, experimental cognitive psychologist at the University of the West of England (UWE Bristol) added: "I hope the fundraising campaign to save the café wall illusion will restore this unique Bristol landmark, so that it will live and be appreciated by all that pass by."

Bristol has a rich history and reputation in vision research reaching across the sciences, engineering and the creative arts. BVI was established in 2007 to focus its strengths in this area and one of its main inspirations in doing so was Richard Gregory himself.

Visual illusions have become much more prominent in recent years, such as 'the dress' that went viral in 2015 , with millions of people claiming they could only see white and gold lace while the rest of the world was convinced it was black and blue.  This demonstrated how the brain can trick us and that vision and perception are unique and individual.