Brain Awareness Week: 14–17 March

The interactive ‘Your Amazing Brain’ exhibition at Banbury Museum & Gallery begins with a collection of immersive optical illusions. The shortcuts that your brain has learned in order to make sense of the world sometimes backfire, resulting in a confusing impression of what is going on in front of your eyes.

In this fascinating series of illusions, Professor Holly Bridge explains how your brain can play tricks on you.

Faces in objects

The brain has several specialised regions that process faces. The visual system uses the relative position of facial features to identify faces, and our sensitivity to this means that faces are perceived in objects with a similar arrangement.

Disappearing dots

Our ability to see detail is maximum at the point where we are focusing, so we can always see the white dot that we are looking at. The detail in the pattern further away from where we are looking cannot be seen properly as the visual system averages over a larger area. The white of the central dots cannot be seen and instead the visual system assumes that the grey lines are continuous.

Bistable cube

The small cube is seen either as a cut-out from the large cube or protruding out of the large cube. The image is 2D but we perceive it as 3D due to the perspective information in the small cube. However, the information for these two interpretations is the same in 2D and therefore compatible with two different interpretations. The visual system can flick between both of them.

Steps

The information in 2D is compatible with two interpretations. If additional cues were added, such as binocular disparity or shading, the image would become unambiguous.

Floor hole

The pattern on the floor is the equivalent of perceiving a hole from above – the sides become less distinct and darker and the centre (bottom of the hole) is darkest, with no detail.

Curvy leaves

The visual system looks for continuity of lines when trying to identify objects, so although the leaves are in straight lines, the changing orientation of the leaves means they look like they are arranged in a curved manner. This is compatible with the contours of the leaves rather than the grid pattern of the centre of each leaf.

The 'Your Amazing Brain' exhibition is a collaboration with the University of Oxford’s Wellcome Centre for Integrative Neuroimaging. At Banbury Museum until 5 June.