Absolute Relative

How can we translate the complexity of human perception and its relativity into a thought provoking and immersive experience?


Our perception is never absolute, but relative. Absolute Relative is an interactive installation making use of the thermal grill illusion, discovered by Thorsten Thundberg, teaching visitors the relativity of our perception and how the brain works; translating  complex ideas into  easy to grasp, fun and interactive ways, accessible to a broad spectrum of Sonar+D festival visitors. The installation was created by Maria Euler, Luka Kille-Speckter, Ava Watson, and Ker Siang Yeo, Masters students in the Information Experience Design programme at the Royal College of Art, with sponsoring from the vodka company Absolut.


Absolute Relative deceives the brain by generating conflicting data. To generate the thermal grill illusion, aluminium bars are heated and cooled in an alternating pattern using a reconfigured system of peltier elements and fans such as those used for cooling large servers.  Peltier elements warm up on one side and cool down at the other when electricity flows through them. The warm side of 8 of those elements is connected to every second bar and warms it up, the cold side of another 8 elements is connected to the other half of the bars and a fan system to cool those bars down. Those slightly warm or cold bars of the sculpture are touched together.  

The contrast of the alternating temperatures when touched at the same time creates a subjective sensation, leading to a perception of the temperature being much more extreme. To understand how this sensation comes about a Flir One Lepton thermal camera module captures the sculpture and the visitor interacting. The captured thermal image is, using processing and a Raspberry Pi, transformed into a particle system of fast and slow moving particles for hot and cold areas. If movement and, therefore, interaction is detected at the sculpture the generated particle system is reprojected onto the sculpture and the viewer to enable understanding of the process and its implications.


The interactive installation Absolute Relative, replicated the thermal grill illusion using a raised metallic panel sculpture allowing visitors to gather around. Overhead, a camera outfitted with an infrared sensor captures a heat map of the visitors and the thermal grill. Visitors are encouraged to place their hand on top of the sculpture. The reaction of most people is one of sudden shock and startled, most people immediately proclaim that “its hot!”. However, this is followed by an invitation to touch each rod on the sculpture’s surface separately, proving that in fact only a mild temperature varying from our own skin’s temperature as well as slightly cooler. Now confused, most visitors bravely touch their whole hand on the sculpture’s surface again, this time paying closer attention to the sensation which they still perceive as extreme (usually hot) but challenge their brain not to be alerted. The experience successfully starts conversations around the complexity and relativity of human perception.

To read a full feature on Absolute Relative and interviews with the artists click on the link below:


CLICK HERE To see the full feature on Absolute Relative in CLOT magazine