Will Ratcliff

Sensory illusions -- like magic tricks -- work by taking advantage of the brain's assumptions, essentially forcing us to overlook sleight of hand or optical illusion. Now researchers say that these sensory biases can be "hacked by a carefully engineered illusion" -- which even works on single-celled organisms.

The University of California, San Francisco research, published in Science Express, was "a bit of an accident" according to Wendell Lim, the study's senior author. Specifically, the team exposed yeast to a small increase in salt -- described as a "mild stressor" -- and then oscillated between increased salt level and the original salt level. Typically, the sensor molecules of such a cell would detect these changes and produce an element to protect itself. But when this oscillation occurred every eight minutes, the cells began to die.


The reason for this, the researchers say, is that the cells "falsely perceived a specifically timed pattern of stress as a continuously increasing ramp of stress". They over-responded -- and thus killed themselves.

"That was just a jaw-dropping moment," said Amir Mitchell, co-author of the study. "These cells should be able to handle this level of osmotic stress, but at one particular frequency they just go haywire. We'd never seen anything like this before." "The ability to perceive and respond to the environment is a basic attribute of all living organisms, from the greatest to the smallest," said Lim. "And so is the susceptibility to misperception. It doesn't matter if the illusion is based on molecular sensors within a single cell or neurons in the brain."

It's not just a curiosity; researchers hope that this insight into pure sensory illusion could help treat diseases such as cancer. The research suggests that specific cell types are often predisposed to misperceptions, and the hope is that cancer cells could potentially be induced to kill themselves through similar means, if one can be found. "Like us, cells have biased perceptions, based on what environmental patterns they've evolved with," says Lim. "But by understanding these biases, we can modulate their behaviour."