People sometimes get fooled by static images believing they are in motion. Scientists tried to find the reason behind this phenomenon with the help of flies.
The neuroscientists from Yale University found that flies are tricked by optical illusions as easily as humans.
They chose flies for their experiment as its easy to track the activity of neurons in their visual system.
During the research, the neuroscientists presented flies with optical illusions and observed if they perceive the motion in it the same way humans do.
To their surprise, the researchers noticed that the flies turned in the same direction as the motion that humans perceive in the pattern.
"It was exciting to find that flies perceive motion in static images the same way we do," said Damon Clark, associate professor of molecular, cellular and developmental biology and of physics and of neuroscience at Yale.
The scientists also studied specific neuron types that govern motion detection in the insects. They turned the flies’ neurons on and off and found that they were able to change the insects’ perception of illusory motion.
What turned out to be interesting was that the researchers eliminated the illusion entirely by switching off two types of motion-detecting neurons.
Besides, by turning off only one of the two types of neurons, they made the flies perceive illusory motion in the opposite direction.
Then the neuroscientists attempted to test if their theory also applies to humans. Their experiment suggested human visual systems are more complicated than that of flies. However, they found that a similar mechanism underlies this illusion of motion in humans.
The findings of the study were published in the journal Proceedings of the National Academy of Sciences.