Dr Braithwaite studied the Mexican cave fish, which has no eyes.

"As the fish swim though the water, they set up a flow-field around their body," said Dr Braithwaite.

"Objects and hard surfaces interfere with this flow-field and allow the fish to navigate and avoid obstacles. Information from the right lateral line is transferred to the left side of the brain where it is processed."

When the fish become familiar with the object, they can swim past it in future.