In a 1995 experiment, researchers attempted to show that monkeys with lesions in or even wholly removed striate cortexes also experienced blindsight. To study this, they had the monkeys complete tasks similar to those commonly used on human subjects. The monkeys were placed in front of a monitor and taught to indicate whether a stationary object or nothing was present in their visual field when a tone was played. Then the monkeys performed the same task except the stationary objects were presented outside of their visual field. The monkeys performed very similar to human participants and were unable to perceive the presence of stationary objects outside of their visual field.